A sports training target system is disclosed. The system includes a target anchor having a support post that includes a slight angle in the forward direction. The system includes a target section having at least one target arm which is rotatably secured to the anchor support post. When a ball is thrown by a pitcher and it strikes the target arm, the target section will partially rotate around the anchor support post. The angle in the support post, together with gravity, will force the taret section back to its original position facing the user.

1. Field of the Invention
This invention relates to a sports training system and, more particularly, to a practice target system and method for developing accurate throwing abilities for example, of a baseball by a baseball pitcher or football by a quarterback.
2. Description of the Related Art
In order to succeed in sports such as baseball and softball, a person typically must possess the ability to accurately throw a ball. Such an ability is particularly necessary for a pitcher in either of these sports. A pitcher must practice for many hours to develop and maintain accurate throwing abilities.
The traditional method of practicing pitching techniques requires both a pitcher and a catcher. The pitcher throws the ball to the catcher who provides a target with his mitt. This method of training can be successful, but it may be difficult for a pitcher to find second player with adequate skills to assist with the training. This severely limits when the pitcher can practice and for how much time he can practice. In addition, this method of practicing pitching lacks accuracy since it requires the catcher to make a subjective determination about whether or not the ball passed within the strike zone while at the same time attempting to catch a ball traveling at a high velocity. Accordingly, there is a need for a device which can allow a pitcher to practice pitching techniques without the aid of another player that can give the pitcher accurate feedback as to his proficiency level.
Once the pitcher's skills becomes more adept, the pitcher must practice not only pitching the ball within the strike zone, but also pitching the ball within a specific section of the strike zone. For example, the pitcher may want to fine tune his or her skills by practicing throwing pitches that are low and inside. Consequently, there is a need for a device which will allow a pitcher to target points within the strike zone so that he can fine tune his pitching skills.
In order to become a proficient pitcher, a player must also practice for many hours. The tedium of repetitive throwing can be particularly difficult to younger players who are just beginning to learn to pitch. It would be desirable to have an apparatus that can keep a player's interest focused on pitching at the target.
Pitchers can be trained wherever there is adequate open space to throw the ball. Training can occur at a baseball field, an empty lot, or even in a backyard. Ideally, a system for training pitchers should be lightweight, yet sturdy, and collapsible for easy transportation and storage.
Many practice targets are limited to a single sport. As a result, the targets can go unused for much of the year. It would be an advantage if a training target system could be used for a variety of sports. For example, similar type of repetitive training and accuracy requirements exist for football quarterbacks as for baseball pitchers. Additionally, target practice for shooting fire arms requires aiming practice to improve firing accuracy. It would be preferable if a sports training target system could be adapted to multiple sports.
For the above reasons, targets which allow a pitcher to practice throwing a ball have been proposed in the related art. Typical examples of training systems of the prior art can be found in U.S. Pat. Nos. 5,803,841 and 5,803,842. However, none of these prior art pitching targets achieve the advantages of the present invention.


The present invention is directed to the effects of applied electric fields on liquid-liquid dispersions. In general, the present invention is directed to the control of phase inversions in liquid-liquid dispersions. Because of polarization and deformation effects, coalescence of aqueous drops is facilitated by the application of electric fields. As a result, with an increase in the applied voltage, the ambivalence region is narrowed and shifted toward higher volume fractions of the dispersed phase. This permits the invention to be used to ensure that the aqueous phase remains continuous, even at a high volume fraction of the organic phase. Additionally, the volume fraction of the organic phase may be increased without causing phase inversion, and may be used to correct a phase inversion which has already occurred. Finally, the invention may be used to enhance mass transfer rates from one phase to another through the use of phase inversions.

The present invention is directed to a method for controlling a phase inversion in a liquid-liquid dispersion. In particular, the present invention is directed to the control of a phase inversion in a liquid-liquid dispersion through the application of electric fields. The present invention is also directed to the enhancement of mass transfer between two liquids in a liquid-liquid dispersion.
Liquid-liquid dispersions are made of two immiscible or partially miscible liquids and are used in many chemical processes. Liquid-liquid dispersions exist in many different areas. For example, in the oil and gas industry, there are oil and water emulsions, which usually have to be separated. Additionally, in the pharmaceutical industry, liquid-liquid dispersions are used for several purposes, including the transfer of a solute from one liquid to another and for polymerization reactions. Finally, liquid-liquid dispersions may be used in chemical separations and clean-up operations to remove a toxin or other undesirable compound from a liquid.
In a liquid-liquid dispersion, there are two liquid immiscible phases, one dispersed as droplets and the other continuous. There are several chemical processes, including, for example, chemical separations and polymerization reactions, in which it is desired to have a high volume fraction of each phase. As one increases the dispersed-phase volume fraction, however, in a liquid-liquid system, there is a risk of phase inversion.
Phase inversion in liquid-liquid dispersions is the phenomenon in which the dispersed phase becomes continuous and the continuous phase becomes dispersed. It is often referred to as a xe2x80x9ccatastrophicxe2x80x9d phenomenon because (i) when phase inversion occurs, the physical properties of the dispersed and continuous phases change abruptly and (ii) inversion back to the initial state of the dispersion involves interruption of the process.
Phase inversion is affected by a variety of factors including the physical properties of both liquid phases in the dispersion, the geometry and materials of the equipment, and the initial and operational conditions. In an aqueous/organic dispersion, if the volume fraction of the organic phase is plotted versus agitation intensity, a region termed the xe2x80x9cambivalence regionxe2x80x9d exists in which either phase can be continuous or dispersed. The initial conditions usually determine which phase (aqueous or organic) will be continuous or dispersed. For example, it has been reported in the literature (Gilchrist et al., 1989) that the liquid phase which is continuous is likely to remain the continuous phase once agitation is initiated. If the volume fraction of the organic phase is greater than the upper bound of the ambivalence region, then the organic phase is continuous and the aqueous is dispersed. Similarly, if the volume fraction of the organic phase is below the lower bound of the ambivalence region, the aqueous phase is continuous and the organic is dispersed.
Effects of physical properties such as density, viscosity, and interfacial surface tension on phase inversion and the ambivalence region have been examined by several investigators (Quinn and Sigloh, 1963; Selker and Sleicher, 1965; Luhning and Sawistowski, 1971; Guilinger et al., 1988; Norato et al., 1998). Effects of equipment geometry and materials of construction have also been examined (Gilchrist et al., 1989; Kumar et al., 1991). A phase-inversion delay time has been investigated by Gilchrist et al. (1989), Kato et al. (1991), and Pacek et al. (1994).
However, these studies have failed to discover a method by which these phase inversions may be stopped, or reversed quickly if the phase inversion has started. As mentioned, phase inversions often are highly undesirable. Typically, when a phase inversion occurs during a process, the process must be shut down, thereby resulting in time and expense for correcting the phase inversion and for the loss in operating time.
Additionally, the prior art has failed to discover methods for controlling phase inversions. These methods would enhance the use of liquid-liquid dispersions as previously discussed by permitting higher volume fractions of the dispersed organic phase without inducing phase inversion. Also, these methods could enhance mass transfer rates from one phase to another to improve the effectiveness of using liquid-liquid dispersions in polymerization reactions and chemical separations.
Some of the prior art has examined the use of applied electric fields in liquid-liquid dispersions. Electric fields have been used to enhance coalescence and removal of small aqueous droplets from an organic continuous phase (e.g., Ptasinski and Kerkhof, 1992). The enhancement of drop coalescence is due to polarization of the conductive droplets in the electric field and mutual attraction (Baygent, et al., 1998). However, while these methods have shown to be effective at separating one liquid from another, they do not teach or suggest a method by which phase inversions may be prevented or reversed.
Accordingly, what is needed is a method of controlling phase inversions in liquid-liquid dispersions to prevent an inversion from occurring or reverse the inversion should one occur. Also what is needed is a method for permitting the increase in the volume fraction of a dispersed organic phase without causing a phase inversion. Finally, what is needed is a method to enhance mass-transfer of a solute from one phase to another in a liquid-liquid dispersion.
The present invention seeks to provide a method of controlling phase inversions in liquid-liquid dispersions to prevent an inversion from occurring. The present invention also seeks to provide a method of correcting a phase inversion without shutting down the ongoing process. Additionally, the present invention also seeks to provide a method of increasing the volume fraction of a dispersed organic phase without causing a phase inversion. Finally, the present invention seeks to provide a method for enhancing mass transfer of a solute from one phase to another in a liquid-liquid dispersion.
In accordance with the present invention, these objects are accomplished by a method for controlling phase inversions in a liquid-liquid dispersion. By being able to control the dispersion, it is possible to prevent a phase inversion from occurring or reverse one that has already occurred. Additionally, by being able to prevent a phase inversion, it is possible to achieve a higher volume of the dispersed phase without causing phase inversion. Finally, by causing and reversing phase inversions in some chemical processes, it is possible to enhance mass transfer of a solute from one phase to another.
The present invention controls phase inversions through the application of an electric field to the liquid-liquid dispersion. The liquid-liquid dispersion will typically comprise a continuous aqueous phase and a dispersed organic phase. The electric field enhances the coalescence efficiency and the coalescence rate of the aqueous phase, thereby causing a continuous aqueous phase to remain continuous, even at higher volume fractions of the dispersed organic phase. Additionally, if a phase inversion has occurred, the electric field will enhance the coalescence of the dispersed aqueous droplets to cause the aqueous phase to become continuous, thereby reversing the phase inversion. Finally, by alternately applying and disengaging the electric field, it is possible to alternately cause and reverse phase inversions within a liquid-liquid dispersion, thereby enhancing mass transfer rates of a solute from one phase to another.
The electric field is applied to the dispersion with the objective of maintaining a dispersion in which the more conductive phase, typically an aqueous phase, is continuous and the less conductive phase, typically organic, is dispersed. This objective is achieved using two electrodes which are introduced into the dispersion. The electrodes are connected to a power supply. An electrical signal applied to the electrodes results in an aqueous-continuous/organic-dispersed dispersion. If initially the dispersion is aqueous-dispersed/organic-continuous, the electric field enhances coalescence of the aqueous droplets, which eventually causes phase inversion. On the other hand, if the dispersion is aqueous-continuous/organic-dispersed, the electric field ensures that the phase inversion will not occur.
If the composition of the dispersion is located above the ambivalence region for the dispersion, then alternately applying and disengaging an electric field will result in alternately causing and reversing a phase inversion within the liquid-liquid dispersion. By turning the electric field on and off, the present invention may be used to better control and optimize processes that involve liquid-liquid dispersions.
These and other objects, features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiments and the appended claims.

