A baseball batting practice device includes a home plate having a center axle extending upright from the home plate, an elongate and radially extending bar having a first end defining a hole through which the center axle extends for the bar to be rotatable about the center axle on the home plate, a bi-directional ratchet mechanism including a toothed disc and a pawl member engageable with each other arranged between the home plate and the bar to allow for angular displacement of the bar with respect to the home plate and a stand mounted to the bar and extending upright therefrom to support a baseball on a top end thereof. The stand includes a slide movably received in a radially extending channel defined in the bar whereby the stand is linearly movable with respect to the center axle in a radial direction.

1. Field of the Invention
The present invention relates generally to a device for practicing batting of baseball, and in particular to a rotary baseball batting practice device wherein the angular location of a stand that supports a baseball to be batted can be changed by means of rotation about a center under the control of a bi-directional ratchet mechanism.
2. The Related Art
Baseball batting practice devices are known. The baseball batting practice device comprises an upright holder that is rotatably mounted to a home plate for supporting and positioning a baseball. The upright holder is selectively retained at different discrete angular positions by means of a rotation mechanism. Such a rotatable construction of the baseball holder allows a player to selectively set a baseball supported by the holder at different angular positions. However, the holder is set at an angular position by having a spring-biased pin removably fit into angularly discrete retention holes defined in the home plate. The operation of moving the holder between different retention holes requires both hands of a user wherein one hand releases the pin and holds the pin in the released condition against the biasing spring and the other hand moves the baseball holder with the pin disengaging from the retention holes. This is very troublesome for the player for he or she must put down the bat before he or she can operate and move the baseball holder.
Thus, it is desired to have a baseball batting practice device that allows for one hand operation to overcome the problems encountered in the prior art.


Disclosed is an orbital cutting apparatus that is capable of freely and selectively controlling forward and backward movement of a plurality of cutting tools, allowing the cutting tools to move forward and backward and to move in an axial direction of a material to be cut so as to enable processing of various shapes as well as cutting and chamfering, and is capable of simultaneously carrying out cutting and chamfering operations for a pipe material or a heavy pipe having a thickness of dozens of mm or more.

In connection with a cutting technique of a pipe, as the size and weight of pipes gradually increase, orbital cutting apparatuses are being developed, in which a cutting tool performs cutting while rotating around and peeling the outer circumference of a fixed pipe little by little by a predetermined depth. Such an orbital cutting apparatus for a pipe is now capable of performing chamfering and cutting by being equipped with both of a cutting tool and a chamfering tool.
As an example of an orbital cutting/chamfering apparatus as described above, an apparatus illustrated in FIGS. 1 and 2 (hereinafter, referred to as "Prior Art 1") has been disclosed. As illustrated in FIGS. 1 and 2, Prior Art 1 includes a main body 10 configured to fix a pipe material P positioned at the center thereof. When the pipe material P passes through any one side (front side) of the main body 10, a rotary body 20 configured to be rotated by an electric motor 15 is coupled to the pipe material P. A cutting tool 31 and a chamfering tool 32 are mounted at the front side of the rotary body 20 to be opposite to each other (or two or more tools to be balanced) such that the cutting tool 31 and the chamfering tool 32 are configured to move vertically (toward the center of the pipe material) by a predetermined depth whenever the rotary body 20 rotates once. Here, the cutting tool 31 and the chamfering tool 32 are mounted on a block 40, which is guided to be capable of reciprocating toward the center of the pipe material P on the front face of the rotary body 20, and the blocks 40 are screw-coupled to a rotary shaft 50, of which the upper end is formed with a gear 51. Accordingly, whenever the gear 51 comes in contact with a finger stop 60 protruding from the main body 10, the rotary shaft 50 vertically moves the block 40 by a pitch corresponding to the rotating angle of the gear 51 so as to make the cutting tool 31 and the chamfering tool 32 move forward to the center of the pipe material P.
As described above, Prior Art 1 is related to an apparatus that is capable of cutting the pipe material or simultaneously cutting and chamfering the pipe material by causing the cutting tool 31 and the chamfering tool 32 to dig into the pipe material P by a predetermined depth whenever the cutting tool 31 and the chamfering tool 32 revolve around the pipe material one round, but is a limited technique that cannot arbitrarily control the movements of the cutting tool and the chamfering tool. That is, Prior Art 1 cannot arbitrarily adjust the cutting tool and the chamfering tool while the rotary body 20 is being moved.
When the cutting tool and the chamfering tool cannot be adjusted, it means that cutting conditions cannot be changed depending on the size, material, kind, or the like of a workpiece. This may naturally deteriorate the cutting efficiency, and may also disable cutting itself. In addition, there will be a trouble in that in order to return the cutting tool and the chamfering tool to the original positions thereof after the cutting operation is completed, it is necessary to reversely rotate the rotary body again or to perform an operation for returning the rotary body to the original position thereof using a separate reverse rotating means.
In addition, in the case of the cutting/chamfering apparatus of Prior Art 1, it is difficult to anticipate when the cutting tool and/or the chamfering tool become dull or are damaged so that workpieces may be frequently damaged due to the damage of the cutting tool and/or the chamfering tool. That is, in a case where a tool is in a dull or damaged state in the cutting/chamfering apparatus of Prior Art 1, the tool continuously digs into the workpiece by the rotation of the gear even though the workpiece is in a non-cut state due to the abnormal condition of the tool. As this state is repeated, load increases between the tool and the workpiece so that the load may cause the entire tool or the workpiece to be damaged.
In addition, the cutting/chamfering apparatus has problems in that it is impossible to process various shapes, it is impossible to cut a pipe material having a thickness that is thicker than a predetermined thickness, a damage may be caused by a collision between the gear and the finger stop, a cutting depth may not be adjusted, and a chamfering edge should be frequently replaced depending on a chamfering angle and shape. However, the problems are not solved.
These problems will be described in more detail with reference to a case in which Prior Art 1 processes a pipe material in an operating sequence as illustrated FIG. 3. That is, the cutting tool 31 and the chamfering tool 32 dig into the pipe material P as illustrated in the first drawing in FIG. 3, and processing is performed while causing the cutting tool 31 and the chamfering tool 32 to gradually and more deeply dig into the pipe material P in the order as illustrated in the second to fourth drawings so that the pipe material P is chamfered simultaneously with being cut. Accordingly, the processing of the pipe material by Prior Art 1 has a limit in that the processing capable of being performed by Prior Art 1 is confined to cutting as illustrated in FIG. 4A and cutting and one side chamfering as illustrated in FIG. 4B.
As illustrated in FIG. 5, it is natural that the cutting tool 31 for use in cutting a pipe material should have a length that is long as compared to the thickness t of a pipe material to be cut in order to cut the pipe material. However, when the length L of the cutting tool is increased in order to cut a pipe material having a thickness t of dozens of mm or more, the cutting tool may not withstand the force applied thereto and may thus be easily damaged.
In addition, as illustrated in FIG. 6, it is natural that the length lb of the edge of the chamfering tool 32 for improving and processing a cut surface of a pipe material should be longer than the length of an inclined surface of the pipe material. However, as illustrated in FIG. 7, since the length of the chamfering edge, lb, is substantially longer than the length of the cutting edge, lc, the chamfering edge should also endure considerable load corresponding to a force applied thereto.
In addition, it may be understood that Prior Art 1 is operated in a manner in which the cutting tool cuts the central portion by a predetermined value per every one rotation, and the load received when performing cutting and the load received when performing chamfering are different from each other, i.e., the cutting resistance P variably acts. Here, the cutting resistance P is determined by a specific cutting resistance Ks according to the quality of a material to be cut, a cut width l, and a processed depth dp, and may be expressed by an equation as follows.P=Ks×l×dp
Accordingly, as illustrated in FIG. 7B, at the time of using a cutting tip for cutting, a pitch may be calculated by estimating the cut width lc and the processed depth dp while neglecting the specific cutting resistance according to the quality of the material to be cut. However, at the time of chamfering, as illustrated in FIG. 7A, because the cut width lb varies depending on the thickness of the pipe material, t, it is difficult to calculate a pitch value (a depth to be processed per one rotation) suitable for chamfering. Due to this reason, the chamfering may not satisfy various processing requirements, which makes commercialization difficult, and the chamfering tool is frequently damaged which may also cause a problem in mechanical design to overcome it.
A gear is engaged with a finger stop such that whenever the gear rotates by a predetermined angle, the cutting tool and the chamfering tool are lowered to perform cutting by a predetermined depth. When it is intended to cut and chamfer a pipe material having a thickness of dozens of mm, there is a problem in that the gear, the accessories below the gear, the finger stop, and so on may be damaged as the gear and the finger stop collide with each other hundreds of times. For example, assuming that the gear has five protrusions, the pitch at the time when the gear makes one rotation is 1 mm, and the thickness of the pipe is 20 mm, the finger stop and the gear will collide with each other 5 times in order to cut 1 mm from the pipe material, and will collide with each other by 100 times in order to process 200 mm. When such a processing is performed 100 times per day, the collision will occur 10,000 times, and when such a processing is performed for 100 days, the collision will occur 1,000,000 times. When such collision occurs during a high speed rotation, a considerably high impulse will be generated, which will exert a very harmful influence on the endurance of the apparatus.
In addition, in Prior Art 1, since the cutting is performed by a predetermined depth only when the finger stop is engaged with the gear, it is impossible to arbitrarily adjust the cutting depth and the range of choice of a workpiece is narrowed. That is, depending on the material of the workpiece or the kind of a tool, the cutting speed, the cutting depth, and so on are determined. However, Prior Art 1 may have a problem in that it cannot adjust the processing conditions even if such processing conditions exist.
In addition, the chamfering angle may vary depending on the kind and design of the pipe material. However, the Prior Art 1 has an inconvenience in that it is necessary to replace the chamfering tool in order to change the chamfering angle.
In order to overcome the problems of the prior art as described above, the inventor of the present application has researched measures that are capable of freely controlling forward and backward movements of a cutting tool, allowing the cutting tool to move not only in a direction perpendicular to a circular material to be cut, but also in an axial direction of the material to be cut so as to enable the processing of various shapes as well as cutting and chamfering, and are capable of simultaneously carrying out cutting and chamfering operations for a heavy pipe, such as a pipe material or a hard-to-cut material, having a thickness of dozens of mm or more.
In particular, the inventor has researched various measures for a method that is capable of freely controlling the movement of a tool within a rotary body. As a result, a first control method based on wireless communication, a second control method based on centrifugal force, and a third method based on hydraulic pressure have been proposed, and finally a control method using a rotational speed ratio have been proposed.
A tool control method based on wireless communication, which is the first proposed technique, is proposed by the applicant and the inventor of the present application in Korean Patent No. 1407327 (registered on Jun. 9, 2014), which is incorporated by reference, a tool control method based on centrifugal force, which is the second proposed technique, is also proposed in Korean Patent No. 1407328 (registered on Jun. 9, 2014), which is incorporated by reference, a tool control method based on hydraulic pressure, which is the third proposed technique, is proposed in Korean Patent No. 1415513 (registered on Jun. 30, 2014), which is incorporated by reference, and a tool control method using a rotational speed ratio is proposed in unpublished Korean Patent Application No. 2014-0066480 (filed on May 30, 2014), which is incorporated by reference.
Representative related techniques for the tool control method using a rotational speed ratio for a plurality of wheels, which is the fourth proposed technique, are as follows.
Prior Art 2: U.S. Pat. No. 5,605,083 (published on Feb. 25, 1997) (title of the invention: pipe cutting apparatus with differential speed rotatable ring cutter actuation), which is incorporated by reference.
Prior Art 3: JP Patent Laid-Open Publication No. 2001-096421 (published on Apr. 10, 2001) (title of the invention: pipe cutting apparatus), which is incorporated by reference.
Prior Art 4: JP Patent Laid-Open Publication No. 2003-117720 (published on Apr. 23, 2003) (title of the invention: pipe cutting apparatus), which is incorporated by reference.
Prior Art 5: EP 2085169A (published on Jul. 11, 2012) (title of the invention: pipe cut-off apparatus), which is incorporated by reference.
Prior Arts 2 and 5 were filed in the name of the invention to propose a method of controlling a movement of a tool according to a speed ratio between a rotary body and a ring gear by mounting the rotary body on the tool and then installing the ring gear, which is relatively rotated in relation to the rotary body, to be interlocked with the tool.
Prior Art 3 proposes a method of controlling a movement of a tool by mounting a plurality of planet gears within a rotary body, mounting a tool on the planet gears, and then causing the rotation of the planet gears to be relatively rotated in relation to the planet gears.
In addition, Prior Art 4 proposes a method of controlling a movement of a tool according to whether the tool is meshed with a specific gear in a two-stage composite gear by mounting a tool on a rotary body and then installing the two-stage composite gear interlocked with the tool within the rotary body.
In sum, it has been found that the prior arts related to the rotational speed ratio are provide with a rotary boy and a relatively rotated control wheel in order to control a vertical movement or a pivotal movement of a tool mounted on a rotary body, and a technique, which was intended to be proposed by the inventor, has already been known by the prior arts.
The items to be newly proposed by the inventor in relation to a tool control method using a rotational speed ratio in an orbital pipe cutting apparatus is related to a technique in which two or more tools are mounted on a rotary body, and then the two or more tools are selectively controlled. Prior Arts 2 to 5 cannot individually control one or more tools neither selectively nor independently.

