A memory controller has separate memory controller agents that process memory transactions in parallel. A memory controller in accordance with the present invention includes a plurality of memory controller agents, which are coupled to each other via a series of busses, an incoming memory transaction dispatch unit, and an outgoing memory dispatch unit. Memory transactions are received from cacheable entities of a computer system at the incoming memory transaction dispatch unit, and are then presented to the plurality of agents. For each incoming transaction, one of the agents will accept the transaction. Each agent is responsible for ensuring coherency and fulfilling memory transactions for a single memory line. If multiple memory read transactions are received for a single memory line, the agents will configure themselves into a linked list to queue up the requests. The coherency information and memory line data associated with each memory line may be cached by each agent, thereby allowing repeated requests to the same memory line to be serviced more quickly. When two or more agents are queued up to fulfill multiple memory read transactions to the same memory line, the agents cooperate by transferring the coherency information and memory line data associated with each memory line from agent to agent, thereby minimizing the need to access main memory. The agents complete memory transactions back to the cacheable entities via the outgoing memory dispatch unit.

The present invention relates to memory controllers in computer systems. More specifically, the present invention relates to a system memory controller having a plurality of memory controller agents, wherein each memory controller agent contains a coherency controller and a memory controller capable of processing memory transactions for a single memory line.
In early computer systems, memory controllers were relatively simple. Typically, a single processor of the computer system would issue a read or write transaction to a memory controller, and the memory controller would complete the transaction to main memory by performing the specified read or write operation. However, as the art of computer design has progressed, memory controllers have become significantly more complex. Processors typically include multiple levels of cache memories, with each cache memory storing a subset of the contents of main memory. Furthermore, many modern computer systems often have multiple processors and I/O units, with each processor and I/O unit have one or more cache memories and requiring access to main memory. A modern memory controller must be able to efficiently handle memory transactions from each processor and I/O unit, while keeping all cache memories coherent and arbitrating between separate memory transactions to the same memory line.
To better understand the challenges facing designers of modern memory controllers, first consider a cache memory. A cache memory is a small, high-speed buffer memory which is used to hold temporarily those portions of the contents of main memory which it is believed will be used in the near future by a processor or I/O unit. The main purpose of a cache memory is to shorten the time necessary to perform memory accesses, either for data or instruction fetches from memory or writes to memory. The information located in a cache memory may be accessed in much less time than information located in main memory. Thus, a processor or I/O unit with a cache memory needs to spend far less time waiting for instructions and operands to be fetched or stored.
A cache memory is made up of many cache lines of one or more words of data. Each cache line has associated with it an address tag that uniquely identifies the memory line of main memory of which the cache line is a copy. Each time the processor or I/O unit makes a memory reference, an address tag comparison is made to see if a copy of the requested data resides in the cache memory. If the desired memory line is not in the cache memory, the memory line is retrieved from main memory, stored in the cache memory as a cache line, and supplied to the processor or I/O unit.
In addition to using a cache memory to retrieve data from main memory, the processor or I/O unit may also write data into the cache memory, thereby delaying (or, in the case of successive writes to the cache memory, even possibly eliminating) the need to write the data to main memory. When the processor or I/O unit desires to write data to memory, the cache memory makes an address tag comparison to see if the memory line into which data is to be written resides in the cache memory. If the memory line exists in the cache memory and is being held as xe2x80x9cexclusivexe2x80x9d or xe2x80x9cprivatexe2x80x9d, the data is written into the cache line in the cache memory that is holding the memory line. In many systems a data xe2x80x9cdirty bitxe2x80x9d for the cache line is then set. The dirty bit indicates that data in the cache line is dirty (i.e., has been modified), and thus before the memory line is deleted from the cache memory the modified data must be written back to main memory. If the memory line into which data is to be written does not exist in the cache memory or is held as xe2x80x9csharedxe2x80x9d, the memory line must be fetched as xe2x80x9cprivatexe2x80x9d or xe2x80x9cexclusivexe2x80x9d into the cache memory, or the data must be written directly into the main memory.
A shared-memory multi-processor (MP) system has a potentially large number of processors and I/O units, with each processor and I/O unit having one or more cache memories. For simplicity, any processor, I/O unit, or other subsystem having one or more cache memories will be referred to herein as a cacheable entity.
When an access to memory is made in such an MP system, it is necessary to take steps to ensure the integrity of data accessed. For example, when a cacheable entity reads data from memory, it is important to determine whether an updated version of the data resides in the cache of another cacheable entity. If an updated version of the data exists, something must be done to ensure that the entity accesses the updated version of the data, and not the stale version currently stored in main memory. A mechanism that ensures that the updated version of the data is utilized in a memory reference is referred to herein as a cache coherency mechanism.
The most common cache coherency mechanism is typically referred to as a snoop mechanism. A snoop mechanism usually requires the cacheable entities to share a bus such that each cacheable entity can xe2x80x9csnoopxe2x80x9d the memory transactions of the other cacheable entities. However, due to electrical reasons and bandwidth concerns, only a limited number of cacheable entities can share a bus in a manner that allows transactions to be snooped. Therefore, when the number of cacheable entities in an MP system is large, snooping can no longer be effectively used for cache coherency.