Methods to control phase inversions and enhance mass transfer in liquid-liquid dispersions


A self-emptying centrifuge drum has a collecting channel for emptying the drum and a fitting for introducing water into the collecting channel. The drum is rotatable and is hydraulically actuatable by water introduced into the collecting channel through the fitting. The collecting channel rotates with the drum about an axis of rotation and the fitting is stationary and has at least one outlet. A baffle extends up from below the collecting channel and between the collecting channel and the fitting and has a lower portion below the collecting channel and an upper portion extending into an area radially inward of the collecting channel with respect to the axis of rotation. The at least one outlet of the fitting is aimed at the lower portion of the baffle.

The present invention concerns a self-emptying centrifuge drum with at least one valve for releasing solids. The drum is actuated hydraulically by water introduced into a collecting channel through a fitting. The collecting channel rotates with the drum, and the fitting is stationary and has at least one outlet.
A drum of this type is known, from German 3 826 912 C1 for example. The water fitting extends in the form of an enclosed channel into the area radially inside the collecting channel. The spindle that rotates the drum extends through the same area. The inside diameter of the collecting channel is accordingly dictated by the diameter of the spindle and by the radial length of the water fitting in the vicinity of the collecting channel. The stationary fitting must also be far enough from the rotating collecting channel and from the rotating spindle. Since an enclosed channel takes up a lot of space radially with its wall and free cross-section, the inside diameter of the collecting channel must accordingly be longer. The greater the capacity of the collecting channel, however, the weaker the hydraulic pressure generated by the water flowing into the collecting channel. Attempts are accordingly made to keep the diameter of the collecting channel as short as possible.
Making the water fitting a double-walled ring surrounding the spindle in the vicinity of the collecting channel has also been proposed, in German OS 1 532 676 for instance. This makes it possible to decrease the radial length of the water fitting without altering the open cross-section that the water flows through. The same design allows several water outlets in the vicinity of the collecting channel, facilitating the introduction of water into the collecting channel. Water fittings of this type are complicated, however, and always require the collecting channel to be relatively wide. All double-walled water fittings, furthermore, entail the risk of constricting the flow with deposits of dirt or lime.


The present invention relates to a peptide comprising an amino acid sequence identical to or substantially identical to an amino acid sequence represented by SEQ ID NO: 35 and having an ability of binding to a receptor protein comprising an amino acid sequence identical to or substantially identical to an amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 2 or SEQ ID NO: 3, or a precursor thereof, its amide or ester, or a salt thereof.

A galanin is a physiologically active peptide consisting of 29 amino acid residues found for the first time in a porcine small intestine extract [FEBS Lett., 164, pp 124-128 (1983)], and has been identified in various species other than porcine animals, such as mammalian, avian, reptilian and piscine animals. Those reported for their amino acid sequences are a human galanin (FEBS Lett., 283, pp 189-194 (1991)), a bovine galanin (FEBS Lett., 234, pp 400-406 (1988)), a rat galanin (J. Biol. Chem., 262, pp 16755-16758 (1987)), an ovine galanin (Peptides, 12, pp 855-859 (1991)) and the like, and the 15 amino acid residues from the N terminal are preserved among the species.
Known porcine galanins are a precursor protein consisting of 123 amino acid residues (preprogalanin (1-123); Proc. Natl. Acad. Sci. USA, 83, pp 6287-6291 (1986)), a precursor which is longer than a galanin by 9 residues at the N terminal, namely, preprogalanin (24-61) amide, and a preprogalanin (37-61) amide in which 4 residues at the N terminal of a galanin are deleted (Peptides, 13, pp 1055-1060 (1992)).
Known physiological activities of the galanins are an acetylcholin release inhibiting effect in a hippocampus (Brain Research, 709, pp 81-87 (1996)), a feeding center stimulating effect in a hypothalamus (Obesity Research, 3, pp 5735-5895 (1995)), a pituitary hormone release stimulating effect in a pituitary gland (Neuroscience Letter, 75, pp 49-54 (1987); Endocrinology, 134, pp 529-536 (1994); Peptides, 7, pp 51-53, (1986)), an insulin secretion inhibiting effect in a pancreas (Acta Physiol. Scand., 139, pp 591-596 (1990)) and the like, each of which is believed to be exerted via a galanin receptor.
The galanin receptors are classified into three subtypes (GALR1, GALR2, GALR3), and the genes have been cloned for GALR1 in humans, rats and mice (Proc. Natl. Acad. Sci. USA, 90, pp 3845-3849 (1993); J. Mol. Neurosci., 6. pp 33-41 (1995); FEBS Lett., 411, pp 225-230 (1997)), for GALR2 in rats (FEBS Lett., 405, pp 285-290 (1997); Mol. Pharmacol., 52, pp 337-343 (1997); J. Biol. Chem., 272, pp 24612-24616 (1997) and for GALR3 in rats (J. Biol. Chem., 272, pp 31949-31952 (1997). Each of these three galanin receptors has 7 hydrophobic regions (transmembrane domains) characteristic to a G protein-coupled receptor, and is considered to stimulate an intracellular transmission system via an activation of a G protein.
A galanin was proven to bind a galanin receptor of any of these three subtypes. The binding affinity of a galanin is the highest to GALR1, and then next highest to GALR2 and then GALR3, and the affinity to GALR3 is lower by about 10 times than to GALR1 (J. Biol. Chem., 272, 31949-31952, 1997). A galanin was reported also to induce a cAMP production inhibition in a GALR1-expressing cell (Proc. Natl. Acad. Sci., USA 90, 3845-3849, 1993), to induce a cAMP production inhibition in a GALR2-expressing cell (Mol. Pharmacol., 52, pp 337-343 (1997)), and to induce an enhanced inositol-phosphate metabolism and an increased intracellular calcium ion level (J. Biol. Chem., 272, 24612-24616, 1997).
The only intrinsic agonist to a galanin receptor identified so far is a galanin. There is no report of a utilization of an activating reaction of an agonist-dependent G protein (G protein-coupled receptor protein) in a galanin receptor, for example, 35S-labeled guanosine-5′-O-3-thiotriphosphate ([35S]GTPgS) binding increasing reaction (Methods in Enzymology, 237, pp 3-13 (1994)) or a GTP hydrolozation-promoting reaction (Methods in Enzymology, 237, 13-26, 1994) for the purpose of searching for a ligand of a galanin receptor.
It is desired to discover a novel intrinsic agonist which is different from a galanin in the selectivity for (specificity to) a subtype of the galanin receptors.

DNA encoding galanin receptor activating peptide

Abstract: An inventive peptide-encoding DNA or equivalent can be employed in (1) a development of a receptor binding assay system using an expression system of a recombinant receptor protein and a screening for a pharmaceutical candidate compound, and (2) a development of a pharmaceutical having a reduced side effect such as a memory function improving agent, an appetite improving agent, an uterine, renal, prostatic, testicular or skeletal muscle function regulating agent.


A row unit (10) for a cornhead comprises a frame (12), a pair of stalk rolls (14) and a pair of stripper plates (16) forming a stripper gap (20). At least one of the stripper plates (16) is a shiftable stripper plate (16) that is shiftable in a horizontal direction transversely to the longitudinal extent of the stripper gap (20). A spring (32, 32′) has a central helical part (34) winding around a pin (40) connected to the shiftable stripper plate (16) and outer end parts (36) abutting a respective one of two members (44, 54) connected to the frame (12) on opposite sides of the pin (40).