Orbital cutting apparatus capable of freely and selectively controlling plurality of cutting tools within rotating body by using rotational speed ratio


A method for optically transferring a lithographic pattern corresponding to an integrated circuit utilizing a high transmission attenuated phase-shift mask onto a semiconductor substrate by use of an optical exposure tool. The method comprising the steps of generating a diffraction pattern corresponding to the lithographic pattern, where the diffraction pattern indicates a plurality of spatial frequency components corresponding to the lithographic pattern; determining which of the spatial frequency components need to be captured by a lens in the optical exposure tool in order to accurately reproduce the lithographic pattern; determining a set of illumination conditions required for the optical exposure tool to capture the spatial frequency components necessary for accurately reproducing the lithographic pattern; and illuminating the high transmission attenuated phase-shift mask with this set of illumination conditions.

Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a mask utilized in the photolithography process may contain a circuit pattern corresponding to an individual layer of the IC, and this pattern can be imaged onto a target portion (e.g. comprising one or more dies) on a substrate (silicon wafer) that has been coated with a layer of radiation-sensitive material (in general, a single wafer will contain a whole network of adjacent target portions that are successively irradiated via the projection system, one at a time. In one type of lithographic projection apparatus, each target portion is irradiated by exposing the entire mask pattern onto the target portion in one go; such an apparatus is commonly referred to as a wafer stepper. In an alternative apparatus—commonly referred to as a step-and-scan apparatus—each target portion is irradiated by progressively scanning the mask pattern under the projection beam in a given reference direction (the "scanning" direction) while synchronously scanning the substrate table parallel or anti-parallel to this direction; since, in general, the projection system will have a magnification factor M (generally <1), the speed V at which the substrate table is scanned will be a factor M times that at which the mask table is scanned. More information with regard to lithographic devices as here described can be found, for example, in U.S. Pat. No. 6,046,792, which is incorporated herein by reference.
In a manufacturing process using a lithographic projection apparatus, the mask pattern is imaged onto a substrate that is at least partially covered by a layer of radiation-sensitive material (resist). Prior to this imaging step, the substrate may undergo various procedures, such as priming, resist coating and a soft bake. After exposure, the substrate may be subjected to other procedures, such as a post-exposure bake (PEB), development, a hard bake and measurement/inspection of the imaged features. This array of procedures is used as a basis to pattern an individual layer of a device, e.g. an IC. Such a patterned layer may then undergo various processes such as etching, ion-implantation (doping), metallization, oxidation, chemo-mechanical polishing, etc., all intended to finish off an individual layer. If several layers are required, then the whole procedure, or a variant thereof, will have to be repeated for each new layer. Eventually, an array of devices will be present on the substrate (wafer). These devices are then separated from one another by a technique such as dicing or sawing, whence the individual devices can be mounted on a carrier, connected to pins, etc. Further information regarding such processes can be obtained, for example, from the book "Microchip Fabrication: A Practical Guide to Semiconductor Processing", Third Edition, by Peter van Zant, McGraw Hill Publishing Co., 1997, ISBN 0-07-067250-4, incorporated herein by reference.
For the sake of simplicity, the projection system may hereinafter be referred to as the "lens"; however, this term should be broadly interpreted as encompassing various types of projection system, including refractive optics, reflective optics, and catadioptric systems, for example. The radiation system may also include components operating according to any of these design types for directing, shaping or controlling the projection beam of radiation, and such components may also be referred to below, collectively or singularly, as a "lens". Further, the lithographic apparatus may be of a type having two or more substrate tables (and/or two or more mask tables). In such "multiple stage" devices the additional tables may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposures. Twin stage lithographic apparatus are described, for example, in U.S. Pat. No. 5,969,441 and WO 98/40791, incorporated herein by reference.
Of course, one of the goals in integrated circuit fabrication is to faithfully reproduce the original design on the wafer (via the mask). As the demand to image smaller and smaller features in the semiconductor manufacturing process has continued unabated, the limitations of optical lithography that were was once accepted have been exceeded repeatedly.
Several optical extension approaches have been proposed over the years, the most notable being the alternating aperture phase shirt mask (alt-PSM) first published in the early 1980's. Limitations to alt-PSM practical applications, such as the ability to manufacture the reticles, phase conflicts, design restrictions, and reticle topography effects on the propagating electromagnetic field, have prevented this approach from widespread use in manufacturing. Variations of the alternating aperture phase shift reticle, including 60-120-180 degree multi-phase reticles, 90-270 phase reticles, and dual-trench processing, that to some extent correct for these types of problems, have been employed to some degree and have seen limited application in the wafer lithography process. However, in order to make the process viable for manufacturing, a two-reticle, complimentary alt-PSM has been adopted and is currently the most common method for implementing alt-PSM in actual production.
In such a complimentary alt-PSM approach, the critical gate geometries (i.e., the minimum feature size to be printed) are extracted from the design so that they can be imaged separately from the rest of the gate layer patterns. The gate patterns are imaged by using a "dark field" PSM reticle that has a window cut out on either side of each gate, with one of the windows being phase shifted by 180 degrees relative to the other, thereby giving the desired alternating aperture phase shifting across the gate geometry. A second binary reticle, which contains protection blocks in the areas where the gates are patterned, is used to expose the non-critical geometries and the field area that was not exposed during the first exposure. However, using such a two-exposure method comes at the cost of throughput, multiple reticles, first and second exposure overlay errors caused by stepper alignment and reticle placement errors, as well as imaging distortions that occur at the boundaries of the first and second exposures.
Even if such costs associated with the complimentary alt-PSM method in order to gain the resolution enhancement necessary to print sub-wavelength features are acceptable, very little benefit is achieved as far as reducing the minimum pitch that can be resolved. Specifically, it is preferable to use more coherent illumination (σ<=0.30) in order to obtain the highest resolution enhancement that results from the phase difference on either side of the gate pattern. If so, this can induce very strong proximity effects such as very severe corner rounding or fast and steep CD changes from near 1:1 pitch to isolated features. Both pose additional complications to the already difficult design challenges and further limit the practical implementation.
For other types of photomasks, excluding alt-PSM, the minimum gate pitch is limited to the wavelength (λ) of the imaging system divided by the numerical aperture (NA) of the lens or a Kpitch of approximately 0.50. One way to overcome this pitch limitation is to print every other feature in a first exposure, so as to effectively double the pitch, and then with a second exposure print the features in between the features that were exposed with the first exposure. It is also possible to decompose the desired pattern in a more complex manner which results in two or more patterns where the minimum pitch has been increased to a point where it can be resolved, and where the result of imaging the patterns, one on top of the other, is the final desired pattern. This pattern decomposition strategy can be implemented using binary reticles. However, in such a decomposition method, there is no longer any resolution enhancement that comes from phase shifting. Moreover, the decomposition method has the same disadvantages as any other multiple exposure approach including throughput, multiple reticles, exposure overlay accuracy, and boundaries between the exposures.
Thus, current optical technology techniques continue to be limited in the smallest pitch that can be printed using a particular wavelength. This pitch, which is referred to as kpitch, is defined as:kpitch=(pitch/2)*(NA/lambda),where NA is the numerical aperture of the exposure system and lambda is the exposure wavelength. Indeed, current methods of optical lithography are limited to a kpitch of approximately 0.50.
As such, there is need for a photolithography method which allows for an improvement of the pitch resolution capabilities (i.e., a reduction in kpitch) of currently available photolithography apparatus, and that overcomes the drawbacks associated with currently known techniques.