The most common cache coherency mechanism for systems with a large number of cacheable entities is a directory-based cache coherency mechanism. A directory-based cache coherency mechanism typically includes a directory structure in main memory. Within the directory structure, line state information exists for each memory line within the main memory. The line state information consists of a number of bits associated with each memory line. The bits for each memory line indicate, for that memory line, the state of the memory line, such as xe2x80x9cprivatexe2x80x9d or xe2x80x9csharedxe2x80x9d, the cacheable entities, if any, that are currently holding copies of the memory line , and any other information relevant to that memory line.
When the memory line is held as xe2x80x9cprivatexe2x80x9d in a cache memory of a first cacheable entity, the memory line is not available for use by other cacheable entities until released by the first cacheable entity, and the first cacheable entity is allowed to modify the contents of that memory line. When the memory line is held as xe2x80x9csharedxe2x80x9d in the cache memories of one or more cacheable entities, the memory line is available for use by other cacheable entities as long as the other entities do not want to hold the memory line as xe2x80x9cprivatexe2x80x9d. While the line is held xe2x80x9csharedxe2x80x9d, the contents of the line are not allowed to be modified.
When a cacheable entity desires to access a memory line, a request is sent to the memory controller. The memory controller reads the line state information for the memory line to determine the current state of the requested memory line. If the line state information bits for the requested memory line indicate that the memory line is held as private in a cache of another cacheable entity, the memory line is recalled to the memory controller. Note that if the memory line is xe2x80x9cdirtyxe2x80x9d, the modified contents of the memory line must also be recalled and then provided to the requesting cacheable entity. When the memory line comes back to the memory controller, the memory controller supplies the memory line to the requester, updates the memory line""s line state information and, updates the data for the memory line in main memory if the memory line was dirty.
If the memory line is requested as private and the memory controller reads the line state information and finds the memory line is shared, the memory controller invalidates copies of the memory line in the cache memories of other cacheable entities (as indicated by the line state information) and then supplies the memory line to the requesting cacheable entity. The memory controller also tags the line state information of the memory line as private and updates the line state information to identify the cacheable entity that now owns the memory line as private.
The memory line recall/invalidate operation can take a significant amount of time. Meanwhile, new requests for the same memory line can be received by the memory controller. Retrying these new requests is complicated in large MP systems because of the need to provide fairness and prevent starvation.
One possible mechanism for providing fairness and preventing starvation is to queue new requests for a particular memory line in the form of a linked list. Once the recalled data or the invalidate acknowledgment is received, the memory controller services the requests for that memory line in the linked list in the order the requests were received. Multiple linked lists for currently active memory lines can exist simultaneously in the memory controller. Such a mechanism was described by Sorin lacobovici et al. in U.S. Pat. No. 5,995,967, which is entitled xe2x80x9cForming Linked Lists Using Content Addressable Memoryxe2x80x9d, is assigned to the same assignee as the present application, and is hereby incorporated by reference as if completely set forth herein.
Large MP computer systems often use a relatively loose ordering model when processing read and write transactions to the same memory line. Operations that require a strict ordering model, such as semaphore operations, are generally performed by obtaining private ownership of a memory line and not releasing ownership of the memory line until the operations have been performed upon the memory line contents in the desired order. Another approach is to export an instruction used to access a semaphore, such as a fetch and add instruction, to be executed at a central location, such as a memory controller.
Because the ordering of read and writes at the memory controller is relatively loose, read and write transactions may be processed in any order. As discussed above, requests to gain access to a memory line may be processed in a xe2x80x9cfirst-in first-outxe2x80x9d order to provide fairness and to prevent starvation, though this is not required. Furthermore, write operations should be processed before read operations to ensure that the read operations receive the most up-to-date data. For example, if a processor is continuously to polling a memory location to see if a flag is set, and a write operation setting the flag arrives after read operation reading the flag, it is desirable to provide the results of the write operation to the read operation. Doing so will eliminate the need to issue another read operation to poll the flag.
Similarly, the most recent write operation received for a particular memory line should invalidate any previously received write operations because the most recent write operation presumably has the currently valid copy of the contents of the memory line. Accordingly, read and write operations are preferably processed with the following ordering semantics: read operations for a particular memory line are queued up for processing in the order received, and any write operation to a memory line is processed before all read operations from the memory line, and the last write operation to a memory line invalidates any previously received write operations to the memory line.
While the above ordering semantics may be stated quite simply, they are, in fact, relatively difficult to implement. Consider that a modern memory controller can process transactions for many memory lines simultaneously, and these transactions can all be in various states of completion. One prior art method of providing the above ordering semantics is to compare each incoming read transaction to all pending write transactions. If a read transaction attempts to access the same memory line as a pending write transaction, the read transaction is stalled until the write transaction is complete. While this method provides proper ordering, it is somewhat inefficient because read operations that could be completed in theory are stalled.
Another prior art method also compares each incoming read transaction to all pending write transactions. However, if a read transaction attempts to access the same memory line as a pending write transaction, the read transaction is completed out-of-order by using the memory line contents provided in the write transactions.
Note that prior art approaches tend to view the control of coherency and the scheduling memory transactions as a centralized problem. As MP systems continue to increase in complexity, memory controllers have tended to become unduly complex, thereby lengthening the time and expense required to design, verify, and debug a particular controller design, and thereby lengthening the time-to-market.
The present invention is a memory controller having separate memory controller agents that process memory transactions in parallel. A memory controller in accordance with the present invention includes a plurality of memory controller agents, which are coupled to each other via a series of busses, an incoming memory transaction dispatch unit, and an outgoing memory dispatch unit.