Cornheads are harvesting heads mounted on the front of agricultural harvesting machines, like combines or forage harvesters. During operation, cornheads pull down adjacent rows of corn plants and snap the ears of corn of the plants. The cornheads comprise a number of row units arranged side by side, each of which having a pair of stalk rolls (or one stalk roll interacting with a rigid wall) for pulling the plants down. Above the stalk rolls, stripper plates are mounted, forming a forwardly extending stripper gap, through which the plant is pulled down by the stalk rolls. The distance between the stripper plates is generally adjustable and selected such that the stalk can pass, while the ears are removed from the stalks by the stripper plates and fed by a conveyor, usually a chain conveyor, to a cross auger feeding the ears to the interior of the harvesting machine.
In the prior art, laterally movable stripper plates biased towards another stripper plate by means of a spring with adjustable force have been described, allowing the stripper gap to automatically adjust to the diameter of the plant stalks:
IT 1 291 063 A shows a cornhead row unit with laterally shiftable stripper plates that are coupled at their outer lateral edges by respective pivot links to vertically extending levers. One lever is provided at the front and one at the rear end of the stripper plates. The levers are, beneath the stripper plates, fixed to a forwardly extending shaft connecting both levers. The shaft rotates around its longitudinal horizontal, forward axis.
The rear lever extends down beneath the shaft and is connected to a horizontal helical spring biasing the lever to the outside. This force is transmitted by the lever and the shaft to the stripper plate, which is thus biased towards the other stripper plate. The position of the lever with respect to the spring can be adjusted by a screw thread in order to adjust the spring force. This arrangement is relatively complex and further has the disadvantage that, due the geometry of the mechanism, binding of the stripper plates can occur.
DE 100 12 088 A1 shows another cornhead with spring-biased stripper plates. Helical pressure springs extend in the plane of the stripper plates between the laterally shiftable stripper plates and fixing members at the outer edges of the row unit frame. An adjustment of the spring bias is not provided.
What is needed, therefore, is a cornhead row unit with a stripper plate that is spring-biased by a reliable and uncomplex mechanism. It is an object of this invention to provide such a device in the independent claims of the present application. Further advantages are provided by each of the dependent claims.

Stripper plate bias force adjustment mechanism


An image forming apparatus, including a main body with a first sheet outlet tray and an image forming unit, a feed path configured to guide a sheet from the image forming unit toward the first sheet outlet tray, is provided. The feed path includes a first exit path to guide a sheet toward the first sheet outlet tray and a first duplex path diverging from the feed path to guide a sheet to return to the image forming unit. The main body is attachable with a sheet-exit unit. The sheet-exit unit includes a second sheet outlet tray, a second exit path, and a second duplex path. The second exit path guides a sheet to the second sheet outlet tray. The second exit path is connected with the first exit path when the sheet-exit unit is attached to the main body.

1. Technical Field
An aspect of the present invention relates to an image forming apparatus capable of forming images on both sides of a sheet.
2. Related Art
An image forming apparatus capable of forming images on both sides of a sheet is known. The image forming apparatus may have a sheet-exit path, through which the sheet conveyed out of an image forming unit is ejected to an outlet tray, and a duplex path, which diverges from the sheet-exit path and in which the sheet conveyed out of the image forming apparatus is guided to return to the image forming apparatus. When images are to be formed on both sides of the sheet in the image forming apparatus, first, an image may be formed on one side of the sheet, and the sheet may be conveyed for a predetermined distance toward the outlet tray by an exit roller, which is disposed on the sheet-exit path. Thereafter, rotation of the exit roller may be reversed so that the sheet may be guided back through the duplex path.


The invention provides medical devices, systems and methods for tissue approximation and repair and in particular to reduce mitral regurgitation by means of improved coaptation. The devices, systems and methods of the invention will find use in a variety of therapeutic procedures, including endovascular, minimally-invasive, and open surgical procedures, and can be used in various anatomical regions, including the cardiovascular system, heart, other organs, vessels, and tissues. The invention is particularly useful in those procedures requiring minimally-invasive or endovascular access to remote tissue locations, where the instruments utilized must negotiate long, narrow, and tortuous pathways to the treatment site.

The present invention relates generally to medical methods, devices, and systems. In particular, the present invention relates to methods, devices, and systems for the endovascular, percutaneous or minimally invasive surgical treatment of bodily tissues, such as tissue approximation or valve repair. More particularly, the present invention relates to repair of valves of the heart and venous valves.
Surgical repair of bodily tissues often involves tissue approximation and fastening of such tissues in the approximated arrangement. When repairing valves, tissue approximation includes coapting the leaflets of the valves in a therapeutic arrangement which may then be maintained by fastening or fixing the leaflets. Such coaptation can be used to treat regurgitation which most commonly occurs in the mitral valve.
Mitral valve regurgitation is characterized by retrograde flow from the left ventricle of a heart through an incompetent mitral valve into the left atrium. During a normal cycle of heart contraction (systole), the mitral valve acts as a check valve to prevent flow of oxygenated blood back into the left atrium. In this way, the oxygenated blood is pumped into the aorta through the aortic valve. Regurgitation of the valve can significantly decrease the pumping efficiency of the heart, placing the patient at risk of severe, progressive heart failure.
Mitral valve regurgitation can result from a number of different medical defects in the mitral valve or the left ventricular wall. The valve leaflets, the valve chordae that connect the leaflets to the papillary muscles, and/or the papillary muscles or the left ventricular wall may be damaged or otherwise dysfunctional. Commonly, the valve annulus may be damaged, dilated, or weakened, limiting the ability of the mitral valve to close adequately against the high pressures of the left ventricle during ventricular contraction (systole).
The most common treatments for mitral valve regurgitation rely on valve replacement or repair including leaflet and annulus remodeling, the latter generally referred to as valve annuloplasty. A recent technique for mitral valve repair which relies on suturing adjacent segments of the opposed valve leaflets together is referred to as the "bow-tie" or "edge-to-edge" technique. While all these techniques can be very effective, they usually rely on open heart surgery where the patient's chest is opened, typically via a sternotomy, and the patient placed on cardiopulmonary bypass. The need to both open the chest and place the patient on bypass is traumatic and has associated high mortality and morbidity.
Consequently, alternative and additional methods, devices, and systems for performing the repair of mitral and other cardiac valves have been developed. Such methods, devices, and systems preferably do not require open chest access and are capable of being performed either endovascularly, i.e., using devices which are advanced to the heart from a point in the patient's vasculature remote from the heart or by a minimally invasive approach.
In some instances, however, a variety of challenges are faced in desirably fixating the valve leaflets. For example, it is commonly found in cases of mitral valve regurgitation that a portion of the leaflet is moving out of phase with the other leaflets or portions of the leaflets. This can occur due to an elongation or disconnection of the structures (chordae tendinae) holding the leaflets stable and in synchrony. Such a malfunction can lead to one leaflet or portion of a leaflet to swing or "flail" above the level of healthy coaptation, thereby allowing blood to regurgitate into the right atrium. Such flailing provides a challenge to the practitioner when attempting to fix the leaflets together, particularly via an endoscopic approach. The leaflets may be difficult to grasp, and even when grasped, the leaflets may not be desirably grasped. For example, a leaflet may only be partially grasped rather than having full contact with a grasping element. This may lead to less desirable coaptation and/or eventual slippage of the leaflet from fixation.
The foregoing remarks concerning problems and failures encountered in the mitral valve in the human heart may be made with equal validity concerning the tricuspid valve. This valve has three leaflets rather than two. The three leaflets all meet at a single point near the center of the valve and they demonstrate similar problems of malfunctioning to those shown by the mitral valve.
Therefore, devices, systems and methods are desired which stabilize the tissue, to resist flailing and other movement, prior to and/or during grasping of the tissue. Further, devices, systems and methods are desired which assist in grasping the tissue, enable more desirable coaptation of tissues, provide grasping assessment, and enable the practitioner to determine if desirable grasping of the tissues has occurred, particularly prior to fixation. Further, devices, systems and methods are desired which enable fixation assessment, enabling the practitioner to determine if desirable fixation of the tissues has occurred. These would be useful for repair of tissues in the body other than leaflets and other than heart valves. At least some of these objectives will be met by the embodiments described herein below.


A frequency domain method of processing geophysical data on a computer having massively parallel processors. The method involves assigning data slice partitions to each processor, precomputing a velocity model corresponding to the geophysical data, and migrating the data on each slice within each processor using a one-pass, split wave equation finite difference technique for depth migration and either phase shift or recursive techniques for time migration. A sequence of transforms and transpositions between processors assigned partitions on each frequency slice transforms into the frequency-wavenumber domain and allows the migration calculations to be directly performed by each processor to be independent of each other processor. The transforms and transposes also allow for depth migration error correction and filtering in the frequency-wavenumber domain.