Method for improved lithographic patterning utilizing multiple coherency optimized exposures and high transmission attenuated PSM


Protocols that provide more efficient operation in dynamic and heterogeneous networking environments are defined. The protocols present a range of levels of error control and sequence order control. Traffic in a link between neighboring network devices is segregated into flows. Each flow is managed in accordance with a selected protocol. It is possible to simultaneously employ different protocols for respective flows within the link.

Not Applicable
Not Applicable
The present invention is related to communication protocols in computer networks, and particularly to reliability protocols for error control in dynamic and heterogeneous computer networks.
Communications protocols for transmitting a sequence of data units from a first application to a second application via a source device, intermediate network routing devices, and a destination device in a computer network are known. xe2x80x9cReliablexe2x80x9d protocols provide for detection and retransmission of data units that are lost in transit. In an xe2x80x9cend-to-endxe2x80x9d reliable protocol the destination device is responsible for detecting the loss of data units. The order of transmission of the data units is maintained by delaying transmission of data units that are received after the loss of a data unit is detected by the destination device. In particular, the data units are buffered at the destination device until the lost data unit is received by the destination device. The source device retransmits the lost data unit to the destination device after being notified of the loss via a repair request message. In a xe2x80x9chop-by-hopxe2x80x9d reliable protocol the destination device and intermediate network devices are responsible for detecting the loss of data units. As in the end-to-end protocol, the order of transmission of the data units is maintained by delaying transmission of data units that are received after the loss is detected. In particular, the data units are buffered at the device that recognized the loss. The lost data unit may be retransmitted by either the source device or an intermediate repair head device. In a xe2x80x9cdatagramxe2x80x9d protocol, which is not a reliable protocol, lost data units are not retransmitted and the order of transmission of the data units is not necessarily maintained. Each of these known protocols performs well under some circumstances and poorly under other circumstances.
One limitation associated with the sequenced reliable protocol is that data forwarding is held up until the lost packet is successfully received. This can significantly reduce the useful data rate of the flow and increase unnecessary transmissions, particularly in environments with large bandwidth-product delays. This is counterproductive for applications that benefit from reliability but can tolerate out-of-sequence delivery.
One limitation associated with the datagram protocol is that loss of data units is not detected and repaired. Some applications are intolerant to data unit loss. Further, the order of transmission of the data units is not necessarily maintained. Some applications are sensitive to the order in which data units are delivered. Also, the application may need, or benefit from, limited reliability which is still better than the current Internet best-effort service.
In accordance with the present invention, new reliability management protocols are employed to provide more efficient operation in dynamic and heterogeneous networking environments. These protocols present a range of levels of error control and sequence order control.
The new protocols include a reliable protocol, a semireliable protocol and an acknowledgement-based semi-reliable protocol. In the reliable protocol the order of transmission of the data units is not necessarily maintained and lost data units are identified and retransmitted. In the semi-reliable protocol the order of transmission of the data units is not necessarily maintained and limited action is taken to identify and recover lost data units. In the acknowledgement based semi-reliable protocol the receiver device in a link acknowledges receipt of each data unit by sending an acknowledgement message to the transmitter device, and the transmitter device is responsible for detecting the loss of data units.

Adaptive retransmission for error control in computer networks


A mounting assembly to mount the base of a hydraulic motor on a mower deck includes a cast iron mounting plate having stiffening structures around the perimeter and spanning the perimeter, and rubber isolators between the mounting plate and the mower deck.

Grass mowing machines with rotary cutting blades under a mower deck may have a hydraulic motor mounted on the deck. For example, grass mowing machines for large or commercial mowing applications such as parks, golf courses, highway medians and athletic fields may have one or more rotary cutting blades under each deck, and a hydraulic motor mounted on the top surface of each deck. These machines may include several mower decks extending from or linked to a frame propelled by an internal combustion engine or other power source.
A hydraulic motor mounted on a mower deck may be connected through hoses or conduits to a hydraulic pump that circulates pressurized fluid to the motors. The shaft of each hydraulic motor may be connected by pulleys and belts to vertically aligned spindles attached to blades under the deck, or directly to the blade spindle or shaft.
To mount a hydraulic motor on a mower deck, a lower surface or base of the motor may be bolted directly to the deck, or bolted to a plate which is then attached to the mower deck. Typically, mower decks that cover two or more rotary cutting blades use a plate that may be spaced one to three inches over the top surface of the mower deck. The spacing may provide necessary clearance for pulleys and belts that interconnect the motor drive shaft and blade spindles. Additionally, to provide clearance, one or more supports may be attached to the top surface of the mower deck, and may extend several inches above the deck's top surface. The plate may be bolted to the support structures.
Hydraulic motors vibrate during operation. When a hydraulic motor is mounted on a mower deck, the vibration of the motor may excite resonance of the mower deck, producing high noise and sound power levels.
There is a need for a low cost mounting assembly for a hydraulic motor on a mower deck that can reduce the excitation of resonance of the mower deck and high noise levels. There is a need for a mounting assembly that isolates, reduces or attenuates noise caused by vibration of a hydraulic motor on a mower deck of a grass mowing machine.


According to the principles of this invention, a polysilicon layer in a semiconductor device is shaped so that in subsequent processing steps a uniform topology is achieved. In particular, a first layer, typically polysilicon, is overlain by a second layer, typically spin-on glass, which is in turn overlain by a mask layer. An opening is formed in the mask layer and the second layer. An isotropic etchant is applied to the structure after the opening is formed. The etchant is formulated to have a differential etch rate in the first and the second layers so that the first layer after etching has an edge surface with a taper of less than 60.degree. and preferably about 45.degree..

1. Field of the Invention
This invention relates generally to a method for forming polysilicon structures in semiconductor devices and more specifically to an improved process for forming tapered polysilicon structures.
2. Description of the Prior Art
Typically, high-capacity dynamic random access memory (DRAM) cell structures are fabricated on a semiconductor chip having many thousands of similar cells and successful operation of the chip requires that all such cells be free of defects. However, the standard process for forming DRAM cells in an array frequently results in an unwanted structure that shorts the transfer gates in two adjacent memory cell structures.
This problem is best understood by considering the fabrication steps used to form prior art DRAM cells on a semiconductor chip. Only the processing steps related to the failure mechanism are described herein. The other processing steps are known to those skilled in the art. As shown in FIG. 1, the substrate is typically overlain by a thin dielectric region 12. For example, dielectric region 12 may consist of a thin silicon oxide layer 12A, typically about 50 .ANG. thick, which is formed on substrate 10, and in turn covered by a silicon nitride layer 12B, typically about 100 .ANG. thick. After formation of silicon nitride layer 12B, polysilicon layer 14 is formed which in turn is overlain by a sacrificial oxide layer 15.
After formation of oxide layer 15, a photoresist mask 17 (FIG. 2) is formed on oxide layer 15 with opening 17-3 that is used to define the extent of the capacitance electrode in the DRAM cell. As oxide layer 15 (FIG. 2) is etched, photoresist mask 17 is undercut as shown in FIG. 3. Photoresist mask 17 is subsequently stripped using a wet etch process leaving the structure illustrated in FIG. 4.
Etched oxide layer 15 is used as a mask for a wet etch of capacitance polysilicon layer 14 to form the structure shown in FIG. 5. Sacrificial oxygen layer 15 is then removed to leave the structure of FIG. 6.
The shape of edge surface 14C of capacitance plate 14 was formed by the wet etch of capacitance polysilicon layer 14 and angle .gamma. between bottom surface 14A of electrode 14 and edge surface 14C is determined by the etching process. Angle .gamma. is typically in the range of about 90.degree. to about 60.degree. with a typical angle being about 80.degree..
The steep inclination of edge surface 14C is one factor that limits the yield of prior art DRAM cells. Oxide layer 16 is subsequently formed on polysilicon layer 14. Oxide layer 16 typically forms a protruding lip 16A as shown in FIG. 7. Lip 16A is the structure which directly contributes to creation of one failure mechanism for a DRAM cell. Lip 16A extends around the perimeter of elliptical opening 28 (FIG. 7).
After formation of oxide layer 16, a triple-etch, using oxide layer 16 as a mask, is used to remove dielectric layers 12A, 12B between oxide layer 16-1, 16-2 so that surface 10.sub.1 of substrate 10 is exposed. Gate oxide 20 is grown on surface 10.sub.1, and then the entire structure is overlain by a polysilicon layer 18A (FIG. 8). A mask and a plasma etch are typically used to form gates 18-1, 18-2 (FIG. 9) from polysilicon layer 18A. However, the plasma etch fails to remove polysilicon 18B under lip 16A because the plasma etch is shielded from this area by lip 16A.
Accordingly, gate structures 18-1, 18-2 are connected by polysilicon 18B (FIG. 10) and the associated DRAM cells are electrically shorted through gate 18.
Hence, the steep inclination of edge surface 14C of capacitance polysilicon results in protruding lip 16A being formed in overlying oxide layer 16 which in turn results in a failure mechanism for the associated DRAM cell. This failure mechanism is a function of the prior art processing steps so that to obtain increased yield, two additional processing steps are required. Removal of polysilicon 18B requires another mask step and an isotropic etch so as to break polysilicon 18B in two places. These additional processing steps while increasing yields also increase processing costs and processing times.