Memory transactions are received from cacheable entities of a computer system at the incoming memory transaction dispatch unit via an interconnection fabric. The incoming transactions are then presented to the plurality of memory controller agents. For each incoming transaction, one of the agents will accept the transaction. Each agent is responsible for ensuring coherency and fulfilling memory transactions for a single memory line, thereby simplifying the design of the agents. If multiple memory read transactions are received for a single memory line, the memory controller agents will configure themselves into a linked list to queue up the requests.
One of the advantages provided by the present invention is that the coherency information and memory line data associated with each memory line may be cached by each agent, thereby allowing repeated requests to the same memory line to be serviced more quickly. When two or more agents are queued up to fulfill multiple memory read transactions to the same memory line, the agents cooperate by transferring the coherency information and memory line data associated with each memory line from agent to agent, thereby minimizing the need to access main memory.
Memory transactions are completed by the outgoing memory transaction completion unit, which receives the outgoing transactions from the agents and relays the transactions back to the cacheable entities via the interconnection fabric.
The present invention provides many advantages over prior art memory controllers. Because each agent caches a memory line, the present invention correctly, transparently, and efficiently handles read-after-write conflicts to the same memory line. In many prior art memory controllers, if a read transaction attempts to access the same memory line as a pending write transaction, the read transaction is stalled until the write transaction has been completed, which is inefficient. Alternatively, other prior art memory controllers maintain special write queue registers and attempt to service the read operation out-of-order, which adds significant complexity to the design of the memory controller.
The present invention also handles multiple read memory transactions to the same memory line in a fair and deterministic order. Several linked lists may be created and advanced simultaneously. By creating linked lists, the agents allow unrelated memory traffic to proceed using free agents while read-after-read conflicts to the same memory line are queued up by linking other agents together.
The memory controller agents of the present invention adapt dynamically in response to ever changing memory traffic patterns. If memory transactions are repeatedly made to the same memory lines, the agents group together to form linked lists to service these transactions, and will cooperate by exchanging cached data to minimize the need to access main memory. This is especially useful if several cacheable entities repeatedly contend for the same memory line, as is common in semaphore operations. On the other hand, if memory transactions are made to many individual memory lines, the agents will operate independently from each other and service the transactions in parallel.
Compared to prior art memory controllers capable of handling comparable volumes of memory traffic, the memory controller of the present invention is significantly easier to design and verify, thereby minimizing development costs and minimizing time to market.

Memory controller having separate agents that process memory transactions in parallel

Hewlett-Packard Development Company, L.P.


Method and apparatus for establishing a fuel cell unit (10) in the form of an extruded monolith having channels (14), of which every second constitutes a fuel channel (14a) and every other second an oxygen channel (14b). The channels (14) are designed in such a manner that the fuel channels (14a) are displaced laterally in relation to the oxygen channels (14b), in such a way that all the fuel channels (14a) protrude a certain distance from the end points of all the oxygen channels 14b) and all the oxygen channels (14b) protrude a certain distance from the end points of all the fuel channels (14a). The distance is less than the length of respective channels. The invention also relates to a fuel cell device that includes several of the fuel cell units (10) that together establish an enhanced system of fuel cell units that lend themselves to compact.

1. Technical Field
The present invention relates to a fuel cell unit in the form of an extruded monolith comprising channels of which every second constitutes a fuel channel and every other second an oxygen channel. The invention also relates to a fuel cell device comprising (including) several such fuel cell units. In particular, the invention is applied in connection with packing of fuel cell units to a larger system of fuel cell units; for example, a fuel cell device to be used as a power source in a vehicle.
2. Background Art
In the pursuit of environmentally enhanced power sources, for example with respect to propulsion systems for vehicles, fuel cells have been the subject to extensive research. There are many types of fuel cells that use different types of fuel for different purposes. The production of electricity, however, is a common feature of substantially all fuel cells.
All fuel cells are constructed in a layer structure comprising a fuel side, an oxygen side, a membrane and two electrically conducting plates in the form of an anode and a cathode. The membrane is an electrical insulator at the same time as it works as an electrolyte that admits ionic conduction between the anode and the cathode, which are placed on each side of the membrane. The fuel side is normally placed at the anode side and the oxygen side is normally placed at the cathode side. For most fuel cells, the anode, the cathode, and the electrodes consist of a porous carbon material that is coated with a catalyst material such as platinum (Pt). The catalyst material catalyses a reduction of the fuel at the anode side by means of a reduction of electrons and catalyses an oxidation of the oxygen at the cathode side by means of a supply of electrons. These two reactions cause an electron migration, that is, an electrical current from the anode side to the cathode side via an electrode connection. The ionized particles from either the anode side or the cathode side diffuses through the membrane and reacts on the opposing side by forming some kind of compound, for example water. If there is hydrogen on the fuel side and the membrane allows ionized hydrogen to diffuse, the process and arrangement may be referred to as "Proton Exchange Membranes" (PEM). If the membrane allows ionized oxygen to diffuse from the cathode side, reference may be made to "Oxide Fuel Cells" (OFC).
In a structure of a type referred to as "Solid Oxide Fuel Cell" (SOFC), a ceramic solid phase membrane (electrolyte) is utilized. A suitable material that is used is "dense yttrium stabilized zirconium dioxide," which is an excellent conductor for negatively charged oxygen ions at high temperatures around 1830 degrees F. (1000 degrees C.). At such a temperature, it is possible to have an inner reforming of carboniferous fuels.