The search for subsurface hydrocarbon deposits typically involves a sequence of data acquisition, analysis, and interpretation procedures. The data acquisition phase involves use of an energy source to generate signals that propagate into the earth and reflect from various subsurface geologic structures. The reflected signals are recorded by a multitude of receivers on or near the surface of the earth, or in an overlying body of water. The received signals, which are often referred to as seismic traces, consist of amplitudes of acoustic energy which vary as a function of time, receiver position, and source position and, most importantly, vary as a function of the physical properties of the structures from which the signals reflect. The data analyst uses these traces along with a geophysical model to develop an image of the subsurface geologic structures.
The analysis phase involves procedures that vary depending on the nature of the geological structure being investigated, and on the characteristics of the dataset itself. In general, however, the purpose of a typical seismic data processing effort is to produce an image of the geologic structure from the recorded data. That image is developed using theoretical and empirical models of the manner in which the signals are transmitted into the earth, attenuated by the subsurface strata, and reflected from the geologic structures. The quality of the final product of the data processing sequence is heavily dependent on the accuracy of these analysis procedures.
The final phase is the interpretation of the analytic results. Specifically, the interpreter's task is to assess the extent to which subsurface hydrocarbon deposits are present, thereby aiding such decisions as whether additional exploratory drilling is warranted or what an optimum hydrocarbon recovery scenario may be. In that assessment, the interpretation of the image involves a variety of different efforts. For example, the interpreter often studies the imaged results to obtain an understanding of the regional subsurface geology. This may involve marking main structural features, such as faults, synclines and anticlines. Thereafter, a preliminary contouring of horizons may be performed. A subsequent step of continuously tracking horizons across the various vertical sections, with correlations of the interpreted faults, may also occur. As is clearly understood in the art, the quality and accuracy of the results of the data analysis step of the seismic sequence have a significant impact on the accuracy and usefulness of the results of this interpretation phase.
In principle, the seismic image can be developed using a three-dimensional geophysical model of seismic wave propagation, thereby facilitating accurate depth and azimuthal scaling of all reflections in the data. Accurately specified reflections greatly simplify data interpretation, since the interpretational focus can be on the nature of the geologic structure involved and not on the accuracy of the image. Unfortunately, three dimensional geophysical models frequently require intolerably long computation times, and seismic analysts are forced to simplify the data processing effort as much as possible to reduce the burdens of both analysis time and cost.
In addition to the 3-D computation challenge, the analyst faces a processing volume challenge. For example, a typical data acquisition exercise may involve hundreds to hundreds of thousands of source locations, with each source location having hundreds of receiver locations. Because each source-receiver pair may make a valuable contribution to the desired output image, the data handling load (i.e., the input/output data transfer demand) can be a burden in itself, independent of the computation burden.
Seismic data analysts have historically used several different approaches to manage these burdens, directly or indirectly. These approaches relate principally to either the manner in which the data acquisition exercise is designed and carried out, or to the assumptions made during the data analysis effort. In both cases, the quality of the output of the data interpretation procedure may be directly affected. These approaches are most easily discussed in conjunction with FIG. 1, which depicts a perspective view of a region 20 of the earth for which a geophysical image is desired. On the surface 18 of the earth are shown a number of shot lines 2 along which the seismic data are acquired. As shown in FIG. 1A, shot lines 2 consist of a sequence of positions at which a seismic source 3 is placed and from which seismic signals 5 are transmitted into the earth. Receivers 4 placed along each line receive the signals from each source position after reflection from various subsurface reflectors 6.
A first method of managing the seismic data burdens discussed above involves careful definition of the region over which the data are acquired. Specifically, use of any available preliminary geologic and geophysical information may facilitate the minimization of the surface area over which seismic data may need to be acquired. Such a minimization will directly reduce the amount of data that is ultimately acquired. Furthermore, similarly careful planning of the spacing between shot lines will optimize the analysis effort by reducing data volume. And finally, optimization of the number of sources and receivers that are used, and of the spacing between adjacent source and receiver positions, will also benefit the data analyst.
None of these efforts can be accomplished without a penalty. For example, relatively wide spacing between shot lines, or between sources and receivers, reduce the resolution of the computed seismic image, thus making interpretation more difficult. In addition, complex geologic features may not be resolvable without relatively close spacing. And finally, certain data acquisition exercises, such as in relatively unexplored areas, do not allow optimization of the surface area over which data is to be acquired. As a result, the data handling burden cannot be entirely eliminated through data acquisition planning.
Methods of minimizing the computational burden are often implemented during data analysis. One commonly invoked technique involves use of a two-dimensional geophysical model. For example, in FIG. 1A, the signals for each source are depicted as traveling in the plane directly beneath the shotline on which the source lies. Thus, the signal is assumed to propagate independent of out-of-plane geologic structures. This simplifying assumption allows use of two dimensional geophysical models in the image generation process, and, as is well known, two dimensional analysis procedures can be much more computationally efficient than three dimensional analysis procedures.
Limitations to the 2-D analysis assumption exist. Geologic structures are rarely, if ever, two dimensional; that assumption may therefore lead to inaccurately specified images. Because little is generally known of the geologic structure being investigated, the analyst usually does not know the extent to which that image is in error. In addition, because each plane is analyzed independently, the interpreter must tie the images for each plane to each of the others by interpolation or other similar interpretative methods if a continuous image across the entire cubic region is desired. Finally, some complex structures, such as faulted regions and salt features, cannot be accurately analyzed merely by use of two dimensional methods.
Because of these and other limits that have long constrained seismic data analysts, the petroleum industry has typically been an early user of newly developed high speed computer hardware. As each new generation of equipment has become available, analysis routines that implement fully three dimensional analysis capabilities have become more commonly used. Nevertheless, it is not uncommon for significant computer times to be involved in complex analyses, often involving weeks or months of actual processing time.
The recent availability of massively parallel processors offers a significant opportunity to seismic data analysts. Massively parallel processors (MPPs) have multiple central processing units (CPUs) which can perform simultaneous computations. By efficient use of these CPUs, the weeks or months previously required for complex analyses can be reduced to a few days, or perhaps a few hours. However, this significant advantage can only be realized if efficient computational algorithms are encoded in the MPP software. Thus, the opportunity MPPs offer seismic data analysts also creates a challenge for the development of suitable computational algorithms that take advantage of the multiple CPUs.
This challenge can be easily discussed by considering the manner in which computational algorithms have most commonly been written for existing seismic analysis routines. Until recently, computers relied on a mode of operation referred to as sequential computing. Sequential computing involves use of analytic routines that perform only a single procedure, or perhaps focus on a single subset of the data or image, at any given time. This is a direct result of a computer having only one CPU. For that reason, the only optimization procedures that can be employed on single CPU computers are those which increase the efficiency of the processing as to the procedure or subset. Because all calculations must ultimately be performed by that single CPU, however, the options for obtaining high performance are innately limited.
On the other hand, the multiple CPU capability of MPPs offers an obvious simultaneous computation advantage. This advantage is that the total time required to solve a computational problem can be reduced by subdividing the work to be done among the various CPUs, provided that the subdivision allows each CPU to perform useful work while the other CPUs are also performing work. Unfortunately, the disadvantage of multiple CPU hardware is that the sequential processing methods that have long been used in software development must be replaced by more appropriate parallelized computing methods. Simply stated, MPPs require that processing methods be developed which make efficient use of the multiple CPU hardware. Ideally, these methods should organize the distribution of work relatively evenly among the processors, and ensure that all processors are performing necessary computations all of the time, rather than awaiting intermediate results from other processors.
The challenge of defining parallelized processing methods, and of optimizing those parallelized methods once defined, is particularly acute in the seismic data processing arena. Seismic data consists generally of a large number of individual traces, each recorded somewhat independently of the other traces. Logically enough, sequential computing methods that require the analytic focus to be placed on a single calculation at a time adapt well to analysis of these independent traces. This is true even though computational bottlenecks may exist. For example, portions of the analytic sequence may require relatively more computation time than other portions, must be completed before other calculations may proceed, or may rely on similar input data as other traces, for example traveltimes. Since no simultaneous computations occur in sequential processing, none of these bottlenecks lead to a reduction in computational efficiency with a single CPU, except as to the total processing time that is required. Except as to that total time requirement, the existence of such computational bottlenecks does not otherwise pose problems for the analyst. To take fall advantage of MPP computing capabilities, however, where the goal is to perform simultaneous processing in all CPUs, methods for optimizing the seismic analysis phase by eliminating such bottlenecks must be developed.
This advantage of an MPP becomes clear by considering the limitation which calculation time places on image region size in single CPU computers. Increasing the size of the image, e.g., by expanding the size of cube 20 in FIG. 1, or increasing the amount of data to be processed, e.g., by adding additional sources 3 and receivers 4 to shotlines 2, increase the total computation. That direct impact on calculation time places a heavy burden on seismic analysts to optimize image size, especially since even small image regions may require weeks of computation time on even the highest speed sequential processing computers. In contrast, efficient processing on MPPs, which may have as many as or more than 256 individual CPUs, should only involve minimally lengthened computation times, since each CPU would assume just a fraction, for example 1/256, of the additional work required by the larger region. This potential for scalability of the image region and the work load required in image generation is a principal benefit of MPPs, a benefit that can only be realized if parallelized seismic processing methods allowing such workload scalability are developed.
Basic considerations for determining efficient parallelized seismic processing methods become evident by reconsidering the above review of the seismic analysis process. As noted, the purpose of seismic analysis is to analyze measured seismic data using geophysical models to develop images of the subsurface. Therefore, each of three principal processing components--data, model, and image--may be considered to be a candidate for distributing computational work among the various processors in an MPP. One option for distributing work among the processors would be to assign different groups of the input seismic trace data to different processors. For example, traces may be grouped by source locations, with different processors being assigned different groups. Similarly, the output image could be subdivided and assigned to different processors. Finally, it may also be possible to subdivide the geophysical model used to generate the output image into groupings that can be assigned to the various processors. (That model is generally considered to be embodied in the arithmetic operations required by the mathematical model that is the subject of the processing effort. For example, in seismic analysis the mathematical model is often based on the wave equation). For example, the data may be transformed into the frequency domain, with individual frequencies assigned to individual processors. It may also be possible to develop combinations of these approaches. For example, groups of processors may be assigned collective responsibility for specific frequencies in the model and all depths in the image, while having individual responsibility for specific horizontal locations in the image. The challenge to the seismic data analyst is to determine methods of subdividing the seismic data, model, and image into components that can be assigned to individual processors in the MPP, thus allowing calculations to be performed in each processor independently of other processors. This subdivision of seismic data analysis into individual components is commonly referred to as seismic decomposition.
One type of MPP has from thousands to tens of thousands of relatively unsophisticated processing elements. In this kind of machine, the processing elements typically perform the same operation on multiple data streams, a Single Instruction, Multiple Data stream (SIMD) machine. An example is the CM2, a product of the Thinking Machines Corporation. These kinds of machines typically lack shared memory, i.e., each processor has its own separate memory unit and the information in the memory cannot be directly accessed by other processors. The individual processors typically have limited computing capability and memory. Because of the large number of processing elements and a lack of shared memory, data transfer between the processing elements is a major bottleneck in efficient utilization of the capability of the machines. Even with sophisticated interconnection techniques, such as in a hypercube arrangement, transfer of data between processors is a major factor in the running time of programs.
Other computers have much more powerful elements in arrays of tens or hundreds. The T3D, a product of Cray Research Corporation, is an example of this kind of machine. Besides having individual processing elements that are much more powerful than those in the CM2, the T3D has fewer of the elements and a physically distributed, logically shared memory. This Multiple Instruction Multiple Data stream (MIMD) machine has different elements performing different operations on different parts of the data at the same time. The reduced number of processing elements means that data does not have to be transferred to as many elements as in a SIMD machine. Because of the increased sophistication and cost of the individual elements and because of their fewer numbers, efficient utilization requires that the load on the processing elements be balanced. An additional factor is that each processing element must accommodate a larger subset of the overall data volume; computations that involve sorting of the data could become more complicated.
U.S. Pat. No. 5,404,296 issued to Moorhead discloses and claims a method for migration on an MPP in which there are a large number of processing elements arranged in a preselected, regular pattern. The data are initially shot-sorted and partitioned into blocks of shots so that the product of the number of receiver positions in the data set and the number of shots in a block equals the total number of processing elements available. Because 3-D seismic data volumes typically contain hundreds of shot and receiver positions, the disclosure and claims are limited to SIMD machines.
One approach that reduces the amount of the 3-D processing is to image a partially processed data set. This is particularly useful when the partial processing operation is computationally simpler than a complete imaging process. For example, prior to migration, the data could be stacked using a conventional Normal Moveout (NMO) velocity analysis. As will be familiar to those knowledgeable in the art, algorithms that perform migration of zero-offset data are computationally less intensive than those that migrate unstacked data. The stacking operation generally improves the signal to noise ratio of the data compared to that of the individual traces. To the extent that the stacked data accurately represents a hypothetical zero-offset trace, the computational burden is reduced.
In U.S. Pat. No. 5,349,527, Pieprzak and Highnam disclose a method for migration of such a data set on a SIMD MPP. The method starts with a 3-D data volume consisting of a time series (vertical axis) of reflection seismic data on a regular rectangular grid (horizontal axes) on the surface of the earth [(t, x, y) data domain]. A Fourier transformation is performed on the reflection seismic data to give a 3-D volume consisting of amplitudes as a function of frequency (vertical axis) on the rectangular surface grid [(.omega., x, y) data domain, where .omega. is the temporal frequency]. The data are partitioned into frequency sub-bands, and within each frequency sub-band, at selected frequencies, data are partitioned into subsets of the rectangular surface grid and assigned to individual processors. This is necessitated by the limited memory capability of the individual processors. The limitations of the individual processors also necessitate a hypercube arrangement of the processors in order to reduce the time involved in data transfer between the processors.
In Pieprzak and Highnam's invention, the subsequent migration is accomplished by an iterative, two-step process. The first step is the downward continuation of a single frequency component over one depth interval. The contributions of all the frequencies are then summed to produce a migrated image at the bottom of the depth interval. The two steps are repeated for successive depth intervals until the maximum depth is reached.
The downward continuation is performed using the McClellan transform method given in Hale, D., 3-D Depth Migration via McClellan Transformations, 56 Geophysics 1778 (1991). The actual implementation is done by means of a convolution filter. As will be known to those familiar with the art, the Hale method has difficulty handling steep dips and the computational burden becomes very heavy at dips greater than 60.degree.. To reduce the computational burden, Pieprzak and Highnam teach the use of a recursive Chebyshev filter for the convolution step. The coefficients of the filter are precomputed from the velocity model of the subsurface and stored redundantly in the local memory of the processing elements. Such an approach is appropriate in SIMD computers where the processing elements need to keep track of only small subgrid of (x, y) points and do not have the capability of computing the filter coefficients "on the fly."
Those knowledgeable in the art recognize that for large problems, frequency domain methods can offer significant computation cost savings. Furthermore, the prior art two-pass migration methods are computationally fast because they perform the migration in the x- and y-direction separately. Pieprzak and Highnam use a one-pass frequency-space domain migration process that is computationally more accurate than the two-pass migration process used in prior art. However, the increased accuracy of the one-pass method comes at the cost of vastly increased computational load. One option for overcoming that increased computational load is to employ frequency-wavenumber migration, which can be significantly faster than frequency-space migration. However, a frequency-wavenumber scheme based on Pieprzak and Highnam's disclosure would be impractical for the reason that the transformation from the spatial domain to the wavenumber domain becomes expensive when each processor has access to only a small portion of the x-y grid.
U.S. Statutory Invention Registration H 482 issued to Berryhill, Gonzalez and Kim in 1988 discloses a method for recursive time migration in the frequency-wavenumber domain. That method assumes that the subsurface of the earth can be modeled by layers in which the velocity is constant. However, the method is inefficient to implement on an MPP because it requires successive Fourier transformations in different directions on a data volume entirely within processor memory, and the geophysical data sets of interest to industry cannot be stored entirely within processor memory.
It would therefore be desirable to have a method that is able to perform a one-pass migration in the frequency-wavenumber domain on an MPP in a cost-effective manner. The present invention satisfies this need.