Polysilicon taper process using spin-on glass


A reciprocating piston compressor having at least one cylinder, a reciprocable piston disposed in the cylinder, a crankshaft rotatable in both a forward and a reverse direction, the crankshaft having a cylindrical eccentric portion, a latching member pivotally engaged with the crankshaft, a cam disposed about the crankshaft eccentric portion, the piston operatively connected to the cam, and a spring connected to one of the cam and the crankshaft, the position of the latching member influenced by the spring. The cam is rotatable about the crankshaft eccentric portion between a first cam position corresponding to a first piston stroke length during forward rotation of the crankshaft, and a second cam position corresponding to a second piston stroke length during reverse rotation of the crankshaft. In one of the first and second cam positions, the cam is rotatably locked to the crankshaft eccentric portion by the latching member.

The present invention pertains to reversible reciprocating piston machines, and particularly to reversible reciprocating piston compressors.
Reciprocating piston compressors, such as the compressor disclosed in U.S. Pat. No. 5,281,110, which is assigned to the present assignee, the disclosure of which is incorporated herein by reference, are generally of fixed displacement and powered by an rotating driving source which operates in a single direction. Also known in the art are reversible reciprocating piston compressors in which a piston has a first stroke length when driven by a crankshaft rotating in a first, forward direction, and a second stroke length when driven by the crankshaft rotating in a second, reverse direction, through use of an eccentric cam which rotates relative to the crankshaft between stops thereon corresponding to first and second angular cam positions which, in turn, correspond to the first and second stroke lengths. These reversible compressors provide the advantage of having one displacement when the crankshaft is rotated in the forward direction, and another displacement when the crankshaft is rotated in the reverse direction. Typical variable stroke, reversible drive compressors, however, do not provide means for positively maintaining the cam in the angular position corresponding to the greater stroke length during rotation of the crankshaft. If the cam is not continually maintained in this angular position during crankshaft rotation, the reexpansion of gas in the cylinder after the piston reaches top-dead-center (TDC) may force the piston away from its TDC position at such a speed that the cam may rotate relative to the crankshaft, separating the cam and crankshaft stops. The separation of these stops result in their subsequently slamming together as the rotating crankshaft catches up to the cam, causing considerable component stresses, adversely affecting durability, and producing undesirable noise.
U.S. patent application Ser. No. 09/099,013, filed Jun. 17, 1998, now U.S. Pat. No. 5,951,261, which is also assigned to the present assignee, the disclosure of which is also incorporated herein by reference, provides a means of preventing separation of the cam and crankshaft stops by locking the cam to the crankshaft in a particular angular position when the crankshaft rotates in one of two directions. According to that disclosure, under the influence of centrifugal force, a latching member comprising a pin is slidably extended from a radial bore provided in the eccentric crankpin into engagement with a mating bore provided in the cam. While locking the crankshaft and cam together, the latching pin is subjected to substantial shear forces which may lead to partial or complete failure of the pin. A more durable means for locking the cam and crankshaft stops together, to prevent their separation upon the reexpansion of gas in the cylinder after the piston reaches TDC is desirable.

Reversible, variable displacement compressor


An antenna assembly is capable of being installed in a structure wherein the structure includes a covering and a substructure and the antenna assembly is configured with thin film materials to have a total thickness such that the antenna assembly can be disposed between the substructure and the covering. The antenna assembly may have a total thickness not greater than about 15 millimeters (mm), and may include at least one of a transmitter antenna, a transceiver antenna, and a receiver antenna. The receiver antenna may be configured as an air core antenna or a non-air core antenna. The receiver antenna may be configured as a non-air core receiver antenna in an internal compartment over or within a base insulating layer. The antenna assembly may be at least partially housed within a housing assembly of thin film materials so that both can be disposed between the substructure and the covering.

1. Field of the Disclosure
The present disclosure relates to antenna assemblies for electronic article surveillance (EAS) or radiofrequency identification (RFID) which are made of thin films and/or thin film materials.
2. Background of Related Art
Electronic article surveillance (EAS) systems project a electromagnetic field into an interrogation zone usually at the exit of a retail store. The electromagnetic field excites a marker that returns a signal to the EAS system which alarms to indicate the presence of an EAS marker within the interrogation zone. EAS markers may be placed on merchandise to prevent unauthorized removal of tagged merchandise from a retail establishment, while EAS system transmitter antennas are used to project the electromagnetic field into the interrogation zone. EAS system receiver antennas are used to detect the returned signal from the EAS marker. EAS system transceiver antennas are constructed to perform both transmit and receive functions. By proper design and configuration of the EAS antennas, the system may provide an electromagnetic field of sufficient intensity to adequately excite the EAS marker and provide adequate receive sensitivity so that the return signal received by the EAS system may be detected above the electromagnetic noise in the retail environment.                Properly designed EAS system antennas provide electromagnetic fields that provide the following characteristics:        cover the entire interrogation zone with sufficient intensity field to excite an EAS marker;        have adequate intensity in all spatial orientations throughout the interrogation zone;        do not extend beyond the interrogation zone at high intensities that would cause tagged merchandise outside the interrogation zone to alarm the system; and        comply with regulatory requirements for electromagnetic field emissions.
In addition, because the interrogation zone is often located in locations where retailers desire to display merchandise for sale, typical EAS antenna systems are either concealed or small and streamlined so that the system installation meets the retailer's aesthetic requirements.
In addition, the system also needs to be designed so that the transmitter(s) and the antenna(s) meet the various regulatory or safety agency requirements.
Traditional EAS systems have relied on antennas that are placed in pedestals positioned on opposite sides of an entrance. The antennas project the magnetic field across the opening. However, there is a practical limit as to how wide of an opening may be covered by an EAS system due to limitations in the size of the antennas and the regulatory or safety limitations on the intensity of the electromagnetic field strength.
As a result, the use of pedestals is often impractical to provide an interrogation zone to cover very large openings such as those at mall entrances or exits due to the challenges in meeting the above listed requirements.
In order to adequately cover a wide area such as a mall entrance or exit, an array of several wire loop antennas may be buried in the concrete under the flooring. Such loop antennas are designed as transceivers and project magnetic fields into the region above the floor to detect the returned signal from the EAS marker. Typically these types of antennas are capable of covering an interrogation zone extending up to about 1.2 meters above the floor. Such an antenna also has the advantage of being modular so that it may be extended to cover various width openings. One such system is marketed by Sensormatic Electronics (Boca Raton, Fla., USA) under the brand name "Floormax".
Typically, this type of design has the following installation characteristics:                The antenna coils are mounted in the floor and require significant excavation of the sub-floor for installation;        After installation the antennas are encased in concrete that is re-poured over and around the antennas making them inaccessible without further excavation.
In installations where no metal is present the antennas may be mounted over the sub-floor without excavation. But, due to the thickness of the antenna coil, when antennas are mounted above the sub-floor, layers of additional concrete must be floated onto the surface of the sub-floor to form a gradual slope to cover the antenna. This gradually sloped region may extend several feet on all sides of the antenna. This concrete work is often expensive and may be impractical in some cases.
U.S. Patent Application Publication No. US 2004/0135690 A1, entitled "WIDE EXIT ELECTRONIC ARTICLE SURVEILLANCE ANTENNA SYSTEM" by Copeland. et. al., published on Jul. 15, 2004, and U.S. Patent Application Publication No. US 2004/0217866 A1, also entitled "WIDE EXIT ELECTRONIC ARTICLE SURVEILLANCE ANTENNA SYSTEM" by Copeland et al., published Nov. 4, 2004, both being incorporated by reference herein in their entirety, describe several different systems to cover wide exits or entrances and use various combinations of the following antenna characteristics:                overhead/ceiling mounted ferrite core transceiver or transmitter antennas;        side/wall mounted ferrite core transceiver or transmitter antennas;        overhead/ceiling mounted wire-loop transceiver or transmitter antennas;        side/wall mounted wire-loop transceiver or transmitter antennas;        perimeter wire-loop transceiver or transmitter antennas that extend around the entire perimeter of the interrogation zone;        side/wall mounted core receiver antennas;        overhead/ceiling mounted core receiver antennas;        floor mounted core receiver antennas designed to be mounted in trenches in the sub-floor;        floor mounted loop receiver antennas also designed to be mounted in small trenches in the sub-floor.
However, systems using receivers in the floor still require cutting trenches in the sub-floor routing of wire-loop or core receiver antennas. This is often undesirable due to the expense and inconvenience to the retailer.
Other efforts have been disclosed using a perimeter wire-loop transceiver or transmitter antenna with added overhead/ceiling mounted or side/wall mounted core receiver antennas to cover the interrogation zone. This solution has been successfully deployed for openings up to 3 meters high and about 5 meters in width. Again, this system also requires cutting trenches in the floor to install wire-loop antenna which is undesirable.
As a result, many known approaches require excavation or trenching of the subfloor to allow installation.