When using a fuel cell, it is necessary to consider a number of parameters such as weight, volume, degree of efficiency, working temperature, material, fuel, exhausts and the like depending upon within which field of usage the fuel cell shall be used.
In order to satisfy the power need of a larger unit such as a vehicle, more fuel cells are needed. A way to solve the problem with the mounting of the many fuel cells is to extrude a fuel cell unit in the form of a monolith with a substantially honeycomb structure comprising (that includes) a number of fuel cells which thus form a larger, more compact fuel cell. In some cases, a single monolith with a honeycomb structure will not be able to be made large enough to supply sufficient electricity to power such a larger device as an automobile or other type of vehicle due to manufacturing reasons. This can mean that a mounting of several fuel cell units in the form of monoliths with a honeycomb structure is therefore made necessary.
It is previously known to extrude an SFOC fuel cell unit in the form of a monolith with a honeycomb structure in a material of yttrium stabilized zirconium dioxide which constitutes a membrane that conducts ions, but is not electrically conductive. The fuel cell unit then consists of square/rectangular channels defined by extruded walls of yttrium stabilized zirconium dioxide which form rows of fuel conduit channels with a square/rectangular cross-section with a pole of a conducting catalyzing material on the inside of the channel, and rows of oxygen conduit channels with a square/rectangular cross-section with a pole of a conducting catalyzing material on the inside of the channel. The rows of channels are placed in such a way that every second row is a fuel conduit channel and every other second row is an oxygen conduit channel. The fuel conduit channels and the oxygen conduit channels are of equal lengths and sizes, why every short side of the monolithic fuel cell unit is covered by a covering plate with a system of channels that is designed to conduct the fuel and the oxygen, respectively, to the correct row, i.e. to the correct channel. The monolithic fuel cell unit may be connected to other similar fuel cell units, thus acquiring a compact system of fuel cell units with desired power, by designing a larger covering plate to cover the short side of the system of monolithic fuel cell units that have been connected and where the covering plate has been equipped with a system of channels which supplies the fuel channels and the oxygen channels with the correct fluid; respectively, the fuel and oxygen.
Even if previously known systems function well, enhancements may be made concerning acquiring a more compact system of fuel cell units (fuel cell device). According to previously known technology, the covering lid that covers the short side of the fuel cell device is designed with specially adapted channels that shall fit the fuel, oxygen and exhaust channels. For the fuel cell device to function properly, high demands are made upon the fitting and tightness between the covering plate with its channels and the shaped rows of channels in the fuel cell units. The manufacture of such a plate may be expensive, and the special demands make the device quite inflexible. Even if separate bottom-plates were used for the separate extruded fuel cell units, an adaptation should be necessary for the connections that are needed between the different bottom plates, if several such fuel cell units are connected to a fuel cell device.
Further disadvantages with previously known technology is that the channels which are formed in the covering plate cause a quite high fall-off pressure, which reduces the degree of efficiency of the system and makes the distribution of air and fuel more difficult.
If a system of fuel cell units shall be commercially practicable, it is required that the system have a small volume in relation to the amount of power that is produced. It is also necessary that the system be simple to manufacture and inexpensive to manufacture.

Fuel cell unit and fuel cell device comprising a number of said fuel cell units


A hydraulic system which includes a pump for supplying hydraulic fluid to a load and receiving hydraulic fluid therefrom wherein the pump is acoustically isolated from the surrounding water medium. The pump and a motor which drives the pump is enclosed in a pressure vessel, the interior of which is supplied with a gas at a certain pressure less than the ambient water pressure. The pressure of the hydraulic fluid in the return line is maintained at a pressure less than the ambient by a reservoir arrangement which includes a piston and rod assembly with the rod being subject to the ambient water medium. A certain pressure within an oil filled compartment of the reservoir is maintained at a fraction of the ambient water medium pressure by making the ratio of the cross sectional area of the piston to the rod equal to that predetermined fraction. This reduced pressure compartment is hydraulically connected to the fluid return line as well as to a gas regulator.

1. Field of the Invention
The invention in general relates to hydraulic fluid supplies, and more particularly to an arrangement used in the underwater environment wherein a pump supplies hydraulic fluid to a load.
2. Description of Related Art
Various underwater vehicles have hydraulically activated mechanisms which require the supply of a hydraulic fluid. The hydraulic fluid is supplied by a motor driven pump which has a supply line and a return line wherein the return line pressure is controlled by the ambient sea pressure and the supply pressure is a fixed differential pressure above the return pressure.
The pump may be carried on the outside of the vehicle or in a free flooded compartment within the vehicle and in order to reduce pump noise radiation to the surrounding water medium, and to protect the pump body and shaft seal from seeing an excessive differential pressure, a double enclosure acoustic isolation arrangement is provided.
In such arrangement, the pump/motor unit is placed within a first pressure vessel filled with hydraulic fluid at the return line pressure and this pressure vessel in turn is enclosed within a second and larger pressure vessel filled with a gas at a nominal pressure of one atmosphere.
Although radiated pump noise is significantly reduced, the arrangement is bulky, heavy and difficult to make and assemble.
The present invention accomplishes radiated pump noise reduction with a single pressure vessel thereby eliminating cost and significant complexity of a dual pressure vessel arrangement.

