A software layer (filter driver) residing between software components or application programs running locally or on a client across a network and a persistent store of an operating system provides on-the-fly conversions of persistent information formats. The filter driver determines which format a program expects, and dynamically converts the information from its storage format to the format expected by the program. Conversion includes both data format conversion, and conversion of access semantics. Loadable conversion modules are provided for converting application specific formats due to the potential large number of such formats which can be encountered. The filter driver may change the format that information is stored in based on access history or other system requirements. The software components or application programs may be ignorant of the true storage format used by the system, and thus the filter driver can be used to give old versions of software access to information stored in newer formats.

Computer applications such as document processors, data base programs, simulators, games, editors, and compilers all need to persist information even the application is not running. Computer systems store persistent information in a variety of ways, including disk-based file systems, data bases, hierarchical storage systems, internet servers, and distributed memory. Persistent application data is stored in different formats depending on the type of application, and even depending on the version of a single application. The format of the information is what gives meaning to the binary bits which are used to represent the information. The format includes both the explicit details of how to interpret the bits, as well as the rules that are to be observed when accessing the information such as how to concurrently access the data from multiple users, how to sequence modifications to the information so that it can be recovered after a system crash, or how to maintain auxiliary data used to manage the information for purposes such as workflow management, auditing, or security. Multiple formats can be applied to the same information. The persistent storage that holds the information produced by an application is sometimes referred to as a file. The computers on which such applications run have file systems and other persistent stores which store the files out onto memory devices in yet further forms. These multiple different formats, both at the application level and at the file server level lead to difficult interoperability problems. For example, a document produced by a later version of a document processor is often not readable by a previous version of the document processor. When a user buys a new computer loaded with the latest software, produces a document, and gives a copy of the document to someone else only having a previous version of the software, the copy can be useless and indecipherable by the previous version.
Further difficulties arise when a user desires to share documents and other files over a network with a person using a different operating system or application, or even a different version of the same operating system or application. If the different systems use different formats for the information, due to changes in the applications, or internal operating system components, they may have difficulty sharing information. In particular the newer system or application may use an information format that was invented after the earlier system was developed. These difficulties also arise with different applications that use a common type of information, but expect different formats, such as image processing applications that use JPEG instead of GIF, or document processors which use HTML instead of Word7 format. Incompatibilities can also be due to the file systems or other persistent stores used by different operating systems. One type of operating system has file savers that store data files formatted as a single stream. Applications with the file server via an interface, such as OLE32, and expected the data to be returned to it in a certain format. OLE32 was specifically designed to retrieve and transfer data in the single stream format of docfiles. A newer or different type of file format may use the same set of interfaces, but store the information in a different format, perhaps relying on a file system format that supports multiple streams in a single storage container, and this results in a compatibility problem.
Prior attempts to solve the problem of using different versions of applications and different applications storing data in different formats involved the use of conversion programs which performed explicit conversions on information between formats. Thus, when opening a document, a user would be presented with a choice of converting a document to a new format prior to opening it. Also, on storing out a document, a user may select many different application level formats in which to store it. These solutions worked well for new versions of software, where the support for such conversions was built into the programs, but did not work well when an older version of software was confronted with a data format produced by a newer version. If a user of the new version failed to explicitly save the information in a format that was understood by earlier systems, the information would be unavailable to users on earlier systems. Either the earlier system must be upgraded with a new program to convert the data, or the newer program must be started again and the file converted prior to trying to use the older version to work with it. This was an unsatisfactory solution because the older application or system would not understand that the information was in a newer format, and give the user confusing error messages. Even where the format problem could be detected, there were generally no tools available on the older system to effect the conversion. The problem is also common on computers coupled by network, where a file server, remote database or other distributed persistent storage mechanism may store data in a newer file system format, or there may be multiple versions of the same software on different machines, and one user does not have access to newer versions in order to appropriately transform application information formats.
Some image processing applications keep an image file in an internal compressed format, and then use an operating system driver to transform the file to appear to be in a fixed set of well-know image formats (JPEG, GIF, etc.). It does not allow modifications to the well-known formats, and is only involved in data format conversion.
Such solutions also fail to provide more than data format conversion. The 'how to' rules associated with the format are not implemented, so users cannot share or manage the information. This type of format conversion produces a copy of the information in the old format, which can be accessed or modified independently of the original, producing inconsistencies between the separately stored versions of the information.
There is a need for an easier and more convenient way to provide interoperability between different versions of applications and operating system persistent storage systems. There is a need for such a way which does not require modifications to the applications, and that is backward compatible with existing applications. The provision of such interoperability should be transparent to a user and should also be provided in an efficient manner. Further, it should allow persistent application information to be dynamically shared and managed according to the rules of the newer format, rather than requiring users of older software to only make a copy of the information in an older format.

This patent is subject to a terminal disclaimer.

Converting information into different formats


A remote control device, which controls any of a plurality of apparatuses by transmitting a remote control signal for controlling a target apparatus in response to a user operation, detects a position of the remote control device and generates self-position information indicating the position, and specifies one of the apparatuses that is the closest in distance from the remote control device, as the target apparatus, based on the generated self-position information and a predetermined criterion. When the remote control device detects a user operation, the remote control device transmits a remote control signal corresponding to the detected user operation.

(1) Field of the Invention
The present invention relates to a remote control device that transmits remote control signals to control various apparatuses, and more specifically, it relates to a remote control device operable to control each of the apparatuses individually.
(2) Description of the Related Art
In recent years, more and more electrical apparatuses, such as audio-video, air-conditioning, and lighting apparatuses, have been provided with a function that enables the apparatuses to be controlled from a distant place using a remote control device designed for each apparatus.
A remote control device designed for one apparatus has a function to send out, according to user operations such as pressing of a button, an infrared or radiowave remote control signal having a waveform predetermined as a command for controlling the apparatus. Accordingly, if the user has the remote control device designed for the apparatus at hand, the usercan controltheapparatus instantlybysuchmeans aspressing the button on the remote control device.
The number of electrical apparatuses having the remote control function, however, has become increasingly larger these days, and it would be inconvenient if the user always has to carry many kinds of remote control devices designed for each of the electrical apparatuses in order to control the electrical apparatuses freely.
Conventionally, there has been a remote control device provided with as many buttons as necessary for controlling more than one apparatus, such as a remote control device having all the buttons to control both a TV and a VCR, for example. Such a remote control device has a lot of buttons, however, and it takes more than a moment for the user to find an appropriate button for a desired function, and therefore it is not very convenient to use such a remote control device. Similarly, a remote control device having a button for switching a target apparatus to be controlled is not very convenient, because using such a remote control device increases a number of times to press buttons for the user operations.
As one solution to such a problem, Japanese Laid-Open Patent Application No. H7-123479 discloses a remote control device operable to transmit remote control signals toward each of a plurality of apparatuses selectively, and has a light receptionunitthatreceives light froma predetermineddirection in the remote control device. The remote control device according to H7-123479 specifies an apparatus as the target apparatus to be controlled by an apparatus identification signal from one of the apparatuses received via the light reception unit, and allocates the remote control signals for controlling the target apparatus to each key on the remote control device.
According to the above-described remote control device, y adjusting the direction of the remote control device so as to receive the apparatus identification signal from a desired apparatus, the user can easily control the desired apparatus.
However, according to the remote control device of H7-123479, which specifies an apparatus as the target apparatus by receiving the apparatus identification signal from the predetermined direction, it could happen in some cases that the user controls an apparatus different from an apparatus that the user has originally intended to control, because the apparatus identification signal can reflect on house walls and such when used inside a house. Moreover, when an apparatus A, an apparatus B, and the remote control device are substantially aligned, and if the remote control device receives the apparatus identification signal from the apparatus B, the user controls the apparatus B using the remote control device even if the user has originally intended to control the apparatus A.

Matsushita Electric Industrial Co., Ltd.


Embodiments of the invention provide methods and apparatuses for concurrently eliminating or substantially reducing two or more switching losses in an inverter switching circuit. Embodiments of the invention concurrently reduce multiple types of switching losses under hard switching mode and soft switching mode for active switching devices and diodes. In one embodiment of the invention, the voltage across a switching device is substantially reduced during switch turn-off and/or turn-on time, and also maintained at a substantially reduced level throughout some or all of the tail current loss time of the switching device. Other methods and apparatuses are also described.