A portable computer includes a host, a display portion and a plurality of functional modules. The display portion is pivotally connected with the host and has an accommodation concave space. Each of the functional modules has the same connecting structure to be engaged within the accommodation concave space. Either one of the functional modules is installed within the accommodation concave space.

1. Field of Invention
The present invention relates to an electronic device. More particularly, the present invention relates to a portable computer.
2. Description of Related Art
Notebook computers, palm-size computers or other portable computers are very popular in recent computer market such that more and more functional modules are added to portable computers. However, the portable computers are supposed to be thin and light while adding more functional modules would unavoidably increase either the portable computer's size or weight. How the portable computer being equipped with more functionalities but not increased in size and weight needs more efforts contributed by the computer suppliers.


Electrical energy produced by an energy harvester is stored on a temporary basis in an interim energy storage module before transferring it to a load. The current fed to the load is controlled so that a voltage limit of, for example, a capacitor in the interim storage module is not reached. By at least partially synchronizing the current consumed with the power produced, the capacity of the interim energy storage can be minimized, while still beneficially reducing fluctuations in the current. Current consumed may be determined by the use of a voltage to current look-up table, so that minimal communication overhead between the load and the power source is needed.

Energy may be harvested from the movement of body joints of humans and other animals by converting mechanical energy derived from such movement to electrical energy. Activities where body joints move repeatedly, such as walking, jogging, and running, for example, present opportunities to harvest energy from moving body joints over an extended period of time. In some energy harvesting devices and methods, a generator driven by joint motion is coupled to an electrical load. Since the instantaneous mechanical power provided by body joints during repetitive or cyclical activities varies markedly over the period of each cycle, the harvested electrical power produced also varies markedly over each cycle. For example, the power produced by an energy harvester may on average be 10 W, but it may vary from zero to 60 W multiple times per stride. During a rapid gait, or a change of gait, and where a person is using two energy harvesters, one on each leg, the combined instantaneous output power may reach 120 W.
Intermediate storage capacitors may be used to store the energy produced by energy harvesters, but if these capacitors become fully charged or reach a predetermined voltage limit, then they can no longer accept any more energy. This results in the harvester ceasing to create energy, which in turn causes a sudden drop in the generator torque felt by the user's body joints (e.g. knees), and this causes discomfort to the user.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.

Method and system for bio-mechanical power management


A fast reaction steering mechanism including a variable ratio gear mechanism connected in series with a speed increasing gear mechanism which is disposed in a steering transmission for transmitting rotation of a steering wheel to a steering gear box, the variable ratio gear mechanism comprising a first gear connected to the steering wheel having an effective radius gradually increasing with an increasing steering angle and a second gear connected to the steering box having an effective radius gradually decreasing with an increasing steering angle, and, with the steering angle at its central position, a smallest-radius portion of the first gear engaging with a largest-radius portion of the second gear, thereby providing a maximum steering angle by a reduced rotation of the steering wheel.

This invention relates to a steering mechanism which requires a reduced amount of steering wheel operation to steer the steered wheels up to their maximum steering angle.
Steering mechanisms commonly used in automobiles require more than one full turn of the steering wheel to achieve steering of the steered wheels up to their maximum steering angle. Such steering wheel operation constitutes a fatigue factor.
Therefore, a fast reaction steering mechanism which enables a large steering angle of the steered wheels by a small operation of the steering wheel has been in demand.
To meet such a requirement, the steering gear ratio can be set at a high value, as used in formula cars. However, if the gear ratio is increased, then, steering response in the vicinity of the central position of the steering wheel becomes oversensitive, and, a high speed corrective steering becomes difficult.
In such a fast reaction steering mechanism, since a large change in angle is produced in the steering wheels from a small change in steering angle of the steering wheel, it is preferable that the steering force be increased as the steering angle increases. In this manner, the steering angle is not abruptly increased even if the mechanism is carelessly operated by a driver who is accustomed to an ordinary steering system.
However, if a fast reaction is to be achieved simply by increasing the steering gear ratio, since the steering force is almost constant with respect to changes in steering angle, it is liable to cause excessively sharp steering, which constitutes a safety problem. If the steering force is set high to prevent such sharp steering, the steering force in the vicinity of the central position of the steering wheel also increases, which tends to increase the driver's fatigue.

Mitsubishi Jidosha Kogyo Kabushiki Kaisha


In one embodiment, the present invention provides a device for producing a fire special effect that is suitable for applications in which the viewers of the simulated flame are able inspect the device from relatively close range and/or from a number of perspectives. For example, the device can be used as a torchiere or wall sconce.

The use of a simulated fire or flame is desirable in many applications. For instance, in many theme park attractions (e.g., volcano, battle scene and disaster scenes), the use of a simulated flame or fire is preferred relative to a real flame or fire for a number of reasons. To elaborate, a real flame or fire must typically be located a substantial distance from the audience to prevent members of the audience from getting burned. Further, with respect to attractions that are located indoors, a real flame or fire produces heat and smoke that typically require additional air conditioning and ventilation. In contrast, several types of simulated flame or fire effects can be located close to an audience and do not typically impose the air conditioning and ventilation requirements of a real flame or fire.
There are many types of devices for producing simulated flames or fire. For example, one type of device blows strips of colored material, such as silk, up into the air and shines an appropriately colored light onto the strips. From a distance, these devices provide a reasonably convincing simulated flame or fire. At the other end of the spectrum are devices that provide a television or video monitor with a signal of a pre-recorded fire or flame. Such devices are impractical in theme park applications that require a flame or fire that extends over a distance that is greater than the typical video monitor or television. Yet a further type of device involves the use of a screen of atomized water and the projection of an image or light on the screen that creates the illusion of a flame or fire.

Apparatus for producing a fire special effect


Method and apparatus for providing force feedback in continuous passive motion systems for use in treating or preventing low back pain. A mechanism adjacent to a static back support is provided to initiate continuous passive motion for the lumbar area in order to produce substantial lordotic motion for the spine. A force measuring apparatus is provided for continuously measuring the force exerted by the mechanism on an individual's lumbar area and a system controls the force exerted by the mechanism in order to build up to and then maintain a predetermined force on the lumbar area of the user. Thereafter, a predetermined time is selected to allow the lordotic position of the spine to be returned to its original state.

This invention pertains to continuous passive motion methods and means, and in particular, to such continuous passive motion methods and means as they are applied in the treatment and/or prevention of back pain and the providing of back comfort,
Back pain is a very widespread malady in the United States. Lower back pain can be caused by disease, injury or congenital defect. There are many different types of relevant therapeutic machines on the market today. There have been a number of patents issued in the continuous passive motion field including the U.S. Pat. No. 4,981,131, issued to the applicant Rowland G. Hazard for a Passive Motion Back Support. This patent shows a pneumatic based apparatus for providing continuous passive motion in treating or preventing back pain. A number of devices provide mechanical apparatus for the same purpose. The key difficulty inherent in these designs and requiring solution in order to optimize the user's comfort is the need for integrated automatic force feedback to control the support devices. Without such feedback, devices cannot accommodate variations in the user's spinal compliance, posture and position while providing the desired spinal mobilization comfortably and safely. What is needed is a method and means that will provide force feedback for mechanical and pneumatic devices that deliver back support and/or continuous passive spinal motion. A type of device related to providing massage is shown by the U.S. Pat. No. 5,083,552 issued to Lipowitz for a device that provides vertical compression for the user very rapidly giving a massage effect. The high and low pressure limits of Lipowitz are continuously cycling in the very fast cycle time of half a second to two seconds in order to provide massage. As opposed to the type of control, which is only adequate for massage, safe and comfortable spinal mobilization through a continuous passive motion support requires a pressure feedback system with operating characteristics which vary between phases of the motion cycles. What is also needed is a device and a method which builds up to a preset force range and then holds the force constant for a minimum of five seconds or more during which time movement may or may not occur.
It is the object of this invention to teach a method of and means for providing force feedback in continuous passive motion systems which avoids the disadvantages and limitations, recited above. Another object of this invention is to provide force feedback for producing spinal motion using a prolongation of certain phases of cycle time in order to have the user remain comfortable and safe.

Method of and means for providing force feedback in continuous passive motion systems


A two roll paper dispenser has roll-supporting mandrels mounted on slide blocks in a cantilevered position. The mandrels are automatically movable from a position wherein the first mandrel is located at a juncture of a first path and a second path and the second mandrel is located above the first mandrel in the first path and wherein the first mandrel can be moved from the juncture along carried thereon to open the juncture when sufficient paper is consumed from its roll. A spring engages the first mandrel slide block biasing the mandrel for movement away from the juncture, and the second mandrel slide block is biased for movement along the second path toward the juncture. The mandrels each have a proximal end attached to one of the mandrel slide blocks and a distal free end for insertion thereon of a roll of paper.