Underwater hydraulic system for reducing pump noise


There is provided a vacuum pump which suppresses the propagation of vibrations to an external container without the use of a damper. The vacuum pump has an outer cylindrical portion, a rotor portion and a stator portion accommodated within the outer cylindrical portion to define a transferring portion for a gas sucked from an inlet port, a magnetic bearing for supporting the rotor portion with respect to the stator portion, a motor for rotating the rotor portion with respect to the stator portion, and a base for supporting the outer cylindrical portion and the stator portion. A vibration absorbing member is interposed between the stator portion and the base, which has a natural frequency F=(f1+f3)/2xc2x1(f1xe2x88x92f3)/4, provided that f1, f2 and f3 respectively denote a natural frequency of nutation in conical mode, a natural frequency in parallel mode and a natural frequency of procession in the conical mode, when the rotor portion is rotated at a rated speed.

1. Field of the Invention
The present invention relates to a vacuum pump that is communicated with an external container to suck gas contained within the external container, and more particularly, to a vacuum pump that can suppress the propagation of vibrations to the external container without the use of dampers.
2. Description of the Related Art
A vacuum pump, such as a turbo-molecular pump or a thread groove-type pump, is known, which is communicated with an external container to suck gas contained within the external container. The vacuum pump is widely used to conduct a vacuum process in which a processing gas within a chamber is exhausted during dry etching, CVD or the like, with a semiconductor manufacturing apparatus, a liquid crystal manufacturing apparatus or the like. The vacuum pump is also used in a measuring apparatus for an electronic microscope or the like.
The vacuum pump is constructed such that an outer cylindrical portion to be communicated with the external container is fixed at one end thereof to a base so that the gas within the external container is introduced into the interior of the outer cylindrical portion at the one end thereof. In the interior of the outer cylindrical portion, a rotor portion and a stator portion are disposed, which are connected directly to or connected through other components to the base. The outer circumferential surface of one of the rotor portion and the stator portion are confronted with the inner circumferential surface of the other to define a gas transferring section for transferring the gas between the rotor portion and the stator portion.
By the rotation of the rotor portion, the gas within the gas transferring section is transferred, and the gas within the external container is sucked therein.
In case of a turbo-molecular pump, a plurality of spacers are disposed on the stator portion coaxially to the rotor portion, and stator blades are respectively disposed between the adjacent spacers to project toward the rotor portion. Rotor blades are disposed on the rotor portion to respectively project into spacers between the adjacent stator blades. The rotor blades, when rotated, collide against and thus transport the gas molecular.
In case of a thread groove-type pump, a thread groove is formed on one of the confronted circumferential surfaces of the rotor portion and the stator portion. Thus, when the rotor is rotated, the gas is transferred using the gas viscosity.
The vacuum pump described above is applied, for instance, to an electronic microscope or other apparatuses, that are largely affected by minute vibrations.
In a related art, the vacuum pump is formed of material which can easily propagates vibrations therethrough, that is, the rotor portion and the base are formed of aluminum alloy (the logarithmic attenuation ratio thereof with respect to vibrations is about 0.0002), and the outer cylindrical portion and bolts for connecting components together are formed of SUS alloy (the logarithmic attenuation ratio thereof with respect to vibrations is about 0.01). Consequently, the vibrations associated with the rotation of the rotor portion are propagated through the stator portion and the outer cylindrical portion to adversely affect the external apparatus connected thereto.
For this reason, as shown in FIG. 4, a technical solution has been proposed, in which a damper D is interposed between a pipe C of the external container and the outer cylindrical portion 116 of the vacuum pump 100 to prevent vibration caused due to the rotation of the rotor portion or the like from being propagated to the external container connected to the vacuum pump.
As an example of the damper D, a thin, SUS-made cylindrical member whose circumferential surface is bent into a bellows shape, and which is coated with a silicon rubber or the like is used. This damper D is designed such that the natural frequency of the entire damper D system is 20 Hz or less in order to have the excellent damping property. During the use of the vacuum pump 100, the damper D is tightened with a hose band or the like externally mounted to the damper D.
However, the use of the damper D as a solution of avoiding the propagation of the vibrations of the vacuum pump 100 requires an extra space in the axial direction corresponding to the length of the damper D. The space required for mounting the damper D to the vacuum pump 100 is generally about 10 cm in the axial direction. The increased cost corresponding to the damper D is also required.
The mounting and removable of the damper D requires labor and is troublesome. The property of the damper D may be changed depending on the mounting state of the damper D.
Additionally, the bellows-shaped member described above can not be formed of a high-rigidity member or a thick member because the bellows-shaped member is required to exhibit an excellent vibration suppressing effect. For this reason, if the excessive force due to the rotational torque of the rotor portion acts on the member, the member may be broken. It is conceivable to arrange a reinforcing member such as a rotation preventive member in order to eliminate the breakage, but the arrangement of the reinforcing member requires an extra cost and makes the structure of the apparatus complicated. Consequently, the maintenance work such as the mounting and removal becomes troublesome.
Further, the natural frequency of the entire pump is about 10 Hz, which is close to the natural frequency of the precession of the rotor (several Hz) generated in the case where the rotor portion of the vacuum pump is supported by magnetic bearings. Consequently, the rotational shift of the rotor portion is likely to be increased due to an external force such as an earthquake, and in some cases, the protection function is activated to stop the rotor portion.
As described above, the related vacuum pump requires the damper to be mounted to the connecting portion to the external container in order to prevent the propagation of the vibrations to the external container, but the mounting of the damper increases the cost and labor and requires the extra space, resulting in the lowering of handling ability.