Method for frequency domain seismic data processing on a massively parallel computer


A request packet generation unit generates a request packet for requesting the distribution of media information. A request packet transmitting unit transmits the request packet. A request response packet receiving unit receives a request response packet corresponding to the request packet from a transmitting device. A request response analysis unit analyzes a request response set in the request response packet. A mode determination unit switches between an operation mode for real-time transmission and that for non-real-time transmission according to device type information, attached to the request response, indicating whether the transmitting device is for real-time transmission or non-real-time transmission. A first receiving unit receives media information in an operation mode for real-time transmission. A second receiving unit receives media information in an operation mode for non-real-time transmission.

When a transmitting device and a receiving device communicate media information such as images, voices and the like with each other on a packet network such as an IP (Internet protocol) network or the like, sometimes real-time transmission and non-real-time transmission are mixed.
In real-time transmission, for example, as illustrated in FIG. 1, image signals obtained by a monitor camera 1305 are encoded by a real-time image distribution device 1303, are transmitted to a real-time image receiving device 1301 as a real-time motion image packet, and are decoded/reproduced. In order to synchronize the clock of image signals to be decoded/reproduced by the real-time image receiving device 1301 with a clock at the time of encoding in the real-time image distribution device 1303, for example, a method using PCR (program clock reference) is adopted. In this method, a clock synchronization packet called PCR is multiplexed on a motion image packet to be transmitted. On the decoding side, a difference between the received PCR data and a system time clock (STC) at the time of reception on the decoding side is calculated. Then, a voltage-controlled crystal oscillator (VCXO) is controlled by this differential value and a reproduction clock is generated. Specifically, in the real-time transmission, the size of a packet receiving buffer on the real-time image receiving device 1301 side is reduced as much as possible by synchronizing the clocks of the real-time image distribution device 1303 (encoder) and the real-time image receiving device 1301 (decoder) and the delay of images can be avoided as much as possible.
However, in non-real-time transmission, as illustrated in FIG. 1, an encoded image signal file accumulated in the storage device of a file distribution server 1304 is read and transmitted using a packet in response to a request from a server distribution image receiving device 1302. The server distribution image receiving device 1302 decodes/reproduces the image signal file transmitted using a packet on the basis of a system clock in its own device. In non-real-time transmission, it is technically difficult to transmit an image signal file at the same timing as that at the time of encoding. Therefore, the server distribution image receiving device 1302 exercises flow control in order to absorb a difference between reproduction timing and transmission timing. In the flow control, when a packet remaining in the packet receiving buffer seems to exceed the buffer size, a transmit stop request packet is transmitted from the server distribution image receiving device 1302 to the file distribution server 1304 and the file distribution server 1304 stops the transmission of an image signal file. Conversely, when no packet seems to be remaining in the packet receiving buffer, a transmit start request packet is transmitted from the server distribution image receiving device 1302 to the file distribution server 1304 and the file distribution server 1304 starts (re-starts) the transmission of an image signal file.
In this case, although the real-time image receiving device 1301 illustrated in FIG. 1 usually receives image signals transmitted from the real-time image distribution device 1303 in real time, there has been a desire for the real-time image receiving device 1301 to also be able to receive image signals transmitted from the real-time image distribution device 1303 not in real time.
In order to realize such mixed reception, it is necessary for the real-time image receiving device 1301 to have a flow control function for non-real-time transmission.
However, when the real-time image receiving device 1301 attempts to receive an image signal file transmitted from the real-time image distribution device 1303 not in real time, there is no prior art capable of discriminating real-time transmission from non-real-time transmission. Therefore, conventionally a flow control function cannot be mounted on the real-time image receiving device 1301.
Therefore, when the real-time image receiving device 1301 receives an image signal file transmitted from the real-time image distribution device 1303 not in real time without flow control, as illustrated in FIG. 1, there is a high possibility that the difference between reproduction timing and transmission timing may increase. As a result, an overflow or underflow of packets occurs in the packet receiving buffer of the real-time image receiving device 1301 and the image signal file cannot be normally received, which is a problem.