Two roll paper dispensers have been widely used particularly in commercial and industrial buildings, public institutions or the like. An example of such a dispenser is shown in commonly owned U.S. Pat. No. 4,422,585 (Schultz et al.), issued Dec. 27, 1983. The present invention relates to improvements in several respects to the type of toilet paper dispensers shown in said patent.

Spring biased automatic multi roll paper dispenser


In a rotary anode type X-ray tube apparatus, a rotary anode target model X-ray pipe is received in housing. Housing is coupled by cooler device to supply a coolant in the housing. Anode target is fixed to a rotary cylinder, which is rotatably supported by a stationary shaft. The stationary shaft is provided with an inner hollow space for guiding the coolant. The coolant guided in the housing is split into two flowing streams, and one of the streams is introduced into the space for cooling of stationary shaft.

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-012698 filed Jan. 22, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a rotary anode type X-ray tube apparatus, and more particularly to a rotary anode type X-ray tube apparatus having a cooling structure, which can improve a cooling efficiency of a rotary anode type X-ray tube received in a housing.
2. Description of the Related Art
In a rotary anode type X-ray tube apparatus, a rotary anode type X-ray tube is received in a housing, and the rotary anode type X-ray tube comprises a cathode for generating an electron beam, an anode target for emitting X-rays upon irradiation of the electron beam, a rotating mechanism for rotatably supporting the anode target, and a vacuum envelope for enclosing the cathode, the anode target, and the rotating mechanism.
FIG. 1 shows a conventional rotary anode type X-ray tube apparatus. In FIG. 1, numeral 41 denotes a housing, and a rotary anode type X-ray tube is enclosed in the housing 41. A coolant such as insulating oil is filled in a space between the housing and the rotary anode type X-ray tube.
In the rotary anode type X-ray tube 41 shown in FIG. 1, there are enclosed a cathode 44 for generating an electron beam, an anode target 45 for emitting X-rays upon irradiation of the electron beam, a rotating mechanism 46 for rotatably supporting the anode target 45. The rotating mechanism 46 comprises a rotary cylinder 47 to which the anode target 45 is fixed, a stationary shaft 48 for rotatably supporting the rotary cylinder 47, and dynamic pressure type bearings.
In the dynamic pressure type bearings, helical grooves of herringbone patterns are formed on the surface or surfaces of the stationary shaft 48 and/or the rotational structure 47, and a liquid metal lubricant such as gallium or gallium alloy is applied to the helical grooves and a gap space between the stationary shaft 48 and the rotational structure 47. A stator coil 49 for generating a rotating magnetic field is provided outside the vacuum envelope 43 and disposed around the rotary cylinder 47.
A cooler device 50 is located outside of the housing 41 and comprises a heat exchange unit, a pump unit and so on. A coolant outlet path such as an outlet pipe P0 couples the cooler device 50 to the housing 41 to supply a coolant from the cooler device 50 to the housing, and a coolant inlet pipe such as an inlet pipe Pi also couples the housing 41 to the cooler device 50 to return the coolant from the housing 41 to the cooler device 50.
In the apparatus shown in FIG. 1, the insulating oil as the coolant which is heated by the rotary anode type X-ray tube 42 is supplied from the housing 41 to the cooler device 50 via the outlet pipe P0 and the insulating oil which has been cooled in the cooler device 50 is also supplied to housing 41 from the cooler device 50 via the inlet pipe Pi so that the insulating oil is circulated in a circulating path as shown by arrow Y.
In an operating mode, the stator coils 49 applies the rotating magnetic field to the rotary cylinder 47 of the rotating mechanism 46 to rotate the rotary cylinder 47 so that the anode target 45 is rotated. The electron beam generated from the cathode 44 is accelerated by a high voltage between the cathode 44 and the anode target 45 and is impinged on the rotated anode target 45 so that X-rays are emitted from the rotated anode target 45. The X-rays pass through a radiation window W1 provided on the vacuum envelope 43 and a radiation window W2 provided on the housing 41 and are guided outside of the housing 41.
Heat is generated from the anode target 45, stator coils 49, the dynamic pressure type slide bearing between the stationary shaft 48 and the rotary cylinder 47, and so on, and is transmitted to the insulating oil circulated between the cooler device 50 and the housing 41. Thus, the insulating oil absorbing the heat cools the X-ray tube.
The dynamic pressure type bearing has advantages of low noise, low vibrations, and long life due to small rotational friction. However, a shearing force is applied to the liquid metal lubricant in rotation of the rotary cylinder and a shearing energy is transferred to the liquid metal lubricant so that the liquid metal lubricant is heated due to the shearing energy and a temperature of the dynamic pressure type bearing is increased. Thus, a diffusion reaction is prompted between the liquid metal lubricant and a bearing material of the rotary cylinder and the stationary shaft. As a result, it may be impossible to constantly maintain a stable rotation of the rotary cylinder. Accordingly, a method of cooling the bearing is employed in the conventional X-ray apparatus, in which a coolant space is provide in the stationary shaft constituting the rotating structure and the insulating oil is supplied to the coolant space to cool the bearing section of the stationary shaft.
There will be described a conventional rotary anode type X-ray tube apparatus having a stationary shaft of a bearing with reference to FIG. 2, in which a coolant space is formed. In FIG. 2, same numerals denote same parts or members in FIG. 1, and a detailed description thereof will be omitted.
A hollow space 51 for circulating a coolant such as an insulating oil to cool a stationary shaft 48 is formed in the stationary shaft 48 in an axial direction and a pipe 52 is so arranged to extend in the hollow space 51 in the axial direction. The pipe 52 is coupled to the inlet pipe Pi at a bottom end 52A thereof and is extended along the hollow space 51, and a top end 52B of the pipe Pi is closely faced to the inner bottom of the pipe Pi.
In the configuration shown in FIG. 2, the insulating oil passing through the inlet pipe Pi is guided in the pipe 51 and flows in the pipe 51 as shown by arrow Y1. The insulating oil is supplied from the opening of the top end 52B to the flow space and path between the pipe 51 and the stationary shaft 52. Then, the insulating oil flows in the flow path and outlets in the space of the housing 41, as shown in FIG. 2. The inlet pipe Pi, the pipe 51, and the flow path between the pipe 51 and the stationary shaft 52 constitutes a part of the circulating coolant path for guiding the insulating oil, which cools the bearing to maintain the temperature of the bearing in a predetermine temperature range.
Thereafter, the insulating oil flowed from the flow path in the stationary shaft 52 into the space in the housing 41 flows to the stator coils 49 and the vacuum envelope 43 to absorb heat generated from the stator coils 49 and the vacuum envelope 43 and is supplied to the cooler device 50 through the outlet pipe P0.
In the conventional rotary anode type X-ray tube apparatus, the coolant hollow space is provided in the stationary shaft constituting the rotating mechanism to absorb heat generated from the bearing, and so on. In this construction, an inner diameter of the stationary shaft in the coolant hollow space can not be set to be relatively large, because the stationary shaft has a relatively small outer diameter and the stationary shaft must have a sufficient mechanical strength. If the stationary shaft has a small inner diameter to have a sufficient mechanical strength, a pressure loss is produced in the coolant flow space or path in the stationary shaft, and a flow rate of the coolant circulating in the apparatus is lowered and the circulating amount of the coolant is decreased in the apparatus. Thus, a cooling efficiency of cooling the stator coils, the vacuum envelop and so on is lowered due to the lowering of the circulating amount of the coolant.
There is an improved method of increasing a cooling efficiency, in which a pumping ability of pumping the coolant is increased in the cooling device. To increase the pumping ability, it is required to design the device to have a large size. Thus, the cooling device becomes high in cost. Although, if the pumping ability is increased, the cooling efficiency may be set to a high level and a viscosity may be large due to the excessive cooling of the bearing and the liquid metal lubricant, and lowering the temperature of the liquid metal lubricant to an unexpected one. Thus, a rotation torque may become unsuitably large within a range of a rotation rate required for the anode target, thus requiring more power to be supplied to the stator coils.
An object of the present invention is to provide a rotary anode type X-ray tube apparatus which can effectively absorb heat generated from a bearing without lowering an amount of coolant flowing through a housing of the apparatus.
According to the invention, there is provided an X-ray tube apparatus comprising:
an X-ray tube including;
a rotary anode target;
a cathode configured to generate electrons to the anode target to cause the anode target to emit X-rays;
a rotary cylinder coupled to the anode target:
a stationary shaft configured to rotatably support the rotary cylinder, the stationary shaft having an opening and a hollow space communicating with the opening;
a dynamic pressure type bearing provided between the stationary shaft and the rotary cylinder; and
a vacuum envelope configured to receive the anode target, the stationary shaft, the rotary cylinder, and the bearing;
a housing configured to receive the X-ray tube, in which a coolant is filled;
a cooler device configured to cool the coolant and circulate the coolant between the cooler device and the housing:
a coolant splitter configured to split the coolant supplied from the cooler device into coolant streams in the housing, one of the coolant streams being guided in the hollow space of the stationary shaft.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.