Power converters are employed in electronic equipment to control power delivered to a variety of loads. Power input is typically 50 or 60 Hz at standard voltages such as 110V, 220V, 440V, 2.4 kV, 3.3 kV, etc. Power converters are used to rectify the input voltage into a DC level; an inverter is then used to invert the DC voltage to an AC voltage. Industrial uses involving varying the frequency and the voltage magnitude.
Circuits used to invert the DC voltage employ switching devices which are turned on and off with a prescribed modulation pattern. This provides an output signal having a desired frequency and magnitude. For example, a typical modulation pattern that may be employed is pulse width modulation (PWM). PWM alters the width of the conduction waveform of the switching devices so that, after filtering, output voltage varies from a positive peak voltage through 0 volts to a negative peak voltage thereby producing an alternating voltage output.
Typical switching circuits employed in an inverter circuit include bi-polar transistors, insulated gate bi-polar transistors (IGBTs), gate turn-off thyristors (GTOs), silicon-controlled rectifier devices (SCR's) and integrated gate commutated thyristors (IGCTs), among others. Such switching circuits incur several types of losses including switching device losses and freewheeling diode losses (for inductive inverter circuits).
Switching Device Losses
Switching device losses include two main sources, switching loss and conduction loss. Conduction losses are the normal losses of the switching device while conducting current when running in a saturated condition. Switching losses are the losses associated with the actions of turning active switching devices on and off. Switching losses occur when there is simultaneously, high voltage across the device and current through it during transitions between on and off. Typically a power converter uses PWM with the switching device used in so-called "hard switching" mode (HSM). HSM refers to switching in which the inverter switching devices block voltage while simultaneously conducting current during transition between on and off. Power loss is incurred during this period of simultaneous voltage across the device and current through the device. This power loss is referred to as VI turn-on loss and VI turn-off loss to indicate, that for HSM, power loss is incurred each switching cycle during the turning on and turning off of the switching device. Because switching losses are incurred every time the device turns on and off, higher device frequencies result in greater switching losses.
Losses associated with turning the switching device on include the VI turn-on loss, conductivity modulation loss (for bipolar device) and capacitance discharge loss, while losses associated with turning the switching device off include the VI turn-off loss and tail current loss (in some device under certain conditions).
Diode Losses
The diode of the inductive inverter circuits incurs conduction losses (typically a function of device design and current), conduction modulation losses (incurred when the switching device is turned on), and reverse recovery losses (incurred when the switching device is turned off).
Typical losses are described more fully below in reference to FIG. 1, which illustrates a hard switching circuit in accordance with the prior art. Switching circuit 100, shown in FIG. 1 is an HSM circuit, which may be used to explain the noted sources of switching losses. Switching circuit 100 includes an IGBT switching device 105 with its collector 106 connected to the positive end 111 of a DC source voltage 110 having a voltage value of E volts. The emitter 107 of the IGBT switching device 105 is connected to an inductor 115 representing the lead inductance in series with the IGBT switching device 105. The inductor 115 is in-turn connected to inductors 120 and inductor 130.
Inductor 120 represents the lead inductance of diode 125 and is in-turn connected to the cathode 126 of diode 120. Inductor 130 is a large filter inductor and is connected in-turn to the positive end 136 of filter capacitor 135 and the positive side 141 of the load 140.
A transistor drive circuit 145 is connected to the base 108 of the IGBT switching device 105. The negative end 112 of the DC source voltage 110, anode 127 of diode 125, the negative end 137, of capacitor 135, and the negative side 142, of the load 140, are connected to ground 150.
FIGS. 2A-2F illustrate the time during which various power losses occur and the magnitude of the losses in regard to the switching circuit 100 of FIG. 1 in accordance with the prior art.
VI Turn-Off Loss
FIG. 2A illustrates VI turn-off loss. When switching off the IGBT switching device 100 (switch), the currents and current paths do not change (assuming there is a large filter inductor) until the voltage across the switch is higher than the DC source voltage 110, at which time the current will start to fall. As shown in FIG. 2A the current through the switch, represented by solid line 205, is constant from time t0 to time t1 during which the voltage across the switch, represented by dashed line 210 rises to the level of the DC source voltage 110. When the voltage across the switch reaches the level of the DC source voltage 110 (e.g., at time t1), the current will fall until it reaches zero (at time t2). Note that FIG. 2A assumes no tail current (described below) in the switch.
When the switch is turned off, the current commutates to the diode 125 as follows. The current decays at a rate determined by the size of the inductors 115 and 120 and the voltage level above the DC source voltage 110. That is, when the voltage across switch is higher than DC source voltage 110, the amount of voltage over and above the DC source voltage 110 will divide between inductors 115 and 120 with the end 117 of inductor 115 and the end 121 of inductor 120 being positive. The voltage will divide in the ratio of the size of inductors 115 and 120 such that −di/dt of inductor 115 will be equal to the +di/dt of inductor 120. This process will continue until the current reaches zero in the switch. When the current reaches zero the voltage across the switch will drop to approximately the voltage level of the DC source voltage 110.
As shown in FIG. 2A, the VI turn-off power loss is represented by hatched area 215 and occurs during the period in which the voltage across the switch begins to rise and before the current falls to zero (e.g., from time t0 to time t2). The VI turn-off loss is typically the highest of the switching losses and can be substantial especially for circuits employing HSM. For example, for a typical system in which the current is 1,000 amps (A) and the voltage is 600 volts (V), the power loss at the peak power point (e.g., time t1) is 600 kilowatts (kW) and the average power loss is approximately 300 kW over the time t0 to t2. This time may typically approach 10% of the switching period resulting in a VI turn-off loss of 30 kW.
Tail Current Loss
While the VI turn-off loss applies to circuits implementing a bi-polar device as well as to circuits implementing a field effect transistor (FET), an additional turn-off loss, particular to most circuits implementing a bi-polar switching device is the tail current turn-off loss (tail current loss).
FIG. 2B illustrates tail current loss. As shown in FIG. 2B, the voltage represented by dashed line 225 is the same as that shown in FIG. 2A and the current represented by solid line 220 falls in a manner similar to that shown in FIG. 2A during the period from time t1 to time t2. The size of inductors 115 and 120, and the voltage level across the switch above the DC source voltage 110 determines the rate at which the current decays until time t2. For most bi-polar device, a point (e.g., time t2) is reached at which the switching device itself determines the current decay rate and the current decays at a slower rate thereby increasing the power loss. The power loss between time t2 and time t3 is the tail current loss. The cause and extent of tail current losses are complex, but are generally due to charges stored in the device due to minority carrier injection that occurs with current conduction through most bipolar devices and determined by the voltage and current turn-off conditions and the switching time. For example, for a switching device implementing an IGBT, a lower voltage rating of the switching device for a given voltage at turn-off, results in a lower tail current because there will be fewer stored charges in the device in its saturated, on-state, condition.
The tail current losses are typically much lower than the VI turn-off losses from time t0-time t2. If the VI turn-off loss is reduced and the circuit is switched at substantially higher frequencies, the tail current losses at such higher switching frequencies may be substantially greater than typical VI turn-off losses at a lower frequency. It is for this reason that the tail current losses are considered a significant disadvantage of typical prior art schemes.
VI Turn-On Loss
FIG. 2C illustrates VI turn-on loss. When the switch is turned on, the current across the switch starts to rise as soon as the voltage across the switch begins to fall. As shown in FIG. 2C the current through the switch, represented by solid line 235 does not begin to rise until the voltage, represented by dashed line 240, begins to fall (i.e. at time t1). Therefore from time t0 to time t1 there is no VI turn-on loss. The VI turn-on power loss is represented by hatched area 245 and occurs during the period in which the current across the switch begins to rise and before the voltage falls to zero (e.g., from time t1 to time t2). The VI turn-on loss depends on the rate at which the voltage falls and the rate at which the current rises. If the voltage falls during the same period in which the current rises, then the VI turn-on loss would be similar to that shown in FIG. 2A (though not as great because upon turning off the switch the current doesn't begin to fall until after the voltage has risen above the DC source voltage). If the time required for the current to rise is greater than the time required for the voltage to fall, then the VI turn-on loss is reduced proportionally.
When turning the switch on, if the voltage drops to substantially 0 V before the current starts to rise, then the switch will have no (or negligible) VI turn-on loss. In some soft switching topologies (one or more switching losses not present), discussed more fully below, this condition is the result of the voltage and current timing effects of the circuit topology (e.g., the inductors and capacitors added to the circuit to attain soft switching). This is illustrated in FIG. 2E in which the voltage represented as dashed line 270 falls to near 0 volts at a time (e.g., time t1) prior to the time (e.g., time t2) at which the current represented as solid line 265 begins to rise.
Conductivity Modulation Loss
While the VI turn-on loss applies to circuits implementing a bi-polar device as well as to circuits implementing a field effect transistor (FET), an additional turn-on loss, particular to circuits implementing a bi-polar switching device is the conductivity modulation loss (CM loss), also referred to as conduction modulation loss.
FIG. 2D illustrates the CM loss for a switch implementing a bi-polar device. As shown in FIG. 2D, the current through the switch represented by solid line 250 is the same as that shown in FIG. 2C and the voltage across the switch represented by dashed line 255 falls in a manner similar to that shown in FIG. 2C during the period from time t1 to time t2. From time t2 to time t3 conductivity modulation occurs increasing the turn-on loss. This period is referred to as conductivity modulation time.
In a bipolar device, the n-region (assuming this is the region that is predominantly responsible for blocking voltage in the off state) of the device, just after starting to conduct current, has a higher effective resistance than it has after the current has been flowing for some time. As the current flows the effective resistance of the n-region goes down since minority carriers injected into the n-region (by initial current flow) reduce the n-region resistivity and thus modulate the conductivity. After several microseconds (starting at time t2 in FIG. 2D), the forward voltage drop of the bipolar device will reach its DC forward drop voltage (at time t3 in FIG. 2D) for the current flowing. For example, the forward drop of a bi-polar transistor device at full load (e.g., 100 A) may be 40 V. After the current has been flowing for some time (e.g., 10 microseconds) the forward load may drop to 2 V. The resistance has changed from 0.4 ohms to 0.02 ohms (e.g., the resistance of the device has been modulated as the device conducts current).
The turn-on losses of a switch implementing a bi-polar device are represented by hatched area 260 and occur during the period in which the current through the switch begins to rise and before the voltage falls to zero (e.g., from time t1 to time t3). The CM losses are those losses between time t2 and time t3.
The CM losses are typically much lower than the VI turn-on losses. For example, the CM losses are typically about 20% of the VI turn-on losses. If the VI turn-on loss is reduced and the circuit is switched at substantially higher frequencies, the CM losses at such higher switching frequencies may be substantially greater than typical VI turn-on losses at lower frequencies. It is for this reason that CM losses, like tail current losses described above, are considered a significant disadvantage of typical prior art schemes.
Circuits implementing a bi-polar device and having topologies that result in the voltage dropping to near 0 volts before the current starts to rise will still have CM losses. Such CM losses are illustrated in FIG. 2F in which the voltage represented as dashed line 285 is at or near 0 volts until the current represented as solid line 280 begins to rise at time t1. The voltage rises as the current rises from time t1 to time t2 due to conduction modulation. The voltage then falls to a low voltage at a time t3. The conductivity modulation losses represented by hatched area 290 are incurred from time t1 to time t3.
Capacitive Loss
All switching devices have a capacitance across their power terminals. The capacitance is from the collector to emitter in IGBTs and bi-polar transistors. When the switching device turns on, the capacitance is discharged into the switching device. The energy stored in the capacitor is absorbed in the switching device itself and becomes part of the turn-on switching losses. Typically the energy absorbed is small, even at high frequencies. Soft switching topologies exist that naturally discharge the capacitance before the switching device is turned on with no added circuitry.
Free Wheeling Diode Switching Loss
The switching losses described above did not take into account the sweep out current of the free wheeling diode 125 of FIG. 1 during turn-on. That is, when the switch is off, current is freewheeling through a filter inductor. When the switch is turned on, the current of the diode is reversed until the diode starts to block. At this point, the voltage across the diode increases dramatically resulting in substantial losses in the diode with a corresponding current over shoot in the current in the switching device 105, and significantly more switching loss in the switching device 105, which is not illustrated in FIG. 2C.
Soft-Switching Topologies
There are soft switching topologies that do not have diode turn-on switching loss (e.g., the diode is blocking voltage prior to turn on). For HSM, especially under high voltage conditions, the sweep out current is very high and increases the losses during turn-on to several times that shown in the FIGS. 2A and 2B.
Some attempts have been made to make inverter circuits using so-called "soft switching" mode (SSM) in which the voltage is switched when current through the device is zero, or where the current is switched when voltage across the device is zero. For circuits operating in SSM, one or more of the major switching losses is not present. Soft switching is achieved by using inductors and capacitors to delay current and/or voltage changes. This can result in increased costs and generate undesirable circuit conditions and fault requirements. Moreover, SSM applications reduce either the VI turn-on switching losses or the VI turn-off switching losses, but normally do not address both losses.
Other attempts to address switching losses through varied circuit topologies or modulation schemes have been made but these have not addressed all switching losses in one circuit. For example, some schemes have included loss-reduced snubbers, filters, or additional power devices to assist and/or share current or voltage during switching to reduce VI turn-off losses in the main conduction device, but without addressing VI turn-on losses due to the free wheeling diodes. For example, for low power applications using a metal-oxide semiconductor (MOS) device to control switching in voltage source inverters may employ fast switching and snubbering to reduce VI turn-off losses, but VI turn-on losses and free wheel diode losses remain. CM losses, which are a function of device design, may typically be reduced by modifying the device design, however, this may result in increased switching losses.
Other efforts have been made to address VI turn-on loss, but without addressing VI turn-off loss, diode loss, or other losses such as CM losses and tail current losses incurred with bipolar devices typically employed in high power applications. For such devices, switching losses are typically the determining factor in power handling limitations and in frequency limitations.