Further, the related vacuum pump as described above has a built-in motor, and further a certain type of the vacuum pump uses magnetic bearings as bearings. For this reason, magnetic fluxes caused by magnets of the motor and magnetic bearings may leak externally to adversely affect the connected external container such as a vacuum apparatus.
Furthermore, the related vacuum pump as described above is designed such that the outer cylindrical member to be fixed to the vacuum apparatus is electrically connected to cores of electromagnets of the motor and magnetic bearings. In the case where a switching amplifier is used as a driving amplifier for the electromagnets of each of the motor and magnetic bearings, if the voltage applied to the coil of the electromagnet by the switching amplifier is varied, the current excited in the core of the electromagnet may be transmitted through the outer cylindrical member to the external vacuum apparatus, causing an electric noise to adversely affect the vacuum apparatus.
As described above, the related vacuum pump suffers from the generated vibrations, leakage of magnetic flux, and electric noise, which lowers performance, reliability and service life of the vacuum apparatus connected to the vacuum pump.
As a technical solution for eliminating the leakage of magnetic flux to the apparatus connected to the vacuum pump, a technique is known in which the exterior of the outer cylindrical member is housed by a shielding member formed of high permeability material, such as a silicon steel plate, for shielding the magnets of the motor and magnetic bearing. However, this technical solution has a problem in that the vacuum pump is made large in size due to the provision of the shielding member in order to obtain the sufficient shielding effect. It is conceivable to arrange a shielding member just around the exterior of the motor or magnetic bearing. However, because the density of the leaking magnetic flux in this location is high, the thick shielding member is required to provide the sufficient shielding effect, resulting in the increased size and cost of the vacuum pump.
The present invention has been made in order to solve the problems mentioned above. Accordingly, a first object of the present invention is to provide a vacuum pump which can suppress the propagation of vibrations to an external container connected to the vacuum pump without the use of damper.
In addition to the first object, a second object of the present invention is to provide a vacuum pump which can avoid the external leakage of magnetic flux while suppressing the size increase and cost increase.
In addition to the first object, a third object of the present invention is to provide a vacuum pump which can suppress the transmittance of an electric noise to an external container connected thereto.
To attain the first object, the present invention provides a vacuum pump (a first arrangement) comprising: an outer cylindrical portion to be connected to an external container, the outer cylindrical portion having one end portion provided with an inlet port through which a gas within the external container is sucked; a rotor portion rotatably accommodated within the outer cylindrical portion; a stator portion disposed within the outer cylindrical portion, the stator portion and the rotor portion cooperatively defining a transferring portion for transferring the gas sucked through the inlet port; a magnetic bearing for floatingly supporting the rotor portion; a motor portion for rotatingly driving the rotor portion; a base supporting the outer cylindrical portion and the stator portion at the other end portion of the outer cylindrical member; and a vibration absorbing member, interposed between at least one of the outer cylindrical portion and the stator portion and the base, for displaceably supporting the at least one of the outer cylindrical portion and the stator portion with respect to the base, characterized in that the vibration absorbing member has a natural frequency F meeting the following formula:
F=(f1+f3)/2xc2x1(f1xe2x88x92f3)/4
where f1, f2 and f3 respectively denote a natural frequency of nutation in conical mode, a natural frequency in parallel mode and a natural frequency of procession in the conical mode, when the rotor portion is rotated at a rated speed.
In a vacuum pimp comprising: an outer cylindrical portion to be connected to an external container, the outer cylindrical portion having one end portion provided with an inlet port through which a gas within the external container is sucked; a rotor portion accommodated within the outer cylindrical portion; a stator portion disposed within the outer cylindrical portion to define a gas transferring portion in cooperation with the rotor portion; a magnetic bearing for supporting the rotor portion with respect to the stator portion in thrust and radial directions; a motor portion rotating the rotor portion with respect to the stator portion; and a base supporting the outer cylindrical portion and the stator portion at the other end portion of the outer cylindrical portion, vibrations caused on the motor portion and the magnetic bearing are propagated through the stator portion to the base, and further propagated from the base through the outer cylindrical portion to the external container.
Therefore, if the vibration absorbing member is interposed between the stator portion and the base so that the stator portion is displaceably supported to the base, the vibrations caused on the motor portion and the magnetic bearing are propagated from the stator portion to the base after the vibrations are absorbed and attenuated by the vibration absorbing member. Accordingly, it is possible to suppress the propagation of the vibrations to the external container. Further, if the vibration absorbing member is interposed between the outer cylindrical portion and the base so that the outer cylindrical portion is displaceably supported to the base, the vibrations caused on the motor portion and the magnetic bearing are propagated from the base to the outer cylindrical portion after the vibrations are absorbed and attenuated by the vibration absorbing member. Consequently, it is possible to suppress the propagation of the vibrations to the external container.
In the present invention, by using the vibration absorbing member having the natural frequency F meeting the above-noted relationship with respect to the natural frequencies f1, f2 and f3 of the magnetic bearing, the natural frequency of the vibration absorbing member can be set not to close to the natural frequencies of the vacuum pump and the magnetic bearing. Accordingly, the rotational shift of the rotor portion is difficult to be increased due to the external force such as an earthquake, and the rotor portion can be supported stably with respect to the stator portion.
It is sufficient that the vibration absorbing member is partially disposed between at least one of the outer cylindrical portion and the stator portion, and the base. For example, the vibration absorbing member is located at a central portion of each of the segments obtained by dividing a clearance between the outer cylindrical portion or the stator portion, and the base at equal angular intervals with respect to the axis.