Media distribution switching method, receiving device and transmitting device


A Non-Geostationary Satellite Orbit (NGSO) satellite system is described that implements one or more user route tables and a plurality of pre-calculated backbone route tables at its satellites. The user route tables track user connectivity to the satellites, and each of the backbone route tables defines a snapshot of a time-varying backbone topology seen by a particular satellite. During operation, a satellite selects different backbone route tables as the topology changes over time, and receives updates to the user route tables when connectivity changes occur between the users and the satellites. The decoupling of the user route tables from the backbone route tables at the satellite reduces the computational burden on the NGSO system, as the backbone route tables are calculated in advance and the NGSO system is subsequently tasked with a computationally lower burden of performing real-time updates to the user route tables.

NGSO systems utilize constellations of satellites in Low Earth Orbit (LEO) and/or Medium Earth Orbit (MEO) that sweep across the surface of the Earth as they orbit the Earth. This is in contrast to satellites in Geostationary Earth Orbit (GEO), which are stationary with respect to the surface of the Earth as they orbit the Earth.
Due to their relative motion to the surface of the Earth, NGSO satellite systems incur a larger number of ground antenna handovers than GEO satellite systems. Further, unlike handovers in a GEO satellite system that occur due to mobile terminal mobility (e.g., beam handover), NGSO satellite systems are tasked with supporting multiple types of handovers, including intra-orbit handovers (due to the motion of satellites with respect to each other in the same orbital planes), inter-orbit handovers (due to the motion of satellites with respect to each other in different orbital planes), link handovers (due to link outages, which may be due to node and/or link failures), and beam handovers (due to satellite motion, the rotation of the Earth, and/or mobile terminal mobility).
Current solutions for routing in NGSO satellite systems implement link-state routing using Internet Protocol (IP) routers onboard the satellites. Using this approach, a management system constantly calculates and updates the routing information in real time for the entire satellite network when a handover event occurs. As NGSO satellite systems incur a higher number of handovers due to their non-stationary orbits with respect to the surface of the Earth and also due to their relative motion with respect to each other, this type of solution does not scale well to NGSO satellite systems that utilize a large number of satellites. Further, this type of solution is subject to failure when the management system is no longer able, even temporarily, to perform the real-time calculations that the NGSO satellite system relies upon for routing information updates.

Routing for non-geostationary orbit (NGSO) satellite systems


A measured physical quantity calculating part 41 calculates a measurement result-corrected value obtained by correcting a measurement result of a sensor unit 25 by the use of corrected values for the sensor unit 25. Subsequently, a measurement environment estimating part 42 estimates a terrestrial magnetism measurement environment on the basis of at least one measurement result-corrected value. The estimation result is displayed on a display unit 13 by an estimation result display part 43. In this way, the terrestrial magnetism measurement environment is first estimated and then the terrestrial magnetism is measured by the use of the sensor unit 25. That is, it is possible to measure the terrestrial magnetism by the use of a magnetic sensor mounted on a mobile information device after estimating the terrestrial magnetism measurement environment.

The present invention relates to a measurement method and a mobile information device, and more particularly, to a measurement method of measuring a magnetic flux density derived from the terrestrial magnetism by the use of a sensor mounted on a mobile information device and a mobile information device using the measurement method.

Measurement method and mobile information device


A combined atomic force microscope and stylus profilometer adapted to measure critical dimensions on a surface. The stylus profilometer is placed at a first position sufficiently near an edge of a first feature and the atomic force microscope subsequently measures the distance from this first position to the edge. The stylus profilometer is then positioned at a second position sufficiently near an edge of a second feature, measuring the distance from the first position to the second position. The atomic force microscope then measures the distance from the second position to the edge of the second feature.