Power losses reduction in switching power converters


An LCD TV includes a housing, an LCD screen panel disposed on the front side of the housing, a first mirror disposed on the back side of the housing and a projection-based backlight system disposed in a lower cabinet of the housing, wherein the projection-based backlight system provides polarized light for the LCD screen panel through the first mirror. The projection-based backlight system can provide uniformly polarized light and increase polarization efficiency as well as be easily achieved by using low-cost optical components.

1. Field of the Invention
This invention generally relates to an LCD TV, and more particularly to an LCD TV using a projection-based backlight system.
2. Description of the Related Art
In recent years, liquid crystal displays (LCDs) have been widely used in a variety of applications, including LCD televisions (LCD TVs), portable computers, and vehicle, ship and aircraft instrumentation, due to the advantage of a thin profile and brilliant display. Most LCDs require an illumination source or backlight unit for backlighting LCD panels so that the image displayed on the LCD can be seen by a viewer.
In those applications, LCD TVs are gradually gaining in popularity due to their thin, light features and low power consumption in comparison with conventional cathode ray tube televisions (CRT TVs). An LCD TV comprises an LCD screen panel and a backlight unit placed at the back of the LCD screen panel and configured to light the LCD screen panel so that an image can be formed on the LCD screen panel. In the backlight unit, cold cathode fluorescent lamps (CCFLs) are generally adopted as the light source to provide a uniform backlighting of the LCD screen panel. It is necessary to illuminate the whole surface of the LCD screen panel with the light from a so-called linear light source by such a fluorescent lamp.
In general, as to features of a cold cathode fluorescent lamp (CCFL) used for a light source in an LCD screen panel, its luminance is inversely proportional to its lifetime. That is, if the CCFL is driven with a high current to increase the luminance, its lifespan is reduced, and if the CCFL is driven at a low current to increase its lifetime, it is difficult to obtain high luminance. However, actual commercial products generally require high luminance and a long lifetime concurrently.
Further, when an LCD TV, particularly over 40 inches, is to be manufactured, it is necessary to have a large backlight unit with more numbers of CCFL tubes for supplying sufficient light to the LCD screen panel of the LCD TV. However, the yield for such a large backlight unit having more numbers of CCFL tubes not only has lower yield rate but also has even higher cost. In additions, a more uniformly bright and effectively polarized light for such an LCD TV is not easy to be achieved by these CCFL tubes.
Due to the above shortcomings of the CCFL and its use in an LCD TV, it is needed to provide an LCD TV using a projection-based backlight system so as to solve the above-mentioned problems in the prior art.

LCD TV and projection-based backlight system used therefor


A method of treating hydrolyzate products of hydroxypropylated starch to remove low molecular weight off-flavor compounds is disclosed along with improved bulking agents produced by removal of off-flavor compounds and incorporation of low molecular weight hydrolyzate products.

The present invention relates generally to hydrolyzate products of hydroxypropyl starch which are useful as low calorie bulking agents for use in substitutes for sucrose and other starch hydrolyzate products. More specifically, the invention relates to methods of removing off-flavor components from hydroxypropyl starch hydrolyzate products and improved products resulting therefrom.
Of interest to the present invention is the disclosure of Kesler et al., U.S. Pat. No. 3,505,110 which discloses low calorie sugar products prepared by hydrolysis of hydroxypropylated starch. Kesler discloses methods for preparing hydrolysis products of hydroxypropyl starch which are characterized by a DE of from 1 to 30 and are said to be composed principally of glucose and hydroxypropylated polysaccharides and contain little or no (preferably less than 0.5%) maltose. Kesler discloses what are characterized to be preferred methods for producing the hydrolyzate product comprising hydrolyzing hydroxypropyl starch with a liquefying enzyme to breakup the long chain starch molecules and then treating with a saccharifying enzyme to further hydrolyze the intermediate length molecules to produce glucose (having a degree of polymerization (DP of 1) to the substantial exclusion of maltose (DP 2). While the products of Kesler were characterized as being intended for use as substitutes for ordinary sugar, those products fail to be characterized by bulking properties suitable for use as a sucrose replacer in a wide variety of food products.
Quarles et al., U.S. Pat. No. 5,110,612, the disclosure of which is incorporated by reference, discloses the discovery that hydrolyzate products of hydroxypropyl starch, which comprise greater than about 15% by weight DP 2-6 hydrolyzate polymers and are characterized by a DE value of from about 20 to about 45, have bulking agent properties similar to those of sucrose. Quarles discloses that hydrolyzate products of hydroxypropyl starch produced by conventional acid and/or enzyme hydrolysis are generally unsuitable for use as sucrose substitutes unless they comprise greater than about 15% by weight DP 2-6 hydrolyzate polymers and a DE value greater than about 20. Quarles discloses that hydrolyzate products of hydroxypropylated starch having such elevated levels of "middle range" DP 2-6 starch polymers and accordingly reduced levels of DP 1 monomers and longer chain polymers (DP 7+) exhibit improved properties as food ingredients at any given DE value when compared with hydroxypropyl starch hydrolyzate products characterized by reduced levels of DP 2-6 starch polymers and elevated levels of DP 1 monomers and DP 7+ starch polymers.
Of interest to the present application is the fact that the hydroxypropyl starch hydrolyzate products of Quarles are characterized by a bitter off-flavor which renders those products undesirable for certain food applications.

Method of removing off-flavor components from hydroxypropyl starch hydrolyzate products


A network device is deployed in an in-line fashion, preferably at a data traffic point along a network. Depending on the constraints of data packets in a data packet sequence from a website, the network device is configured to modify some of the data packets or fabricate new data packets to embed the selected data in the data packet sequence. By keeping the headers of the data packets substantially identical, changes to a data packet or addition of a new data packet become transparent to users as well as to the website.