The vacuum pump of the first arrangement can be constructed as a vacuum pump in which the vibration absorbing member includes a silicon gel (a second arrangement).
The silicon gel can reduce the rate of the vibration propagation, especially from the low frequency, one or more orders, and thus it is possible to remarkably suppress the propagation of the vibrations.
Each of the vacuum pumps of the first and second arrangements can be constructed as a vacuum pump, in which the vibration absorbing member is interposed between the stator portion and the base, and displacement restricting means is provided for restricting a range where the stator portion is displaceable with respect to the base (a third arrangement).
In the vacuum pump arranged such that the vibration absorbing member is interposed between the stator portion and the base, the stator portion is displaceably supported with respect to the base. For this reason, the stator is displaced with respect to the base when the external force such as the earthquake occurs. The clearance between the stator portion and the rotor portion is set to be as small as possible for the purpose of transferring the sucked gas without escaping toward the inlet port side. For this reason, if the stator portion is displaced with respect to the base due to the external force, then the stator portion may be contacted with the rotor portion to damage components such as rotor blades.
Therefore, it is preferable to provide the vacuum pump with the displacement restricting means for restricting the range where the stator is displaceable with respect to the base, thereby restricting the displaceable range of the stator when the external force occurs and avoiding the contact between the stator portion and the rotor portion.
In the third arrangement, the vacuum pump can be constructed such that: the stator portion includes a protruded portion protruded substantially parallel to a plane defined by the base; a plurality of restricting holes are arranged circumferetially in the protruded portion; the displacement restricting means includes restricting bolts and restricting members, the restricting bolts being formed of a material higher in rigidity than that of the vibration absorbing member, each of the restricting bolts being loosely inserted into the respective restricting holes with a leading end thereof fixed to the stator portion; and each of the restricting member has a restricting cylinder that is fixed around a shaft of each of the restricting bolts, and that is spaced from an circumferetial surface of each of the restricting holes of the protruded portion, and two disk portions that are extended outwardly from respective end portions of the restricting cylinder and that are disposed opposite from each other with respect to the protruded portion while being spaced from the protruded portion (a fourth arrangement).
To attain the first object, the present invention provides a vacuum pump (a fifth arrangement) comprising: a flange portion to be connected to an external container, the flange portion having an inlet port through which a gas within the external container is sucked; an outer cylindrical portion having one end side connected to or integral with the flange portion; a base connected to the other end side of the outer cylindrical portion, the base, the flange portion and the outer cylindrical portion cooperatively defining a hollow portion communicating with an interior of the external container through the inlet port; a stator portion supported to the base, and accommodated within the hollow portion; a rotor portion accommodated within the hollow portion; a bearing rotatably supporting the rotor portion with respect to the stator portion; a motor portion for rotatingly driving the rotor portion, supported by the bearing, with respect to the stator portion; and vibration absorbing means, including a material having a vibration absorbing property, for reducing propagation of vibration using elastic and/or viscous property, the vibration absorbing means being disposed at at least one of the flange portion, the outer cylindrical portion, the base, the stator portion, and joint portions respectively connecting two members selected from the flange portion, the outer cylindrical portion, the base, and the stator portion.
In the vacuum pump of the fifth arrangement, the vibration absorbing means, including a material having a vibration absorbing property, for reducing propagation of vibration using elastic and/or viscous property, is disposed at at least one of the flange portion, the outer cylindrical portion, the base, the stator portion, and joint portions respectively connecting two members selected from the flange portion, the outer cylindrical portion, the base, and the stator portion.
For this reason, the vibrations caused on the motor and the bearing in the interior of the vacuum pump when the rotor portion is rotated are surely reduced by the vibration absorbing means, and unlikely to be propagated to the flange portion. The vibrations caused on the motor and the bearing are propagated to the external container after being reduced by the vibration absorbing means. Accordingly, it is possible to reduce the propagation of the vibrations to the external container without using a solution in a related art in which a vibration absorbing member, such as a damper, is arranged between the flange portion and the external container.
The vibration absorbing means may be disposed at the flange portion, the outer cylindrical portion, the base and/or the stator portion, and/or may be disposed at the joint portion between the flange portion and the outer cylindrical portion, the joint portion between the outer cylindrical portion and the base, and/or the joint portion between the stator portion and the base. In the case where the vibration absorbing means is disposed at the flange portion, the outer cylindrical portion, the base and/or the stator portion, these members may be partially or entirely formed of a material having the vibration absorbing property, or the material having the vibration absorbing property or a member having the vibration absorbing property may be added to an available flange portion, outer cylindrical portion, base and/or stator portion. In the case where the vibration absorbing means is disposed at the joint portion between the flange portion and the outer cylindrical portion, the joint portion between the outer cylindrical portion and the base, and/or the joint portion between the stator portion and the base, a joint member(s) may be interposed between the flange portion and the outer cylindrical portion, between the outer cylindrical portion and the base, and/or between the stator portion and the base, and the joint member may be partially or entirely formed of the material having the vibration absorbing property, or the material having the vibration absorbing property or the member having the vibration absorbing property may be added to the joint member. The flange portion, the outer cylindrical portion and the vibration absorbing material therebetween may be formed integrally, the outer cylindrical portion, the base and the vibration absorbing material therebetween may be formed integrally, and the stator portion, the base, and the vibration absorbing material therebetween may be formed integrally.