A propylene polymer composition stabilized against oxidative degradation comprising. (1) 100 parts by weight of a propylene polymer, PA1 (2) 0.001 to 5 parts by weight of a poly(tertiary-butylated p-vinyl phenol) composed substantially of monomeric units represented by the following formula (I) ##STR1## wherein R.sub.1 represents a hydrogen atom or a tertiary butyl group, and (3) 0.001 to 5 parts by weight of a dialkylthiodipropionate represented by the following formula (II) EQU S--C.sub.2 H.sub.4 COOR).sub.2 (II) PA1 wherein R represents an alkyl group containing 10 to 20 carbon atoms.

1. Field of the Invention
This invention relates to a propylene polymer composition stabilized against oxidative degradation comprising (1) a propylene polymer, (2) a poly(tertiary-butylated p-vinyl phenol) as a stabilizer, and (3) a dialkylthiodipropionate as an auxiliary stabilizer.
2. Description of the Prior Art
Polypropylene is a crystalline polymer having a high molecular weight and a high degree of stereoregularity. Because of its high melting point and high strength, polypropylene has found extensive applications as films fibers, tubings and molded articles.
Polypropylene has a number of hydrogen atoms on tertiary carbon atoms in the polymer chain. The hydrogen atoms on the tertiary carbon atoms are very reactive, and are a cause of oxidative degradation. Furthermore, polypropylene frequently contain catalyst residues containing titanium and aluminum employed at the time of polymerization, and these catalyst residues catalytically accelerate the degradation of polypropylene.
Accordingly, a great need exists for stabilizers capable of inhibiting the degradation of polypropylene. The previous practice has been to employ stabilizers effective for polyethylene to polypropylene. However, since polypropylene is fabricated at far higher temperatures than polyethylene, many stabilizers effective for polyethylene do not always exhibit stabilizing effects on polypropylene. Many of these stabilizers are effective only for short periods of time, or are hardly effective at all. For this reason, the use of polypropylene has been markedly restricted despite the superior properties of polypropylene.
Of the stabilizers heretofore used, phenolic anti-oxidants such as 2,6-di-tert.-butyl-p-cresol and 4,4'-n-butylidene-bis(2-tert.-butyl-5-methylphenol) have relatively great effects, and are used as additives for polypropylene resins. Since, however, the processing temperature for polypropylene resins is high, these compounds volatilize during processing, or are easily extracted from the resins by water, oils, etc. As a result, these compounds are capable of stabilizing the resins only for a short period of time. Attempts have also been made to improve the resistance of these stabilizers to volatilization and extraction by increasing their molecular weight, and a low-molecular-weight condensate between phenol and formaldehyde has been suggested, e.g., as disclosed in Die Makromolekulare Chemie, 152, 105-120 (1972). This condensate, however, has only a low stabilization effect, is not capable of stabilizing synthetic resins over long periods of time, and colors the resins. In particular, polypropylene resins susceptible to oxidative degradation are difficult to stabilize with these compounds.
British Pat. No. 971,753 discloses the addition of a poly(alkylated alkenyl phenol) to rubber as an antioxidant. However, poly(alkylated alkenyl phenols) do not have a great stabilizing effect when they are added alone to rubber or a resin.


It is known that improved coating properties can be obtained by plasma action in vacuum deposition, especially by vaporization. Substantially higher coating rates can be attained in vapor deposition, but, with high plasma densities, they result in excessive scattering of the electron beam and reduce the power density. According to the invention, a plasma source, preferably a hollow cathode are source, is arranged in the immediate vicinity of the substrate. Between the evaporator and the substrate there is a device for generating a magnetic field so that the region of high plasma density is separated from the evaporator and the electron beam by the magnetic field. The boundary field lines of this magnetic field run along an arc curving with respect to the substrate.

The invention relates to an apparatus for the plasma-assisted, high rate electron beam vaporization, preferably for the vapor deposition of coatings of compounds on strip-like and plate-like substrates. Typical fields of application are the vaporizing of plastic films with barrier layers for the packaging industry, with scratch-proof coatings for sun-shielding films or foils or with selectively reflecting coatings for heat-absorbing films or foils. Other uses occur in the coating of metallic strips for decorative purposes and for corrosion protection, as well as in the coating of plastic or glass plates for obtaining scratch-proof or selectively reflecting surfaces. However, better coating characteristics also result from the additional plasma action when vapor depositing metallic coatings on different substrates. In particular it is possible to obtain a higher packing density of the coating and therefore improve mechanical, optical and electrical characteristics.
It is known that as a result of plasma action in vacuum coating improved coating characteristics can be obtained. For example, during sputtering, which naturally takes place under plasma action, in general better coating characteristics can be obtained than when vaporizing. However, the coating rates during sputtering are relatively low and are inadequate for many uses. It is possible to achieve higher rates by using the vaporizing procedure.
It is also known to obtain similar coating characteristics to those obtained with sputtering in the case of plasma-assisted vaporizing. Simultaneously with the vapor-deposited material a plasma or the ions extracted from a plasma are made to act on the substrate. The plasma is produced either by ionizing the vapor zone by means of a separately produced low energy electron beam or by igniting an independent discharge between the vaporizer and the substrate (Schiller, S., Heisig, U., Panzer, S., Elekronenstrahltechnologie, VEB Verlag Technik, Berlin, 1976, p.187ff and p.136ff).
The highest coating rates and therefore the lowest coating costs can be achieved by high rate electron beam vaporization. During the vapor deposition of metals coating rates up to 50 .mu.m/s are obtained, but also when vapor depositing compounds coating rates of a few .mu.m/s can be obtained. In order to obtain at such high rates positive effects with regards to the coating characteristics by means of an additional plasma action, correspondingly high plasma densities are required on the substrate. High plasma densities can e.g. be produced with per se known arc discharges. However, it has not hitherto been possible to simultaneously bring into effect the high vaporizing rates and the high plasma densities on the substrate. The high plasma densities lead to such a pronounced spreading or scattering of the electron beam required for vaporization, that it is not possible to achieve the power densities required for high rate vaporization.
It is also known to allow to burn in the vaporizer crucible a plasma arc discharge in addition to the electron beam (Moil, E., Buhl, R., Pulker, H.K., Bergmann, E., Activated Reactive Ion Plating Surface and Coatings Technology 39/40(1989), pp.475-486). However, this additional vaporizer heating does not lead to the coating rates obtained with purely high rate electron beam vaporization. In addition, this procedure is only suitable for vaporizing conductive metals and not for vaporizing insulating compounds. Moreover, the plasma action preferably takes place in the vicinity of the vaporizer crucible and not in the vicinity of the substrate.

Apparatus for plasma-assisted high rate electron beam vaporization

Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.


Pyridine compounds effective in modulation STAT3 and/or STAT5 activation are provided that are useful in the prevention and treatment of proliferative disease and conditions including cancer, inflammation and proliferative skin disorders.

The Jak/STAT signaling pathway is known to be activated in a number of cancers and inflammatory diseases. When activated through phosphorylation of a single tyrosine residue STAT3 dimerizes, translocates to nucleus, and serves as a transcription factor driving the upregulation of a number of proliferative and pro-survival genes including survivin, VEGF, Bcl-2, and Bcl-xL. These gene products are known to promote the growth and metastasis of over 20 tumor types and are also associated with the promotion of several proliferative skin disorders including psoriasis, T-cell lymphoma, and atopic dermatitis.
Inhibition of STAT3 phosphorylation in tumor bearing animals leads to the induction of apoptotic cell death and in preclinical orthotopic models of several diseases a significant reduction in tumor size. Likewise in inflammatory skin diseases inhibition of STAT3 phosphorylation leads to resolution of plaques, scales, and other associated lesions.
While the development of inhibitors of this pathway is currently desirable, a variety of inhibition (such as small molecule, antisense, iRNA) approaches have been tried with unsatisfactory results.

Inhibitors of proliferation and activation of signal transducer and activator of transcription (STATs)

Board of Regents, The University of Texas System


One aspect of the present invention relates to a process of cogeneration utilizing a compressed gas energy storage system which includes a gas storage area, a compression train for pressurizing a gas to be stored in the gas storage area, and an expansion train for depressurizing high pressure gas released from the gas storage area. The process includes operating the compression train during off-peak electricity utilization periods to produce a compressed gas. The compressed gas is stored in the gas storage area and later released during peak electricity utilization periods through the expansion train to generate electricity. This reduces the compressed gas pressure and temperature. The gas can then be used for refrigeration by contacting it with a material to be chilled with that gas. One aspect of this invention involves generating electricity and effecting refrigeration by depressurization of natural gas from high pipeline transmission pressures to lower distribution pressures. A procedure for energy recovery is also disclosed.