1. Technical Field
The present invention is generally related to the area of data communication between a client and a server over the Internet. Particularly, the present invention is related to techniques for embedding selected data in a data packet sequence. Depending on the constraints of data packets in the data packet sequence, some of the data packets are modified or new data packets are fabricated to embed the selected data in the data packet sequence, all achieved transparently.
2. Description of the Related Art
The advertisement industry penetrates every aspect of our life. Traditional advertising channels including newspapers, radio, and television offer variety of products that can be tailored to virtually any market and satisfy companies of any size. However, they can only provide static content and cannot engage potential customers interactively. Rapid growth of the Internet offers the advertisers a unique opportunity to make interactive advertisement campaigns possible by allowing end users to close the loop, namely inducing users to click on an advertisement being served or linking the users to the actual product.
One early form of advertising over the Internet is the "banner ad," which entails embedding an advertisement into a web page. The banner ad is intended to attract traffic to a website of the advertiser. The advertisement is typically constructed from a high-aspect ratio image, often employing colors, animation or sound to maximize its presence in a webpage. These types of advertisements can be positioned somewhere near the primary content in the webpage (e.g., from a newspaper article or a collection of web portal links). The typical banner ad is purchased in bulk by an advertiser from a publisher of the webpage. Often, the content of the advertising bears no relationship to the interests of the viewer, and therefore makes it unlikely that the viewer may attempt to click through to the website of the advertiser. For example, it is very unlikely that male users would click through any banner ads that show cosmetic promotions for females.
There are two dominant techniques in on-line marketing today. The first one is contextual-based; an advertisement being served is chosen based on the browsing context. In other words, an AD being delivered to the end user is based on the content of a web site being visited. For example, users going to a car site such as "Edmund's car buying guide" will most likely be presented with an automotive advertisement displaying a car or related accessories and services. The second one is behavioral based; an advertisement being served is chosen based on the previous browsing history of a user and is not necessarily related to the content of a site currently being viewed.
The famous website www.google.com is one of the examples based on context. For example, when a user enters a search query on the website, the website delivers advertisements based on the search terms in addition to delivering the requested content responding to the search query. In this case, the content provider (i.e., the search engine website) is the intended recipient of the search query from the user, so the content provider is able to provide targeted advertising based on the search query or the results from the relevant search websites. Thus, the content provider possesses the information necessary to make determinations regarding the content and context from the user.
The entities that own the networks, various mechanisms to facilitate the users to access the Internet and various websites are commonly referred to as "service providers". In various ways, these service providers facilitate movement of packetized information in a computer network. Such service providers typically provide value-added services, such as providing "last-mile" hook-up of the network to the home, office, or mobile product, using networks the service providers own or networks owned by other service providers.
From one perspective, service providers possess the first-hand information of all the packets traveling in their networks. By examining information from content being communicated over the networks, a service provider can examine data packets to inspect for computer viruses, thereby enhancing the security of its network. In some cases, a service provider may even be able to obtain the first-hand knowledge how a subscriber browses the Internet for relevant information. However, the service provider is not being fully equipped to provide commercial information that may be of high interest to its subscribers.
Thus there is a great need for a service provider to be able to deliver targeted commercial information that is of interest to its users. As a service provider is in a business to move data from one location to another location, there is another need for techniques that deliver the targeted commercial information without interrupting or altering the data traffic. As the targeted commercial information is tailored to a user or a group of users in responding to their network activities, there is a need for techniques to deliver such targeted commercial information as closely correlated with the interest of the user(s) as possible.

Network device for embedding data in a data packet sequence


A method of removing residues from an integrated device, in particular residues resulting from processing in HF vapor, is disclosed wherein the fabricated device is exposed to dry water vapor for a period of time sufficient to dissolve the residues in the dry water vapor.

The manufacture of Micro-Electro-Mechanical Systems (MEMS) such as micro-gyroscopes, micro-accelerometers, RF micro-resonators, micro-mirrors, micro-motors, micro-actuators and other such micro-devices integrating very sensitive moving mechanical parts causes a very serious challenge for a number of reasons including the facts that:                a. These very sensitive mechanical parts are typically made of silicon (polysilicon or silicon-germanium);        b. The sacrificial material underlying these mechanical parts to be released is typically silicon oxide;        c. The etch stop layer underlying this silicon oxide sacrificial layer is typically silicon nitride or silicon (polysilicon or silicon-germanium);        d. The mechanical release of the mechanical parts requires the removal of the sacrificial material in liquid or vapor HF-based chemistries;        e. A liquid HF-based solution does not allow one to perform a release in presence of a CMOS compatible Al metallization scheme;        f. A vapor HF-based approach on the other hand leads to undesirable post-release residues that are detrimental to the functionality of the MEMS devices as they block or limit the movements of the released parts.
A method for removing those post vapor HF residues is therefore required in order to allow MEMS released structures to properly move without any potential blocking of the mechanisms. The selected method must not lead to any stiction that could obviously also be detrimental to the functionality of the devices.
A number of prior art solutions exist for removing such residues.
Liquid HF-based Chemistries
Liquid buffered HF (BHF) chemistries and non-buffered HF solutions have been used to mechanically release the sacrificial oxides underlying the silicon-based (polysilicon-based or silicon-germanium-based) structures. The problem with liquid non-buffered-HF solutions is that they quickly attack the Al-based metallization schemes which are CMOS compatible. It has been reported by Witvrouw et al that the etch rate of Al in non-buffered HF chemistries is of 800±600 nm/min. In addition, Ti displays an etch rate of 1200±600 nm/min while a TiN film demonstrates an etch rate of 0.4±0.2 nm/min. Although a TiN film is CMOS compatible, this film is known to have an intrinsic resistivity (˜50-100 μΩ-cm) much higher than the one of Al-based materials (˜2.7 μΩ-cm). TiN therefore may not be suitable for MEMS applications needing a low interconnection resistance.
On the other hand, Witvrouw et al reported slower etch rates for Al, Ti and TiN in buffered HF chemistries. The etch rates demonstrated were of 0.4±0.1 nm/min, 60±30 nm/min and 0.06±0.05 nm/minn for Al, Ti and TiN, respectively. The problem with BHF solutions is that improperly rinsed BHF released wafers will result in an undesirable precipitation of solid ammonium fluorosilicate, (NH4)2SiF6 crystals under the released mechanical parts. This clearly undesirable effect related to the use of BHF solutions is to be prevented in the manufacturing of MEMS devices.
Advanced MEMS devices need to integrate digital and/or analog CMOS control electronics and/or high voltage CMOS drivers capable of performing actuation functions. Since this CMOS electronics needs to be exposed to the release chemicals, the liquid HF-based solutions should not chemically attack the metal-based interconnection of the CMOS systems. Based on the CMOS compatibility requirements, gold (Au), although resistant to liquid HF-based solutions according to Willams et al., could not be considered as it is not CMOS compatible.
Even though a liquid HF-based solution leads to severe issues in presence of metals for CMOS control/actuation electronics, one could circumvent this problem by performing a release prior to the metallization step. This however also involves many potential issues such as:                a. potential metal residues in-between released structures;        b. Sputtering of metal is impossible due to item a above;        c. Al or other metal evaporation means a lift-off approach in conjunction with the metal evaporation techniques. Therefore, the resist strip involves liquid exposure during the remaining steps which would leave the devices prone to stiction; and        d. Low yield and cross-contamination due to potential breakage of devices along the fabrication processes that could contaminate other products.
Such techniques are discussed in A. Witvrouw, B. Du Bois, P. De Moor, A. Verbist, C. Van Hoof, H. Bender and K. Baert, A comparison between wet HF etching and vapor HF etching for sacrificial oxide removal, Proc. SPIE Micromachining and Microfabrication Process Technology VI; September. 2000, Vol. 4174, 2000, pp. 130-141. K. R. Williams, K. Gupta and M. Wasilik, Etch rates for micromachining processing—Part II, Journal of Microelectromechanical Systems, Vol. 12, No. 6, December. 2003, 761-778.
Vapor HF-based Chemistries
Witvrouw et al. showed that Al-based metallization schemes exhibit a low etch rate of 0.03 nm/min in Vapor HF. The etch rates of Ti and TiN are of 0.19±0.02 nm/min and 0.06±0.02 nm/min, respectively. Although the above etch rates are low, one needs to remember that MEMS devices need, in some cases, to have structures released over hundreds of microns. Such excessive etch requirements therefore require excessive etch times therefore leading to an attack of the metal schemes to some extent. On the other hand, it has been demonstrated that the anhydrous HF gas-phase etching conditions used by Ouellet et al. prevent any attack of the metal structures. Even though performing a Vapor HF release in the conditions used by Ouellet et al. prevents the etch of the metal structures, it still potentially leads to the formation of undesirable fluorine-based by-products that are detrimental to the functionality of the devices as they can potentially block or limit the movements of the MEMS-released structures.
Metal-based Residues
It has been noticed by Tong et al. for example in the case of post via etch clean that AlF3 would be formed by the reaction between the gas-phase HF and the Al2O3 which is the native oxide that forms on Al upon exposure to air. The formation of AlF3 would then be formed according to the following equation:Al2O3 (s)+6 HF (g)→2 AlF3 (s)+3 H2O (g)
Although the invention from Ouellet et al described in US patent application No. 2005/0142685 addresses the removal of the toxic ammonium fluorosilicate crystals which can be formed in the presence or absence of metallization schemes on the wafer during the Vapor HF release of the MEMS mechanical structures, it does not cover the contaminants formed due to the presence of metal.
Many others have conducted studies or were granted patents related to Vapor HF processes performed in presence of metal. However, none of them (beside Tong et al.) covered the formation of residues due to the exposure of metallized devices to Vapor HF. The studies and inventions done by other individuals or groups are presented below.
Kim et al.'s invention (US patent application No. US 2004/0018683 A1) is related to the use of Vapor HF performed in presence of metal for storage (memory) devices. However, there is no mention about the potential formation of residues due to such an exposure to a Vapor HF process. In addition, Onishi's invention (U.S. Pat. No. 5,200,361) is related to the use of Vapor HF in order to clean the AlF3 and Al2O3 residues formed during the SF6 plasma etch of vias. However, it is most likely that in that case the AlF3 residues are swept away (since AlF3 is not soluble in acids) during the Vapor HF process. Tsutsui et al. (U.S. Pat. No. 5,922,623) experimented Vapor HF in presence of WSi and AlGaAs without noticing any abnormal issue. Finally, Scheiter et al. (U.S. Pat. No. 5,662,772) also used Vapor HF in presence of Al or other metal but no Post Vapor HF residue formation is discussed.
Beside that, Bergman's inventions (US patent applications No. US 2004/0069320 A1, US 2001/0029965 A1, US 2001/0027799 A1, US 2001/0017143 A1 and patents No. U.S. Pat. No. 6,830,628 B2, U.S. Pat. No. 6,240,933 B1, U.S. Pat. No. 6,240,933 B1, U.S. Pat. No. 6,843,857 B2) all focus on cleaning of Si substrates in order to remove the metallic contaminations. However, there is no discussion related to the formation of residues as such residue formation is most likely minimal. A similar application was discussed by Ma et al. but the formation of residues due to the presence of metal during the vapor phase HF etch is not covered in this publication.
As for Tong et al., they did report the formation of AlF3 from Al2O3 in presence of Vapor HF. However, they perceived AlF3 as an advantage for via resistance purposes. There was therefore no discussion related to the removal of such a by-product. For MEMS applications on the other hand, the removal of this Al fluoride compound is critical for the functionality of the devices.
It is worth mentioning that Chhabra et al were granted a patent (U.S. Pat. No. 5,089,084) in 1992 for the invention of a system in order to perform an in-situ Vapor HF/DI water cascade rinse process. Such a system was intended for Integrated Circuits as opposed to MEMS devices. Even though this invention could allow one to remove the inorganic residues formed during the Vapor HF process in presence of Al (or any other metal), this approach presents many drawbacks for MEMS applications, namely:                a. As this method is intended for CMOS processes, the wafers are not appropriately dried which would in turn lead to released structures of advanced MEMS devices displaying severe stiction problems;        b. Although the "agitation" found in a cascade-type of rinse could allow one to clear the inorganic residues formed during the Vapor HF process, this approach may not be suitable for fragile advanced MEMS devices as it could be prone to breakage due to the harsh mechanical action during a cascade rinse;        c. Such an apparatus proposed by Chhabra et al. does not exhibit any flexibility in terms of water temperature nor the possibility to use a gentle "molecular" excitation of the DI water.
The above techniques are discussed in the following references: CRC Handbook of Chemistry and Physics, Edited by R. C. Weast, CRC Press, Inc., Boca Raton, Fla. 33431, 1979-1980 Edition; N. Chhabra and L. Gibbons, Hydrofluoric acid etcher and cascade rinser, U.S. Pat. No. 5,089,084, Feb. 18, 1992; S. Onishi, Process for preparing a semiconductor device using hydrogen fluoride and nitrogen to remove deposits, U.S. Pat. No. 5,200,361, Apr. 6, 1993; Y. Ma, M. L. Green, L. C. Feldman, J. Sapjeta, K. J. Hanson and T. W. Weidman, Vapor phase SiO2 etching and metallic contamination removal, J. Vac. Sci. Technol. B, Vol. 13, No. 4, July/August 1995, 1460-1465; J. K. Tong, J. S. Martin, T. C. Rogers and D. J. Syverson, Removal of polymeric/silicate residues and reduction of contact resistance for inter-metal via holes by vapor phase HF cleaning, Proceedings of the Fourth International Symposium on Cleaning Technology in Semiconductor Device Manufacturing, Editors R. E. Novak and J. Ruzyllo, 1996, 235-242; T. Scheiter, U. Naeher and C. Hierold, Method for the selective removal of silicon dioxide, U.S. Pat. No. 5,662,772, Sep. 2, 1997; H. Tsutsui, T. Matsumura, H. Oikawa, M. Yokoi, J. Nakamura, H. Sato and J. Mizoe, Hydrogen fluoride vapor phase selective etching methode for fabricating semiconductor devices, U.S. Pat. No. 5,922,623, Jul. 13, 1999; A. Witvrouw, B. Du Bois, P. De Moor, A. Verbist, C. Van Hoof, H. Bender and K. Baert, A comparison between wet HF etching and vapor HF etching for sacrificial oxide removal, Proc. SPIE Micromachining and Microfabrication Process Technology VI; September 2000, Vol. 4174, 2000, pp. 130-141; E. J. Bergman, Methods for cleaning semiconductor surfaces, U.S. Pat. No. 6,240,933 B1, Jun. 5, 2001; E. J. Bergman, Methods for cleaning semiconductor surfaces, US patent application No. US 2001/0017143 A1, Aug. 30, 2001; E. J. Bergman, Methods for cleaning semiconductor surfaces, US patent application No. US 2001/0027799 A1, Oct. 11, 2001; E. J. Bergman, Methods for cleaning semiconductor surfaces, US patent application No. US 2001/0029965 A1, Oct. 18, 2001.; S.-Y. Kim, K.-T. Lee and Y. P. Han, Method of manufacturing storage nodes of a semiconductor memory device using a two-step etching process, US patent application No. US 2004/0018683 A1, Jan. 29, 2004; E. J. Bergman, Methods for cleaning semiconductor surfaces, U.S. patent application No. US 2004/0069320 A1, Apr. 15, 2004; E. J. Bergman, Methods for cleaning semiconductor surfaces, U.S. Pat. No. 6,830,628 B2, Dec. 14, 2004; E. J. Bergman, Methods for cleaning semiconductor surfaces, U.S. Pat. No. 6,843,857 B2, Jan. 18, 2005; and L. Ouellet, G. Migneault and J. Li, A new anhydrous HF release process for MEMS, US patent application 2005/0142685.
Non-metal Based Residues
The reaction between Silicon Nitride (Si3N4) used as an etch stop during the release process and the Vapor HF leads to the formation of ammonium fluorosilicate residues as follow:Si3N4 (s)+16 HF (g)→2(NH4)2SiF6 (s)+SiF4 (g)
This ammonium fluorosilicate residue is thermally unstable and decomposes at a temperature higher than 100° C. as follows:(NH4)2SiF6 (s)→NH4HF2 (s)+SiF4 (g)+NH3 (g)
For the (NH4)2SiF6 and the NH4HF2 compounds, those residues can be eliminated by performing and ex-situ or an in-situ annealing step or by operating the Vapor HF release at a triple point at a pressure of less than 40 Torr and a temperature above 100° C. as reported by Ouellet et al, supra. However, Ouellet et al. did not address the possibility that their invention could leave some fluorine-based residues behind.