1. Field of the Invention
This invention relates to semiconductor metrology and, more specifically, to performing measurements of critical dimensions on semiconductor surfaces using a combined stylus profilometer and atomic force microscope.
2. Description of the Relevant Art
An exemplary listing of critical dimensions (CDs) includes the width of a patterned line, the distance between two lines or devices, and the size of a contact. CDs must be monitored to maintain proper device performance. As device sizes continue to decrease at a rapid rate, it has become clear that the ability to carry out quick, inexpensive, reliable, accurate, high-resolution, non-destructive measurements of CDs in the semiconductor industry is crucial.
Measuring CDs is usually done during or after lithography. During lithography, a thin film of photoresist is applied to a semiconductor surface. This surface is then exposed to electromagnetic radiation through a mask which contains a specified pattern consisting of clear and opaque regions. Following exposure, portions of the photoresist are removed during a developing process, producing an image of the mask's pattern onto the substrate. Following development, portions of the substrate no longer covered by photoresist are etched away in order to transfer the mask's pattern onto the semiconductor substrate itself. Many factors occurring during these lithography steps affect the critical dimensions of a semiconductor device. For example, variations in the thickness of the applied photoresist, lamp intensity during the exposure process, and developer concentration all result in variations of semiconductor linewidths. Linewidth variations also occur whenever a line is in the vicinity of a step (a sudden increase in topography). Step-induced changes in linewidth are believed to be caused by at least three different factors including: a) differences in the energy transferred to the photoresist at different photoresist thicknesses, b) light scattering at the edges of the steps, and c) standing wave effects. Because these factors affect CDs greatly, it is important to monitor semiconductor devices quickly and reliably in order to guarantee acceptable performances.
Several different techniques are currently utilized to measure CDs. These include: optical microscopy, scanning electron microscopy, stylus profilometry, atomic force microscopy, and scanning tunneling microscopy. Each of the above will be discussed briefly in turn.
Optical microscopy techniques include the scanning slit technique, video-based acquisition systems, and scanning laser methods. In the scanning slit technique, white light is shined onto a sample, and a photomultiplier tube measures the reflected light passing through a narrow slit which is scanned across the surface of the wafer over a region of interest. The intensity profile output of the photomultiplier tube is used to create a densitometer profile; this profile can then be analyzed using one of several edge-sensing algorithms to generate critical dimension measurements. Video based systems operate on a similar principle. An operator chooses a region of interest on the sample which is illuminated with white light. The light reflected from the region of interest is captured by a video camera which converts an intensity profile of the region into a digital waveform. This waveform is then analyzed to determine the edges of features on the sample and to correspondingly measure critical dimensions of the sample. Scanning laser techniques operate by scanning a laser spot across a region of interest. Typically, a He--Ne laser is focused to a one-micron spot which is scanned across the features of the sample being measured. As with the optical methods discussed above, the light reflected from the sample is then measured to create a topographic profile. Methods for measuring the reflected light profile and for creating a corresponding topographic profile include: using a pair of photodiodes positioned on either side of the laser scan axis, utilizing a confocal scanned microscope and photomultiplier tube, and using laser interferometry techniques. Although resolution has been reported to be 0.25 microns with such optical techniques, several problems limit their capabilities. The largest problem with these optical techniques is their accuracy limitations. Factors contributing to limited accuracy include: limited optical resolution of lenses, non-uniform illumination, problems with coherence, poor mechanical stability, and optical aberrations. Problems associated with the above methods' detection techniques include poor spatial resolution, slow response time, and stability or alignment problems. Although scanning electron microscopy achieves greater accuracy than the above optical methods, it too suffers from some of the same problems as well as introducing new problems in performing CD measurements.
A scanning electron microscope (SEM) operates by creating a beam of electrons which are accelerated to energies ranging from several hundred to several thousand electron volts. The electron beam is focused to a small diameter and scanned across a region of interest of a sample. As the beam strikes the sample's surface, low energy secondary electrons are emitted. The yield of secondary electrons depends on many factors such as the work function of the material, the topography of the sample, and the curvature of the surface. Because different materials may have significantly different work functions, the yield of secondary electrons may be used as a contrast mechanism to distinguish between different materials on a surface. Because changes in topography affect secondary electron yield, one may similarly measure a change in height along the sample's surface. This ability to detect rapid changes in topography is crucial for making CD measurements, for one must, for example, first determine the location of trench edges before measuring the dimensions of the trench. Electron current resulting from the surface-emitted secondary electrons is detected and used to correspondingly control the intensity of pixels on a monitor attached to the SEM. An image of the region being studied is formed by synchronously scanning the electron beam and the screen of the monitor. Even though SEMs can achieve resolution in the range of angstroms, several disadvantages hinder their ability to become an optimal tool for measuring CDs.
SEM weaknesses include the necessity of coating the sample with a conductive layer. A coating must be applied in order to avoid the affects of surface charging which occurs when a high accelerating voltage is used in the SEM. In regards to measuring CDs, the presence of a coating may change the profile of the sample being studied, negatively impacting the measurement obtained. Having to place the sample in a vacuum environment is another drawback to SEM techniques. Vacuum equipment is expensive and may require frequent maintenance; in addition, the vacuum chamber usually limits the size and orientation of the sample which may fit into the SEM. To perform vertical profile CD measurements with an SEM, one must first cleave a sample along the region of interest in order to perform SEM measurements. This requirement of cleaving is greatly limiting, for it means that the measurement technique is time consuming, destructive, and requires the acquired skill of a technician or the presence of an expensive automatic cleaving tool. SEM measurements are also limited in spatial resolution due to e-beam interactions which depend on the materials being measured. For at least these reasons, SEM is currently not an optimal method for CD measurements.
Stylus profilometer techniques are one of the most common methods for measuring CDs. A stylus profilometer is a probe which is drawn across the sample--as the stylus (usually employing a diamond tip) encounters a change in topography, a signal variation based on differential capacitance or inductance is sensed and yields an indication of the step height. Such profilometer techniques are well known in the art and are used in several commercial devices, such as the Sloan Dektak and Tencor Alpha-step machines. Advantages of using a stylus profilometer include ease of use, price, and speed. A major disadvantage, however, is due to the relatively large size of the probe itself. As the stylus is drawn across the surface of the sample, a sudden change in topography due to, for example, a trench cannot be tracked due to the size of the tip and the relatively high scanning speed.
The atomic force microscope (AFM) is a combination of the principles from scanning tunneling microscopy (to be discussed briefly below) and stylus profilometry. In atomic force microscopy, a sharp tip attached to a cantilever is scanned across the surface of a sample. The deflections of the cantilever/tip system are used to measure the small force created by the tip's close proximity to the sample. By using a feedback mechanism to control the separation distance between tip and sample, this small force (<10.sup.-15 Newtons) may be kept constant while scanning across the surface. With a constant force, the tip motion in the z direction will mimic the topography of the sample. Thus, while scanning across the sample, the signal required to maintain a constant cantilever deflection can be recorded, and this signal corresponds to the topography of the scanned surface.
Many different techniques are used for the feedback mechanism in atomic force microscopy. The purpose of each of these differing methods is to accurately measure the cantilever's deflection. With the deflection measured accurately, the feedback mechanism can accurately control the sample/tip distance such that the cantilever deflection remains constant. Early atomic force microscopes used scanning tunneling microscopes to measure the deflection of the cantilever. Since then, there have been many other methods used to detect the deflection of the cantilever/tip system. Usually, optical means are used to measure the cantilever's deflection. For example, a laser may be shined onto the back side of a cantilever and onto an interferometer. The reflected light from the cantilever may interfere with an unreflected beam and produce interference fringes which may be used to determine the deflection of the cantilever. Another way to detect the motions of the cantilever is to shine laser light onto the back of a cantilever and collect the reflected light with a position sensitive detector. Such means are well known in the art--many atomic force manufacturers build equipment employing such means.
Because of their central role, it is important to discuss piezoelectric scanners in regard to atomic force microscopy. Scanners both move along the plane of the sample and allow the tip to track a sample's topography. Most scanners used today are produced from a piezoelectric material made of a lead zirconium titanate (PZT) tube that has been polarized radially. The tube is quartered parallel to its axis and electrodes are placed at each quarter. When a bias is applied between opposite quarters, the tube will extend or contract. When a bias is applied to only one quarter the tube will bend. Therefore, a single tube scanner can be used to both scan the surface and also to control the z-height of the tip, depending on how the applied biases are arranged. An inherent problem with atomic force microscopy scanners (and piezoelectric scanners in general) is their nonlinearity. Although an atomic force microscope's scanner would ideally respond linearly with the applied voltage, scanners exhibit intrinsic non-linearity. A quantitative way to measure the extent of intrinsic nonlinearity is to measure the ratio of the maximum deviation from linearity to the liner extension. In commercial atomic force microscopes, intrinsic nonlinearity can range from two to ten percent. Because scanners do not respond linearly, the features of a sample may appear to have different spacing. Out of the plane of the sample, intrinsic nonlinearity causes slight (2-10%) discrepancies in topographic height measurements. Besides non linearity, atomic force microscopy scanners suffer from problems due to hysterisis, creep, and cross coupling. Hysteresis refers to the following phenomenon: if the voltage applied to a piezo is increased to a certain value and then brought back down to the original voltage, the piezo will not retract along the same path which it extended. In commercial instruments, hysteresis can be as high as 20%. Creep refers to the problem encountered by a scanner when reacting to a swift change in topography. Instead of responding instantly to a sudden change in voltage (brought about by a sudden change in topography), the piezo material responds in two steps. The first of these steps usually occurs in less than a millisecond while the second step can take as long as 100 seconds in some instruments. The effects of creep can be considered by thinking of scanning a symmetric step. As the piezo extends or contracts along the sidewalls of the step, creeping occurs; to maintain the tracking of the step, the feedback system applies a voltage countering the creep. This counter voltage appears as a ridge or shadow of the step. Cross-coupling refers to the fact that as a piezo is scanned across the x-y plane, there exists a z-component of the piezo extension. Thus, the scanner can thought to be moving in an arc. Although these factors may present some problems for making CD measurements, they are diminished by the excellent resolution and accuracy capabilities of an atomic force microscope.
Larger drawbacks to using atomic force microscopes to measure CDs relate to the microscopes' tips. In order to measure CDs with very high resolution, tips sharpened with a focused ion beam are often employed. These high aspect ratio tips allow for accurate measurements of surfaces having rapid changes in topography--such as samples being measured for critical dimensions. Although having their advantages, these tips are extremely fragile and must be replaced often if large scans are performed. Thus, atomic force microscopes present problems relating to reliability and maintenance. In addition, using atomic force microscopes to measure CDs is a very slow process. Although high resolution, the scans can be very slow, reducing throughput. Such reductions in throughput are always sought to be avoided.
As mentioned earlier, scanning tunneling microscopes (STMs) share many qualities with atomic force microscopy. Like AFMs, STMs track the surface of a sample with a sharp tip controlled by piezoelectric scanners. However, STMs, instead of a force gradient, use tunneling current between the tip and the sample as a feedback mechanism. The sharp, metallic tip (ideally the tip is a single atom at the end of a thin wire such as an etched tungsten wire) is brought sufficiently near a sample until a tunneling current is established between the tip and sample. As the tip is scanned across the surface, one may maintain a constant current via a feedback loop (constant current mode) while measuring the z response of the piezo, or the z position of tip may remain constant while the tunneling current is monitored (constant-height mode). Either way, the feedback loop (current or z response of the piezo) is correlated with the topography of the sample. Like AFMs, STMs suffer the same problems inherent with any piezoelectric scanners while scanning over features exhibiting large changes in vertical height. STMs also are not well-suited for CD measurements because the sample being studied must be conductive in order to establish a tunneling current between the tip and sample. Thus, one may not use an STM to scan over the insulators so common in the semiconductor industry. Also, most commercial STMs require a high-vacuum environment in order to achieve adequate resolution. Such vacuum equipment requires much maintenance and can be quite expensive.
It would thus be advantageous have a method and apparatus which would allow for quick, reliable, inexpensive, non-destructive, high-resolution CDs measurements.

Method and apparatus for measuring critical dimensions on a semiconductor surface


A system for playing a digital signal is set forth that includes a receiver receiving a digital signal. System further includes a buffer storing the digital signal in a buffer. A controller determines a read rate and when the signal is interrupted. When the buffer is full, the buffer is read at about the input rate of the buffer. When the buffer is less than full, the buffer is read at a rate less than the input rate when the digital television signal is interrupted.

Satellite television is becoming increasingly popular due to its wide range of programming selection and digital quality. Mobile applications for digital television are also becoming increasingly popular. A mobile application for receiving digital television provides a rotating antenna that can "follow" the satellite as the vehicle moves.
One problem with mobile satellite applications is that obstructions may cause signal interruptions. Such obstructions include tall buildings and tunnels. In current applications, when the signal is interrupted, the display is immediately interrupted and thus the viewer's entertainment experience is diminished.
It would therefore be desirable to provide a method and apparatus for enhancing the viewer's experience and minimize the disruption of the video entertainment.

Method and apparatus for increasing the quality of service for digital video services for mobile reception


A display apparatus including a display driver. The data driver includes a converter to receive and convert image data in digital form into data voltages in analog form, and to provide the data voltages to output buffers. The output buffers receive and buffer the data voltages based on bias voltages generated as part of a feedback path between a bias voltage control circuit and the output buffers. The data voltages are provided to a display part. Before the data voltages output from the output buffers are provided to the display part, the bias voltage control part receives data voltage from the output buffers to count a slew rate of the data voltage, and varies the voltage level of the bias voltage based on the counted result of the slew rate, thereby providing feedback to the output buffers. Accordingly, differences of the slew rate between the data voltages output from the output buffers may be decreased.