There is significant daily variation in the total amount of power required from a baseload power plant. However, it would be costly and wasteful to provide for peak demands of short duration with more baseload power plant machinery.
In the past, power utilities have addressed the problem of providing additional non-baseload peaking power in an economic manner through the use of simple cycle gas turbines ("SCGTs"). Simple cycle gas turbines are state-of-the-art turbomachinery designed for peaking duty operation. Their main elements are an air compressor, a turbine, and a combustor. To meet consumer demand, SCGTs are coupled to electric generators to provide additional power to baseload power plants during peak loads.
Most recently, power utilities have addressed this problem of supplying peaking power in a cost effective manner by use of Compressed Air Energy Storage ("CAES") systems. CAES plants store off-peak energy from relatively inexpensive energy sources such as coal and nuclear baseload plants by compressing air into storage devices such as underground caverns or reservoirs. Underground storage can be developed in hard rock, bedded salt, salt dome, or aquifer media.
Following off-peak storage, the compressed air is withdrawn from storage, heated with fuel, and expanded through expanders, i.e., turbines, to provide needed peaking or intermediate power. Since inexpensive off-peak energy is used to compress the air, the need for premium fuels, such as natural gas and imported oil, is reduced by as much as about two-thirds compared with conventional gas turbines. Under these circumstances, utilization of non-peak energy for subsequent production of peak energy is clearly desirable, especially since non-peak energy can often be obtained for far less than the cost of obtaining peak energy.
Compressors and turbines in CAES plants are each connected to a synchronous electrical generator/motor device through respective clutches, permitting operation either solely of the compressors or solely of the turbines during appropriate selected time periods.
During off-peak periods (i.e., nights and weekends), the compressor train is driven through its clutch by the generator/motor. In this scheme, the generator/motor functions as a motor, drawing power from a power grid. The compressed air is then cooled and delivered to storage.
During peak/intermediate periods, with the turbine clutch engaged, compressed air is withdrawn from storage and provided to a combustor. In the combustor, the compressed air oxidizes a fuel, and the combustion by-products are charged to a turbine, which generates power by driving the generator/motor. In this scheme, the generator/motor functions as a generator, providing power to a power grid. To improve the CAES heat rate, waste heat from a low pressure turbine exhaust is used to pre-heat high pressure turbine inlet air in a recuperator.
For a more complete discussion of CAES systems, see M. Nakhamkin, et al. "Compressed Air Energy Storage: Plant Integration, Turbomachinery Development," ASME International Gas Turbine Symposium and Exhibition, Beijing, Peoples' Republic of China, 1985 and M. Nakhamkin, et al. "Compressed Air Energy Storage (CAES): Overview, Performance and Cost Data for 25 MW to 220 MW Plants", Joint Power Generation Conference, Toronto, Canada 1984, both of which are hereby incorporated by reference.
Examples of CAES systems are disclosed in U.S. Pat. No. 4,100,745 to Gyarmathy et al., U.S. Pat. No. 4,593,202 to Dickinson, and U.S. Pat. No. 4,872,307 to Nakhamkin. These systems are directed to electrical power storage and generation alone.
In order to maximize the efficiency of a CAES system, it is desirable to preheat gas released from the storage cavern by heat-exchanging contact with that gas after expansion. See U.S. Pat. No. 4,936,098 to Nakhamkin, U.S. Pat. No. 4,150,547 to Hobson, and U.S. Pat. No. 4,523,432 to Frutschi.
Another heat recovery technique involves the use of heat generated during compression to warm gas released from storage.
In U.S. Pat. No. 4,150,547 to Hobson, compressed air entering an air storage cavern first passes through a heat storage cavern to recover and store (in a heat storage medium) heat in the compressed air. When air is released from the storage cavern, it again passes through the heat storage cavern, where it is heated.
In U.S. Pat. No. 4,347,706 to Drost, boiler water used to drive steam turbines for compressing air is heated in the compressor innercoolers and aftercoolers, and excess energy from the boiler is stored in a thermal storage unit. Air released from storage is passed through preheaters prior to expansion where heat is provided by the thermal storage unit.
U.S. Pat. No. 4,523,432 to Frutschi discloses a CAES system where heat is recovered from the compressor innercoolers and is stored in a heat storage device by passing water between the innercooler and that device. Compressed air released from storage passes through an exchanger where it is heated by hot water from the heat storage device.
Despite the continued development of heat recovery systems for CAES systems, the need to improve the thermal efficiency and match the thermal cycle to demand for such systems remains.

Compressed gas energy storage system with cooling capability


A retrofitting kit includes at least one of an adapter bracket and a retainer configured to engage at least one of an existing troffer light fixture and a T-bar of a ceiling system and a door assembly configured to be held in the ceiling system by the at least one of the adapter bracket and the retainer. The door assembly has a housing, the housing including one or more sidewalls, where the one or more sidewalls extend upward to define a cavity, and a plurality of LEDs having primary light axes extending inward into the cavity. The plurality of LEDs are coupled to the one or more sidewalls and positioned to illuminate at least a portion of the housing from behind with a uniform distribution of light when engaged.

The invention relates generally to a system and method for retrofitting an existing troffer style light fixture. Existing troffer light fixtures can be retrofitted to include a more efficient light source, replace components of a damaged troffer style light fixture, and/or otherwise upgrade or replace an existing troffer light fixture.
A troffer light fixture is a generally square or rectangular tray like housing and light source which is installed in a ceiling system. The ceiling system may be a dropped ceiling, ceiling grid and tile system, or other engineered ceiling system. The troffer light fixture includes a housing which includes a top body wall and four side body walls. Mounted to the troffer housing are typically lamp sockets (e.g., for fluorescent lamps), lighting ballast which receives electrical power from wiring within the ceiling, and/or other components. The troffer light fixture may further include a door which attaches to the troffer housing. The door may be or include a lens and typically opens downward from the troffer housing. It is challenging and difficult to develop a system which allows for quick and easy retrofitting of an existing troffer light fixture. It is also challenging and difficult to develop a system which retrofits an existing troffer light fixture and reuses the existing troffer housing. Further, it is challenging and difficult to develop a system which is compatible with a variety of troffer light fixtures.

Periphery-lit troffer light fixture retrofit systems and methods


A power train infinitely variable from substantially 1:1 ratio to a very high ratio, employing a pair of planetary gear assemblies, each including a sun gear, a ring gear and a planetary carrier having at least one planetary gear operatively connecting the associated ring and sun gears, the planetary gear assemblies having different gear ratios, both planetary assemblies having their sun gears rotatable by a driving member, a driven member operatively connected to the planetary carrier of the assembly of higher ratio, the ring gears being constructed for rotation as a unit, and the planetary carrier of the assembly of lower ratio being variably connectible with the driving member, whereby the overall ratio between driving and driven members is variable in dependence upon the relative speed of the driving member and the planetary carrier of the lower ratio assembly.

The invention is directed to a power train for the transmission of power from a driving member to a driven member with a variable ratio, particularly from something approaching infinity : 1 to substantially 1:1.
The invention is especially applicable to power transmissions requiring very high starting torque and/or high starting ratios i.e. very slow starting movement.
In many cases it is desirable to provide infinitely variable speed ratios without the use of belts, variable pitch pullies, etc., and particularly where speed and torque, etc., are to be automatically controlled.


Apparatus and methods for spinal surgery include a retractor with an elongated body extending along a longitudinal axis between a distal end and an opposite proximal end. The retractor defines a passage between the distal and proximal ends and a window opening into the passage adjacent to the distal end. The apparatus also includes a guide member extending laterally from the proximal end of the retractor and the guide member includes a body extending along an arc. The body defines a number of trajectories each intersecting the window of the retractor. The apparatus further includes an instrument removably mounted to the guide member and the instrument is movable along the guide member and securable to the guide member in any one of the number of trajectories so that the instrument can be moved along the selected trajectory through the window.

Bone fixation devices, such as, for example, bone screws, interbody implants, staples, pins, wires and/or clamping mechanisms, can be used in various medical procedures. For example, known bone screws can be used to repair fractured bone tissue by securing adjacent portions of the bone tissue together to stabilize and/or limit the movement of bone tissue. Known interbody implants can be used between adjacent portions of bone tissue to provide support for and to facilitate bone growth between the portions of bone tissue. For example, some known bone screws and interbody implants can be used as a part of a spinal fixation procedure.
In some procedures, for example, a facet screw can be inserted across the facet joint of the spinal column to fix and/or limit the motion of the facet joint. Such known procedures can include, for example, translaminar facet screw fixation, which includes inserting a facet screw from the base of the spinous process on the contralateral side and through the lamina to traverse the facet joint in a plane perpendicular to the joint surfaces. Facet screws can also be inserted using a transfacet approach, which involves inserting a bone screw via a midline incision or an ipsilateral incision. Such known procedures, however, often involve the use of multiple tools and/or multiple steps, and are performed in an open incision in which the facet joint is exposed and tissue retracted sufficiently to allow placement of the screw through the facet.
Thus, a need exists for improved insertion tools, implants, and procedures for insertion and securement of implants at locations within a patient's body that can minimize intrusion into tissue along the approach to and around the implantation location.

Systems and methods for guiding anchors for facet fixation


Removal of concentrated suspended particulate material from the recirculating carry-over water in a nuclear steam generator is provided by establishing a mud drum or reservoir of relatively quiescent water, permitting the concentrated solids contained therein to settle out prior to returning the water for mixing with the feedwater. Baffles in the mud drum intercept the entering carry-over water in a manner such that only a small portion of it is exchanged by the newly entering water so that, for the most part, there is sufficient residence time in a relatively quiescent environment to settle out the solids.

1. Field of the Invention
This invention relates generally to a nuclear steam generator, and more particularly to a mud drum for collecting the concentrated solids from the recirculating carry-over water within the generator.
2. Description of the Prior Art:
It is well known in the art of steam generators to have certain spaces or volumes therein of relatively low velocity fluid flow to give the solids suspended in the fluid an opportunity to settle out in an area where they can be relatively easily collected and eliminated from the generator.
One example of such structure in a shell and tube type vapor or steam generator is shown in U.S. Pat. No. 3,916,844, wherein the feedwater, upon entering the shell, is received in a settling chamber of low liquid velocity. However, this settling chamber intercepts the incoming feedwater which does not have a very high concentration of suspended solids per unit volume (although it also receives returning carry-over water which has a much higher concentration of suspended particles, but which becomes considerably diluted upon mixing with the incoming feedwater within the chamber). Consequently, to be effective, a very large volume of low velocity feedwater is necessary for effective removal of the suspended solids.

Sludge collection system for a nuclear steam generator