Method for removing residues formed during the manufacture of MEMS devices


This invention finds application in the field of liquid distributing devices, and more particularly relates to a sprinkler head device, for example for use in sprinkler systems for distributing liquids or the like. The device comprises a support body to be removably coupled to a sleeve for connection to an external liquid supply line, a convergent nozzle between the body and the sleeve, and a diverter member downstream from the nozzle for diverting flow and sprinkling fluid out. The device further includes main connection means for removably attaching the nozzle to the support body while preventing any accidental separation thereof upon mutual coupling and uncoupling of the sleeve to the body, thereby allowing fast and easy periodic replacement of the nozzle.

Liquid diffuser devices are known to be particularly used in agriculture for conveying a unidirectional water flow into a nozzle and direct it to a plate which distributes it in a plurality of directions.
A diffuser device head as described above is known from international application WO2004/050258, on which the preamble of claim 1 is based.
As shown in FIG. 1, this prior art device has a partly hollow central body C, which may be connected to a liquid feed line by means of a connecting sleeve M. Liquid, whose flow direction is substantially coincident with the axis X′ of the device, passes through the sleeve M and is conveyed into a convergent nozzle U, interposed between the central body C and the sleeve M. Liquid is first accelerated in the nozzle U and then directed to a deflector member, downstream of the nozzle U, which member is composed of the plates D and D′, and is adapted to divert flow to a substantially transverse direction, to disperse it outward.
The nozzle U, which may have different diameters according to desired flow rates, and has to be periodically replaced as needed, is coupled to the sleeve M by snap connection means S, which are designed to hold the nozzle U in an axially locked position with respect to the sleeve M, upon mounting the latter on the central body C or dismounting it therefrom.
In practice, this prior art device has certain recognized drawbacks.
When operating in contaminated environments, with high content of dust and earth, the recess of the snap means S fills up with foreign matter, and is no longer able to effectively hold the nozzle U in position. As a result, undue efforts are required for removing and remounting the various parts, which makes nozzle replacement difficult.
Deterioration of the nozzle and sleeve connection also causes accidental disengagement of the nozzle. As the sleeve is screwed onto the central body, gravity force tends to cause removal of a badly connected nozzle, which is irremediably lost in the environment.


A fuel bundle assembly for a boiling water nuclear reactor comprising a plurality of fuel rods having respective fuel columns therein, and arranged in an ordered array, extending between upper and lower support structures, the plurality of fuel rods enclosed within a hollow, open-ended channel member at least partially enclosed by the open-ended channel member; at least one water rod supported on the lower tie plate and extending upwardly toward the upper tie plate, the at least one water rod having an upward flow path including at least one inlet at a lower end of the upward flow path, and a downward flow path including at least one outlet at a lower end of the downward flow path, the at least one outlet located about midway along the fuel columns within the fuel rods.