The present invention is directed to a display apparatus including a data driver. More particularly, the present invention is directed to a display apparatus including a data driver capable of removing slew rate difference among a plurality of output buffers.
A Liquid Crystal Display (LCD) apparatus, which is one of a family of flat panel display apparatuses, has advantages of being smaller, lighter, shorter, thinner, and a consumer of less power. Recently, the LCD has been used widely in laptop computers, television sets, and mobile phones, among other devices.
In general, an LCD apparatus includes an LCD panel, which displays an image. A data driver and a gate driver drive the LCD panel. An LCD panel includes data lines, which receive a data voltage from the data driver, and gate lines, which receive a gate voltage from the gate driver. Pixel domains are defined in the LCD panel by the data lines and the gate lines. A pixel, which includes a thin film transistor (TFT) and pixel electrode, is arranged in each of the pixel domains. The data driver and the gate driver include chips to be mounted on the LCD panel or on separate films.
The data driver includes output buffers, which are coupled to the data lines in one-to-one correspondence, and buffers data voltage transmitted from a D/A converter to provide the data voltage buffered to the data lines. As described above, since the data voltage which drives each pixel of the LCD panel is output through the output buffers, characteristics of the output buffers may have a significant effect on a display quality of the LCD apparatus. The parameters that determine the characteristics of the output buffers are, for example, slew rate, gain, and phase margin.
The slew rate of the output buffers is an especially important factor that determines the display quality of the LCD apparatus. In other words, when a slew rate difference occurs among the output buffers and among the chips that constitute a data driver, vertical lines appear at a boundary portion between the output buffers and the chips where the slew rate difference occurs, which deteriorates the display quality of the LCD apparatus.

Data driver with bias voltage control circuit and display apparatus having the same


An apparatus and method allowing the changing of image plates or cassettes in an offset printing apparatus without the need to stop the press. Each blanket cylinder is associated with two image cylinders, where each image cylinder carries an associated image plate or cassette. When one of the image cylinders is engaged with the blanket cylinder, thereby transferring an image for printing on the web, the other image cylinder is disengaged from the blanket cylinder. As a result, the other image cylinder is stopped, allowing the image plate or cassette to be changed without the need to stop the entire press operation. After the image plate or cassette is changed on the stopped image cylinder, that image cylinder may be subsequently engaged with the blanket cylinder, while the other image cylinder is disengaged, thereafter allowing that image cylinder to have its image plate or cassette changed. The present invention can include a driving and clutching arrangement which allows an image cylinder which has been stopped for image plate or cassette exchange to be restarted and engaged with the blanket cylinder, while the other image cylinder which was engaged with the blanket cylinder and printing on the web is stopped.

1. Field of the Invention
The present invention relates to the field of offset printing. In particular, the present invention relates to a device for changing image plates in an offset printing press while the press is running.
2. Description of the Prior Art
Offset printing presses are well known in the prior art. In such devices, a blanket cylinder and an image or plate cylinder are used to print on one side of a web of material (e.g., paper) in contact with the blanket cylinder. The blanket cylinder receives an ink image from the image cylinder, and transfers that image to the web of material. The image cylinder usually contains an image plate, upon which is the image to be printed. The image cylinder alternatively can include a cassette of imageable material, which material is pre-imaged or imaged by an imager on the press. Various ink fountains and inker rolls, as well as dampeners, are used to transfer ink to the image plate or imageable material on the image cylinder, to thereby provide ink to the image cylinder for later transfer of the inked image to the blanket cylinder.
In offset printing presses of the prior art, each blanket cylinder is usually associated with a single image cylinder. In such printing presses, when it is time to change the image plate or cassette, either because of maintenance requirements or because of the need to print a new image, it is necessary to stop the press. Because a single image cylinder is used to transfer an image to the blanket cylinder, it is not possible to run the press while the image plate on, or cassette in, the image cylinder is being removed and replaced.
Stopping the press to change an image plate or cassette acts as an interruption to the printing process, slowing down the overall printing process. In addition to the delays caused by changing the image plate or cassette, there are also additional potential delays associated with restarting the press. These delays are the result of the dangers of breaking the web as the printing process is restarted and the press runs up to full speed. Starting and stopping of the press for image plate or cassette changes increases the risks of web breakage, which breakage can introduce additional delays by requiring the web to be re-threaded through the press and for any web scraps to be removed from the press.

Apparatus and method for changing images during operation of a printing press


A system for forming a subterranean wellbore may include a pump and an additive supply. The pump pumps a drilling fluid into the wellbore while also generating a pressure differential that draws an additive across a supply line connected to the additive supply. The drilling fluid may be a gas or a liquid. A method for forming a wellbore may include drilling the wellbore, circulating a drilling fluid in the wellbore using a pump; and supplying an additive to the drilling fluid by flowing the additive across a supply line using a pressure differential generated by the pump. The pump may generate a vacuum pressure at a supply line outlet and/or create a pressure differential in the supply line. The flow of additive across the supply line may be regulated and/or stopped when the pump is not operating.

1. Field of the Disclosure
This disclosure relates generally to additive supply systems for oilfield downhole tools.
2. Description of the Related Art
To obtain hydrocarbons such as oil and gas, boreholes or wellbores are drilled by rotating a drill bit attached to the bottom of a drill string. During drilling, a drilling fluid is supplied under pressure into the drill string. The drilling fluid passes through the drilling assembly and then discharges at the drill bit bottom. The drilling fluid provides lubrication to the drill bit and carries the cuttings of rock and earth produced by the drill bit in drilling the wellbore to the surface. Typically, the costs associated with drilling the wellbore can be substantial. Thus, operators may utilize measures to enhance aspects such as the quality of the wellbore drilled, the reduction in wear and tear on drilling equipment, and time required to drill the wellbore. Some such measures involve the use of additives that control or vary one or more aspects of the downhole environment. These additives may be conveyed into the wellbore along with the drilling fluid.
The present disclosure addresses the need for methods and devices for introducing such additives into the drilling fluid, as well as other needs of the prior art.

This patent is subject to a terminal disclaimer.

Vacuum feed supply system for drilling fluid additives


An input protection circuit protects a multiplexer used in an automotive breakout box for coupling to an electronic control module (ECM) of an automotive vehicle. The input protection circuit includes resistors connected between the input and the multiplexer and a negative feedback amplifier connected to the output of the multiplexer. The negative feedback amplifier provides a virtual ground. Additionally, the inputs to the multiplexer are clamped to within one diode forward voltage drop of electrical ground by diode pairs.

The present invention relates to an automated automotive test system. In particular, the present invention provides input protection for an automated breakout box.
With the advent of integrated circuits, and with the increasing use of sophisticated electronic, electric and electromechanical sensors and control systems in automobiles, the testing and servicing of automobiles has presented ever-increasing challenges. At the present time, many tests of electrical systems, sensors and components of an automobile are made manually by a technician who unplugs a multipin connector between the vehicle's electronic control module (ECM) and the vehicle sensors and controls. The technician makes voltage and resistance measurements between various pins of the connector using a multimeter. The technician making those measurements is required to move the multimeter probe to the appropriate measurement points. It is also necessary to set the multimeter to the proper measuring formula, such as volts or ohms.
This manual testing procedure has many drawbacks. In particular, the technician must follow detailed instructions in order to perform the proper tests. The instructions require that the technician set the proper condition, select the proper test points, read the equipment properly, and compare the reading to the listed tolerances specified in the instructions.
Some test systems have been developed which simplify some of the test operations. These devices use selection switches to select the proper test points. While this helps to some extent, the technician is still required to use the instructions, set the multimeter, and compare readings to the listed tolerances for that measurement.
As the number of electrical systems and sensors increases, the number of possible combinations of points which need testing increases as well. An automated breakout box, therefore, would preferably make use of switching devices to make connections between the testing circuitry and the points to be tested. Analog multiplexers are available which are capable of selecting among a large number of different inputs or outputs.
Analog multiplexers have a maximum input which should not be exceeded. However, signals generated by internal combustion engines typically have a wide dynamic range that can exceed the maximum level which the multiplexer is able to switch. If this occurs, the multiplexer can be burned out.

Automotive test system with input protection


A front-end module for multi-band and multi-mode wireless network system is disclosed. The front-end module includes a diversity switch, two channel-separating devices, a plurality of band pass filters, a plurality of baluns, and a plurality of low pass filters. The number of the band pass filters, the number of the low pass filters, and the number of the baluns are the same as the number of the channels for carrying a radio frequency signal. In addition, all the band pass filters are connected to one channel-separating device while all the low pass filters are connected to the other one, and the baluns are one-on-one connected to the band pass filters.

1. Field of the Invention
The invention relates to a front-end module and, more particularly, to a front-end module-for multi-band and multi-mode wireless network system.
2. Description of the Related Art
Up to the present, the technology for wireless network is mainly divided into two categories. One utilizes a radio wave to make a transmission while the other one utilizes light beam such as infrared light and laser to make a transmission.
The technology utilizing a radio wave is developing in two aspects. One is the blue-tooth technology applied in circumstance of short distance (10 meter), low power consuming (100 mW), and low cost while the other one is the IEEE802.11 technology applied in the office (data transmission rate can be increased up to 54 Mbps and the distance can be lengthen to 100 meter around).
The standard specification for the wireless network system has advanced from IEEE802.11 to IEEE802.11b/g/a since 1997, which indicates that the demand for multi-band and multi-mode is increasing. A wireless network system based on the IEEE802.11 technology always includes a front end module, a base-band processor (defined as PHY), and a media access controller (MAC), and the front end module usually includes a great quantity of passive components such as capacitors, inductances, resistors, filters, and impedance converters. However, these components are usually large and cost one a lot of time to assemble them.
Accordingly, the invention proposes a front-end module that satisfies the need for multi-band and multi-mode, modularization, and miniaturization for a wireless network system. The proposed module is capable of solving the problems of low reliability, high cost, and large volume involved in a conventional front-end module.

Front-end module for multi-band and multi-mode wireless network system