This invention relates to boiling water nuclear reactors in general and to fuel bundle assemblies for such reactors in particular.
Boiling Water Reactor (BWR) fuel assemblies include fuel rods and water rods within a flow channel. Water flowing through the many fuel bundles within respective channels provide both coolant and moderator to sustain the nuclear reaction. The moderator function is provided primarily by the higher density liquid. Energy addition along the fuel rods, however, converts some of the water to lower density steam so that its effectiveness as a moderator decreases as the fraction of liquid decreases along the length of the fuel rods. The resultant steam-water flows, referred to as two-phase flows, have higher velocities and cause significant pressure drop along the length of the fuel during typical operation. To reduce this variation in liquid moderator, modem BWR fuel designs include separate flow paths within the fuel bundles which remain filled with liquid (water) over the length of the fuel bundles. These water paths can be configured as one or more round or square tubes (or as cruciform shaped flow passages) generally referred to as water rods. For normal operating conditions, these water rods provide 15% to 20% of the available moderator liquid in BWR fuel bundles.
Current water rod designs provide parallel flow paths through the fuel bundle. They typically include one or more inlet holes near the bottom of the water rods (and the fuel bundle) and one or more outlet holes near the top of the water rods (and the fuel bundle), as illustrated in FIGS. 1 and 2. The placement of these inlet and outlet holes imposes the full bundle pressure drop to drive flow through the water rods. When reactor flow reduces, the pressure difference driving liquid through water rods is also reduced. Current water rods are designed with appropriate inlet flow resistances to maintain very little vapor formation even for such low flow conditions.
A characteristic of such two-phase flow systems is that they can experience flow oscillations under certain conditions of low flow and high power operation. A BWR has a natural tendency to avoid such flow oscillations because the increased steam formed at low flow conditions causes the reactor power to reduce. However, since current water rods are typically designed to remain fill of liquid even at low reactor flow conditions, those water rods limit the natural power reduction at low flow conditions. On the other hand, if the flow restrictions in the water rods are increased to produce significant steam in the water rods at low flow conditions, the current designs result in unfavorable steam in the water rods at normal operation conditions as well.
Two recent water rod designs have been proposed to improve the prior designs mentioned above. One recent design provides varying amounts of steam in the water rod at different reactor flow conditions. This design is intended primarily to enhance spectral shift capability. It utilizes a very small (in cross section) downflow extension tube from the top of the water rod. Thus, water flows upward through a large path and then downward through a small connecting tube for nearly the full length of the fuel before reaching the exit hole. This configuration (illustrated in FIG. 3) has only a short vertical distance between the inlet and outlet holes, with resultant small imposed pressure differential across these holes. For low flow conditions, the downward flow tube is predominantly filled with steam, and the fluid in the upward path is supported like a standpipe with a low pressure differential. The resultant liquid content in the tube is thus quite low, being proportional to the imposed pressure differential. For normal operation, however, the small downflow tube and significant outlet flow restriction combine to severely limit water rod flow. Thus, this design results in significant steam formation in the water rod, with associated unfavorable fuel efficiency, under normal operating conditions.
Another recent water rod design introduces a central standpipe for upflow within a normal water rod design (illustrated in FIG. 4). Using flow restrictions typical of current designs allows for sufficient water rod flow at normal operating conditions to avoid steam formation. For low flow conditions, it was contemplated that the annular region outside of the standpipe would fill with steam when the imposed pressure differential dropped below that necessary to spill liquid over from the top of the standpipe. Unfortunately, analyses have indicated that under such conditions, liquid will flow backward through the upper outlet hole and refill that annular region outside the standpipe (since that region has no bottom drain, it can potentially collect even more liquid than current water rod designs under similar conditions). The only known way to avoid such liquid backflow at the upper outlet hole is to introduce sufficient restriction such that backflow is avoided by the counter flow effects of the escaping vapor. Unfortunately, that amount of flow restriction will again cause unfavorable steam formation in the water rod at normal operating conditions.
The present invention provides a water rod design that is filled with liquid at normal operating conditions but becomes partially filled with steam at low flow conditions. To this end, the water rod(s) are each configured as a siphon tube or siphon water rod (SWR). The newly designed water rods incorporate both an upflow path substantially to the top of the fuel in the fuel rods, followed by a downflow path with outlet holes positioned near the mid-plane of the fuel bundle. This change creates a water rod that operates with a siphon effect, flowing full of liquid at normal operating conditions. This is referred to as the xe2x80x9csiphon modexe2x80x9d of SWR operation. However, at low reactor flow rates, a small amount of vapor formation in the water rod breaks the siphon effect and the water rod transitions to a significant (xcx9c60%) vapor content. This results in the downflow path being virtually filled with vapor, while the upflow path operates as a standpipe with a two-phase mixture. This is referred to as the xe2x80x9cstandpipe modexe2x80x9d of SWR operation.
For some applications, the return or downflow path may be contained within the cross-sectional area of a single water rod. For example, the downflow path could be configured as an internal tube or as an outer annulus as discussed further herein. The siphon water rod may also be configured by interconnecting the tops of two adjacent flow paths. For such an interconnected configuration, it is also possible to incorporate part-length-rods (PLR""s) in the region below the downflow path, as discussed further below.
In all cases, there are two key elements to the disclosed design. First, all of the water rod flow is caused to travel upward from the bottom of the fuel bundle and then downward to the outlet near the fuel bundle mid-plane (i.e., there are no intermediate outlets along the flow path). Second, flow resistances are comparable to current water rod designs such that water rod flows are sufficient to avoid steam content during normal reactor operation(this implies the upflow and downflow portions have similar flow characteristics).
For current water rod designs, water flows are determined by the imposed pressure differential across the inlet and outlet openings minus the fluid density head within the water rod. Thus, current design water rod flow will be zero when the imposed pressure differential just equals the fluid density head in the water rod. For the designs in accordance with this invention, the water rod flow is also driven by the fuel bundle pressure differential imposed between the water rod inlet and outlet openings. However, that imposed pressure differential is significantly lower than current designs (where the outlet is at the top of the water rod) due to the outlet being placed at a much lower elevation in the fuel bundle. However, the net fluid density head working against the flow is also reduced for the siphon water rod, being the net difference between the fluid density heads in the upflow and downflow paths. Thus, when both paths of a siphon water rod are filled with liquid, it is possible to achieve relatively high flows through the water rod even with relatively low imposed pressure differentials. This is the same basic feature utilized for other siphon flow applications (although typical siphon applications make the downflow portion longer than the upflow portion in order to produce net flow even with zero pressure differential between the inlet and outlet openings).
It will thus be appreciated that SWR""s can be designed such that for normal reactor operation, the flow and subcooling entering the water rod are sufficient to maintain liquid water throughout the water rod. Under such circumstances, the siphon water rod provides the same neutron moderation capability as standard water rod designs. However, significant performance difference occurs at reduced reactor flow rates. As the imposed pressure differential decreases, a small amount of steam formation occurs in both current and siphon water rod designs. However, in a siphon water rod such steam formation starts in the downflow path, reducing the fluid density head. That produces a positive feedback by further reducing the water rod flow and causing more steam formation. When sufficient steam formation occurs, the siphon effect is broken and the downflow path quickly fills mostly with steam. Under this condition, the upflow path performs like a standpipe with a density head determined by the imposed pressure differential. Thus, breaking the siphon effect provides the large reduction in water rod liquid content that is needed to improve reactor stability margins at low flow rates.
Accordingly, in its broader aspects, the present invention relates to a fuel bundle assembly for a boiling water nuclear reactor comprising a plurality of fuel rods having respective fuel columns therein, and arranged in an ordered array, extending between upper and lower tie plates, the plurality of fuel rods enclosed within a hollow, open-ended channel member at least partially enclosed by the open-ended channel member; at least one water rod supported on the lower tie plate and extending upwardly toward the upper tie plate, the at least one water rod having an upward flow path including at least one inlet at a lower end of the upward flow path, and a downward flow path including at least one outlet at a lower end of the downward flow path, the at least one outlet located about midway along the fuel columns within the fuel rods.
Other objects and advantages will become apparent from the detailed description which follows.


The coordinates for laying out visual items in two-, three-, or n-dimensional space along an embedded one-manifold or path are calculated and coordinates are generated for placement of the items in a container. A one-manifold may be continuous, discontinuous, be contained entirely within a container or extent beyond a container. The one-manifold may be defined by a set of parameters defining a function, formula or set of points. The container may be a two-dimensional, three-dimensional, or n-dimensional container. Such a mechanism may be employed by a graphics application and may determine the location or positioning of an object or item. The object or item may be one of a set of objects or items. In response to receiving a set of parameters defining a one-manifold, the one-manifold may be embedded within a container. In response to receiving a set of parameters describing aspects of the object or item to be placed within the container, a set of x and y or x, y and z co-ordinates may be generated, which may be sent to a standard graphics interface for display.

In graphics applications, a user needs to be able to see and lay out visual items in a deterministic fashion, very often as an ordered list of items. In some graphics applications, two-dimensional items are automatically laid out based on a layout policy. Typically, items are placed sequentially within a two-dimensional (usually rectangular) container in a left-to-right, right-to-left, top-to-bottom or bottom-to-right pattern. Typical layout policies include flow layout, in which objects (usually rectangular) are placed in a rectangular window from left to right, dock panels, in which objects are laid out vertically and grid layout in which objects are laid out in tabular fashion, the "grid" consisting of cells that are arranged in rows and columns.
When placing objects in three- or higher-dimensional containers, there are fewer preconceptions about how objects "should be" laid out and there are also fewer constraints. There is a need in the art to provide a more flexible way to lay out visual items not only in two-dimensional space but also in three- or higher-dimensional space.

Automatic layout of items along an embedded one-manifold path


A stator of a dynamo-electric machine suppresses short-circuiting attributable to joint portions so as to provide good insulating properties. In a front coil-end group, a turn portion of a first conductor segment and a joint portion of end portions of a second conductor segment are adjacently aligned in a single row in a radial direction, being arrayed in two rows in a circumferential direction. In a rear coil-end group, a joint portion of the end portions of the first conductor segment and the turn portions of the second conductor segment are adjacently arranged in a single row in the radial direction, being arrayed in two rows in the circumferential direction.

This application is based on Application No. 2000-259299, filed in Japan on Aug. 29, 2000, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a stator of a dynamo-electric machine and, more particularly, to a structure of a stator of an alternator driven by an internal combustion engine, such as a structure of a stator of an automotive alternator that can be mounted on a passenger car, a truck, or the like.
2. Description of the Related Art
FIG. 15 is a schematic perspective view showing conductor segments which are constituents of a stator winding in a stator of a conventional automotive alternator disclosed in, for example, Japanese Unexamined Patent Publication No. 11-164506. FIG. 16 is a simplified view showing coil-end groups in the conventional stator of the automotive alternator shown in FIG. 15, and FIG. 17 is a simplified view illustrating the layout of joint portions of the coil-end group in the conventional stator of the automotive alternator shown in FIG. 15.
Referring to FIG. 15, a first conductor segment 331 is formed by bending a copper constituent that is covered with an insulating film and has a rectangular cross section. The first conductor segment 331 is substantially formed into a U shape by connecting a pair of straight portions 331a and 331b at a turn portion 331c. A second conductor segment 332 is formed by bending a copper constituent that is covered with an insulating film and has a rectangular cross section. The second conductor segment 332 is also substantially formed into a U shape by connecting a pair of straight portions 332a and 332b at a turn portion 332c.
In a conventional stator 100, a pair of the first conductor segment 331 and the second conductor segment 332 constructed as set forth above is inserted into a pair of slots of a stator iron core 101 from one end of a the stator iron core, the slots being spaced apart from each other by one magnetic pole pitch. Four straight portions 331a, 332a, 332b, and 331b are accommodated in each slot such that they are aligned in one row in the radial direction or the direction of slot depth. For the convenience of explanation, the positions of the straight portions aligned in each slot will be referred to as a first address, a second address, a third address, and a fourth address, the first address indicating the innermost position. As shown in FIG. 15, an end portion 331d of the first conductor segment 331 extending out from the first address of one slot to the other end of the stator iron core 101 is joined by welding to, for example, an end portion 332d of the second conductor segment 332 extending out from the second address of another slot to the other end of the stator iron core 101, the slot being spaced apart clockwise from the above slot by one magnetic pole pitch. Furthermore, an end portion 332e of the second conductor segment 332 extending out from the third address of one slot to the other end of the stator iron core 101 is joined by welding to, for example, an end portion 331e of the first conductor segment 331 extending out from the fourth address of another slot to the other end of the stator iron core 101, the slot being spaced apart clockwise from the above slot by one magnetic pole pitch. Thus, a lap-wound winding having four turns for each phase is formed. Furthermore, the lap-wound windings for three phases are ac-connected to make up a stator winding 102.
In the stator 100 configured as described above, a coil-end group 102a of the stator winding 102 at one end of the stator iron core 101 is constituted by the first conductor segments 331 and the second conductor segments 332 arranged in two layers in the circumferential direction such that the turn portions 331c of the first conductor segments 331 surround the turn portions 332c of the second conductor segments 332 in an axial direction, as shown in FIG. 16 and FIG. 17. A coil-end group 102b of the stator winding 102 at the other end of the stator iron core is constituted by a joint portion 334a of the end portions 331d and 332d and a joint portion 334b of the end portions 331e and 332e arranged adjacently in two layers in one row in the radial direction, being arrayed in two rows in the circumferential direction, the joint portions 334a and 334b being flush in the axial direction.
However, in the coil-end group 102b of the stator winding 102 of the conventional stator 100, the joint portions 334a and 334b are aligned in two layers adjacently in a single row in the radial direction, being arranged in two rows in the circumferential direction, and the heights of the joint portions 334a and 334b being the same in the axial direction. Hence, the radial interval between the joint portions 334a and 334b from which the insulating film has been lost due to welding is small, presenting a problem of proneness to short-circuiting. There has been another problem in that the joint portions 334a and 334b that are adjacent to each other in the radial direction and have the same height in the axial direction make it difficult to weld them, adversely affecting welding efficiency.
To solve the above problems, an improvement in which the joint portions 334a and 334b are arranged by shifting them in the circumferential direction has been proposed in, for example, Japanese Unexamined Patent Publication No. 2000-166150.
FIG. 18 is a schematic perspective view showing conductor segments of a stator winding in a stator of an improved conventional automotive alternator disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-166150. FIG. 19 is a development partial side view, observed from an inner diameter side, of the stator of the conventional automotive alternator shown in FIG. 18. FIG. 20 is a simplified view illustrating the layout of joint portions in a coil-end group in the stator of the conventional automotive alternator shown in FIG. 18.
In an improved stator 100A, when welding end portions 331d, 332d, 331e, and 332e, the end portions of a first conductor segment 331 and a second conductor segment 332 extending out to the other end of a stator iron core 101 are tilted at different angles so as to cause joint portions 334a and 334b to be shifted in a circumferential direction by xe2x80x9cw,xe2x80x9d as shown in FIG. 18 and FIG. 19.
With this arrangement, a coil-end group 102b of the stator winding 102 at the other end of the stator iron core 101 is configured such that the joint portions 334a and 334b have the same axial height, and are shifted by xe2x80x9cwxe2x80x9d in the circumferential direction and arranged in two rows in the circumferential direction, as shown in FIG. 20.
The stator 100A shares the same construction as that of the stator 100 except that the joint portions 334a and 334b are shifted by xe2x80x9cwxe2x80x9d in the circumferential direction.
Another conventional stator structure employing first, second, and third conductor segments 331, 332, and 333 has been disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-166150. In a stator 100B shown in FIGS. 21 and 22, a coil-end group 102a of a stator winding 102 is constituted by turn portions 331c, 332c, and 333c arranged in the circumferential direction in three layers in the axial direction. A coil-end group 101b is constituted by joint portions 334a, 334b, and 334c which share the same axial height and are arranged in three rows in the circumferential direction so that they are shifted in the circumferential direction by xe2x80x9cwxe2x80x9d.
In the stators 100A and 100B constructed as set forth above, the intervals between the joint portions are longer since the joint portions are shifted in the circumferential direction. This arrangement is expected to suppress the occurrence of short-circuiting between the joint portions that have lost an insulating film due to welding, and also to improve welding efficiency.
According to the stator 100 of the conventional automotive alternator 100, in the coil-end group 102b of the stator winding 102, the joint portions 334a and 334b share the same axial height and adjacently aligned in two layers in one row in the radial direction, being arrayed in two rows in the circumferential direction. This arrangement has been presenting a shortcoming in that the radial interval between the joint portions 334a and 334b that have lost the insulating film due to welding is short, frequently causing short-circuiting. There has been another shortcoming in that the joint portions 334a and 334b, which have the same height in the axial direction and are adjacent to each other in the radial direction, make it difficult to weld them, resulting in poor welding efficiency.
According to the stators 100A and 100B of the conventional automotive alternator, the joint portions 333a and 333b, or the joint portions 333a, 333b, and 333c, have the same height in the axial direction and are arranged in two or three rows in the circumferential direction so that they are shifted by xe2x80x9cwxe2x80x9d in the circumferential direction. With this arrangement, greater intervals can be allowed between the joint portions, so that the chance of short-circuiting between the joint portions can be minimized, permitting improved welding efficiency to be achieved.
However, in the stators 100, 100A, or 100B of the conventional automotive alternator stator, the coil-end group 102b is constructed by joint portions that have the same height in the axial direction and are arranged in two or three rows in the circumferential direction. This arrangement has been posing a problem in that the joint portions may be short-circuited from vibrations, leading to deterioration of insulating properties.
Furthermore, since the joint portions are configured to have the same height in the axial direction, as the number of rows in the circumferential direction increases, the joint portions are more prone to short-circuiting, and weldability deteriorates, making the construction disadvantageous in adding more rows.
Accordingly, the present invention has been made with a view toward solving the above problems, and it is an object of the present invention to provide a stator of a dynamo-electric machine in which joint portions of strands of wire are disposed adjacently to turn portions in a radial direction so as to eliminates the possibility of short-circuiting attributable to the joint portions, thereby allowing improved insulating properties to be achieved.
It is another object of the present invention to provide a stator of a dynamo-electric machine in which joint portions of strands of wire are disposed adjacently to turn portions or other joint portions with respect to the radial direction, and the axial height of the joint portions is made different from that of the turn portions adjoining the joint portions in the radial direction or other joint portions so as to eliminate the possibility of short-circuiting attributable to the joint portions, thereby allowing improved insulating properties and improved weldability to be achieved.
According to one aspect of the present invention, there is provided a stator of a dynamo-electric machine including a stator iron core provided with a plurality of slots arranged in a circumferential direction, and a stator winding constructed by joining a plurality of strands of wire installed in the slots spaced away by a predetermined number of the slots on an end surface of the stator iron core, wherein both coil-end groups of the stator winding are constructed by the joint portions interconnecting the strands of wire on the end surface of the stator iron core and turn portions of the strands of wire that extend out of one slot and enter another slot, the slots being spaced away from each other by a predetermined number of slots, on the end surface of the stator iron core, and on at least one coil-end group of the stator winding, the joint portions are disposed adjacently to the turn portions in the radial direction.
According to another aspect of the present invention, there is provided a stator of a dynamo-electric machine including a stator iron core provided with a plurality of slots arranged in a circumferential direction, and a stator winding constructed by joining a plurality of strands of wire installed in the slots spaced away by a predetermined number of the slots on an end surface of the stator iron core, wherein both coil-end groups of the stator winding are constructed by the joint portions interconnecting the strands of wire on the end surface of the stator iron core and turn portions of the strands of wire that extend out of one slot and enter the other slot, the slots being spaced apart from each other by a predetermined number of slots, on the end surface of the stator iron core, and on at least one coil-end group of the stator winding, the joint portions are disposed adjacently to the turn portions or other joint portions in the radial direction, and the axial height of the joint portions and the axial height of the turn portions adjacent to the joint portions in the radial direction or other joint portions are different.
In a preferred form, on at least one coil-end group of the stator winding, the joint portions, or the joint portions and the turn portions are stacked in three or more layers in one row in the radial direction.
In another preferred form, on at least one coil-end group of the stator winding, the turn portions are positioned adjacently to the joint portions at an inner radial side and an outer radial side of the joint portions and aligned in three layers in one row in the radial direction, and the axial height of the joint portions is greater than the axial height of the turn portions.
In yet another preferred form, an insulating resin is provided to cover the joint portions.
In a further preferred form, the insulating resin is provided between the joint portions adjoining in the radial direction and between the joint portions and the turn portions adjoining in the radial direction.
In another preferred form, varnish is applied to the coil-end groups.
In still another preferred from, on at least one coil-end group, the turn portion is located at an outermost radial position in the radial direction.
In another preferred from, the joint portion located at an outermost radial position is formed to have a lower axial height than the joint portion or the turn portion that is adjacent thereto in the radial direction.


A combined cycle power plant includes a compressor, a first turbine, a second turbine, a first combustor, a second combustor, a heat exchanger and a heat recovery steam generator. A controller operates the combined cycle power plant a first mode wherein compressor air is passed through the heat exchanger before being delivered to the first and second combustors, and exhaust gas from the second turbine is passed to the heat exchanger. The exhaust gas from the second turbine pre-heats the compressor air passing through the heat exchanger to the first and second combustors.

The present invention pertains to the art of combined cycle power plants and, more particularly, to a combined cycle power plant having a reheat gas turbine and an exhaust gas regenerator.
In general, gas turbine engines combust a fuel/air mixture to release heat energy to form a high temperature gas stream that is channeled to a turbine section via a hot gas path. More specifically, a compressor compresses incoming air to a high pressure. The high pressure air is delivered to a combustion chamber to mix with fuel and form a combustible mixture. The combustible mixture is then ignited to form a high pressure, high velocity gas stream that is delivered to a turbine. The turbine converts thermal energy from the high temperature, high velocity gas stream to mechanical energy that rotates a turbine shaft. The turbine shaft is coupled to, and drives, the compressor as well as also other machinery coupled to the turbine such as, an electrical generator.
After converting the thermal energy from the high pressure, high velocity gas stream to mechanical energy, exhaust gases are formed and vented from the turbine. The exhaust gases can either be expelled to ambient air, or used to preheat the combustion chamber and increase turbine efficiency. Optimizing turbine efficiency at various operating conditions, particularly at part load where emissions are typically at high levels is a concern.

Reheat gas and exhaust gas regenerator system for a combined cycle power plant


A class of benzopyranopyrazolyl derivatives is described for use in treating inflammation and inflammation-related disorders. Compounds of particular interest are defined by Formula I ##STR1## wherein A, wherein X, m, n, p, B, R.sup.1, R.sup.2, and R.sup.4 are as described in the specification.

Prostaglandins play a major role in the inflammation process and the inhibition of prostaglandin production, especially production of PGG.sub.2, PGH.sub.2 and PGE.sub.2, has been a common target of antiinflammatory drug discovery. However, common non-steroidal antiinflammatory drugs (NSAIDs) that are active in reducing the prostaglandin-induced pain and swelling associated with the inflammation process are also active in affecting other prostaglandin-regulated processes not associated with the inflammation process. Thus, use of high doses of most common NSAIDs can produce severe side effects, including life threatening ulcers, that limit their therapeutic potential. An alternative to NSAIDs is the use of corticosteroids, which have even more drastic side effects, especially when long term therapy is involved.
Previous NSAIDs have been found to prevent the production of prostaglandins by inhibiting enzymes in the human arachidonic acid/prostaglandin pathway, including the enzyme cyclooxygenase (COX). The recent discovery of an inducible enzyme associated with inflammation (named "cyclooxygenase-2 (COX-2)" or "prostaglandin G/H synthase II") provides a viable target of inhibition which more effectively reduces inflammation and produces fewer and less drastic side effects.
The novel compounds described herein are such safe and also effective antiinflammatory agents. The invention compounds are found to show usefulness in vivo as antiinflammatory agents with minimal side effects. The compounds described herein preferably selectively inhibit cyclooxygenase-2 over cyclooxygenase-1.
Substituted pyrazoles having antiinflammatory activity are described in copending applications 08/160,594 and 08/160,553.
U.S. Pat. No. 3,940,418 to R. Hamilton describes tricyclic 4,5-dihydrobenzg!indazole-3-carboxylic acids as antiinflammatory agents.
U.S. Pat. No. 4,803,193 to Kanda et al, describes spiro3-alkyl-1-aryl1!benzopyrano4,3-c!pyrazole-4(1H),9'-9H!fluorenes as heat sensitive recording matertials.
V. Colota et al (J.Med.Chem., 33, 2646 (1991)) describe tricyclic heteroaramatic systems, including 1-aryl-pyrazolo4,5-c!quinolin-4-ones, 1-aryl-pyrazolo4,5-c!1,8!naphthyridin-4-ones and 1-aryl-1!benzopyrano3,4-d!pyrazol-4-ones for CNS applications. F. Melani et al J.Med.Chem., 29, 291 (1986) also describe 1-phenyl-pyrazolo4,5-c!quinolines for CNS applications.
U.S. Pat. Nos. 4,816,467 and 5,206,258 to Doria et al describe (2-cyano-3-(1,4-dihydro)-1-phenyl-1!benzothiopyrano4,3-c!pyrazol-3-yl)-3 -oxo-propanamides as immunomodulators. G. Doria et al (Farmaco, 46, 843 (1991)) also describe the immunomodulating activity of pyrazolylpropanamides, and specifically ethyl 1-(4-fluorophenyl)-1,4-dihydro-1!benzothiopyrano4,3-c!pyrazole!-3-carbo xylate. British patent 2,227,741 describes related benzopyrano4,3-c!pyrazoles and benzothiopyrano 4,3-c!pyrazoles. European application No. 347,773 similarly describes such fused pyrazole compounds, and specifically .alpha.-cyano-N,1-bis(4-fluorophenyl)-.beta.-oxo-1H-1!benzothieno3,2-c!p yrazole-3-propanamide. U.S. Pat. No. 5,260,328 to Doria et al describes 2-cyano-3-(1,4-dihydro)-1-phenyl-1!benzothiopyrano4,3-c!pyrazol-3-yl)-3- oxo-propanamides for the treatment of rheumatoid arthritis.
U.S. Pat. No. 4,678,499 to Pasteris et al describes 1-aryl-indenopyrazol-4-one-5-sulfonamides as having herbicidal activity. Specifically, 1-phenylindenopyrazol-4-one-5-sulfonamide and 1,4-dihydro-N-(4-methoxy-6-methyl-2-pyrimidinyl)amino!carbonyl!-3-methyl -1-(4-(methylsulfonyl)phenyl!-4-oxo-indeno1,2-c!pyrazole-5-sulfonamide are described.
The invention's benzopyranopyrazolyl derivatives are found to show usefulness in vivo as antiinflammatory agents with minimal side effects.

Benzopyranopyrazolyl derivatives for the treatment of inflammation


The present invention entails a dual shaft putter having a putting head and a pair of shafts extending generally upwardly therefrom. The shafts include lower sections that are secured to the putter head in general transverse alignment. In addition, the shafts include upper parallel sections which lie in a plane, that when extended downwardly, intersects the center of mass of the putting head.

Over the years, the sport of golf has continuously grown in popularity, and at present the sport is attracting new players at record pace. This rapid growth has particularly increased membership in the ranks of novice to intermediate players, which generally desire to improve the their skill level so as to become better players and be more competitive on the golf course.
The nature and numerous subtle facets of golf present the amateur player with a daunting list of skills to build and refine. One aspect of the game in particular, putting, tends to be a problem area for many individuals who play the game. In response to the problematic nature of the putting game for so many golfers, there have been a number of innovations involving putter designs, all with the general intent of improving a player's putting game. One of the most widely accepted theories of putting teaches that it is desirable for the underlying mechanics of the putting stroke to mimic that of a simple mechanical pendulum. Of particular interest and relevance, with regard to this objective, is the advent of dual shafted putters such as those previously disclosed in U.S. Pat. Nos. 5,308,073 and 5,553,858. As discussed in these patents, the fundamental advantage of a dual shafted putter design involves the ease with which it facilitates and promotes a true pendulum type putting stroke. This ability is directly attributable to the fact that the use of a separate shaft for each gripping hand greatly reduces the tendency of the golfer's wrists to break during the normal course of a putting stroke. Hence, the ability to prevent or reduce wrist breaking tendency during a typical putting stroke will likely lead to a more accurate and a generally more consistent putting game.
While the use of dual shafts can certainly reduce the tendency towards wrist breakage, there are other considerations in the design of a putter which can also affect its efficiency. Balance of the club with respect to the putting face, for instance, directly affects the ability of the club to resist rotation upon striking a golf ball, and hence reduces the tendency for the ball to be pushed or pulled from the intended course.
From the perspective of an improvement minded golfer, a putter design which maximizes or optimizes this inherent property of the club which helps resist the wrist breaking tendency during a putting stroke is highly desirable. Therefore, there is and continues to be need for a practical and economical putter which optimally assists the golfer in maintaining proper wrists orientation during a typical putting stroke for the purpose of helping the golfer attain and reap the benefits of a true pendulum type putting swing.