The external container may be a chamber or the like of a semiconductor manufacturing apparatus or a electronic microscope, in which a vacuum is maintained, or may be a pipe connected to a container such as the chamber. The flange portion may have the inlet portion connected to the container such as the chamber to suck the gas directly from the container, or may have the inlet portion connected to the pipe connected to the chamber or the like to suck the gas from the pipe.
The vacuum pump of the fifth arrangement can be constructed such that: the outer cylindrical portion has an outlet port through which the gas within the hollow portion is discharged; and the vibration absorbing means is disposed at at least one of the flange portion, the outer cylindrical portion and the joint portion connecting the outer cylindrical portion and the flange portion (a sixth arrangement).
Each of the vacuum pumps of the fifth and sixth arrangements can be constructed such that: the base has an outlet port through which the gas within the hollow portion is discharged; and the vibration absorbing means is disposed at at least one of the flange portion, the outer cylindrical portion, the base, and joint portions respectively connecting two members selected from the flange portion, the outer cylindrical portion, and the base (a seventh arrangement).
Each of the vacuum pumps of the fifth to seventh arrangements can be constructed such that the vibration absorbing means includes at least one of a spring member, a rubber member formed of a rubber, a gel member formed of a gel material and a bellows (an eighth arrangement).
Each of the vacuum pumps of the sixth to eighth arrangements can be constructed such that: the flange portion is discrete from the outer cylindrical portion; and the vibration absorbing means is disposed at the joint portion connecting the flange portion and the outer cylindrical portion (a ninth arrangement).
In the vacuum pump of the ninth arrangement, the vibrations propagated to the outer cylindrical portion, including the vibrations of the motor and the bearing caused within the vacuum pump when the rotor portion is rotated and the vibrations due to an external factor such as a vibration propagated from a back pump, are all reduced by the vibration absorbing means, and then propagated to the external container. Accordingly, it is possible to remarkably reduce the vibrations on the external container.
The vacuum pump of the ninth arrangement can be constructed as a vacuum pump comprising: an outer cylindrical portion defining a hollow portion accommodating therein a stator portion and a rotor portion rotatable with respect to the stator portion; a cylindrical flange portion discrete from the outer cylindrical portion and having an inlet port for a gas contained within an external container; elastic supporting means, fixed to the outer cylindrical portion, for elastically displaceably supporting the flange portion with respect to the outer cylindrical portion; a communicating member communicating the inlet port of the flange portion with the hollow portion of the outer cylindrical portion; and a motor for rotating the rotor portion with respect to the stator portion to suck the gas contained within the external container from the inlet port of the flange portion through the communicating member to the hollow portion of the outer cylindrical portion. That is, the vacuum pump is provided with the elastic supporting means serving as the vibration absorbing means for reducing the propagation of the vibration from the outer cylindrical portion to the external container. Accordingly, the required space in the axial direction is not increased in comparison to a solution in a related art in which vibration absorbing means such as a damper is disposed between the flange integral with the outer cylindrical portion and the external container. By arranging the elastic supporting means on the outer circumferential surface of the outer cylindrical portion, the space in the axial direction can further be made small.
In the vacuum pump of the ninth arrangement, the vibration absorbing means can also be used as the communicating member communicating the inlet port of the flange portion with the hollow portion of the outer cylindrical portion. In this case, if the vibration absorbing means is directly fixed to the circumferential surface of the outer cylindrical portion, a hermetical sealing state must be established between the outer cylindrical portion and the elastic supporting means. If the vibration absorbing means is fixed with respect to the outer cylindrical portion through an additional member, the hermetical sealing state must be established between the additional member and the outer cylindrical portion and between the additional member and the vibration absorbing means.
In the vacuum pump of the ninth arrangement, the vibration absorbing means may include an elastic member connecting the outer circumference of the outer cylindrical portion to the flange portion, and a bellows juxtaposed to the elastic member to connect the outer circumference of the outer cylindrical portion to the flange portion. In this vacuum pump, if the vacuum pump is activated to reduce the internal pressure in the outer cylindrical portion, the bellows contracts in the axial direction. The bellows also contracts together with the elastic member depending on the displacement of the flange portion with respect to the outer cylindrical portion due to the vibrations and the like. This makes it possible to define a gas passage that extends from the flange portion to the outer cylindrical portion and that is hermetically sealed from the exterior, thereby eliminating the mixture of other members and exterior gas outside the bellows into the vacuum pump. In this case, it is preferable to dispose the elastic member outside the bellows, because molecular contained in the elastic member can be surely prevented from mixing and entering into the vacuum pump by the bellows. It is preferable that a spring constant of the bellows in the axial direction is smaller than that of the elastic member in the axial direction. This makes it possible to prevent the breakage of the bellows even in the case where the pressure within the outer cylindrical portion is increased or decreased or an external impact is applied.
The vacuum pump of the ninth arrangement can have restricting means for restricting a position of the flange portion to a predetermined range with respect to the outer cylindrical portion (a tenth arrangement).
In the vacuum pump of the tenth arrangement, the restricting means restricts the position of the flange portion to the predetermined range with respect to the outer cylindrical portion. Accordingly, even if the large impact such as the breakage of the rotor portion occurs, the elastic member and the bellows are protected from being broken, which, in turn, lowers a possibility of an accident in which the vacuum pump is removed from the external container or the pipe connected to the external container. Thus, the high safety can be ensured.
The present invention achieves the second object by providing the vacuum pump of each of the fifth to tenth arrangements, which further comprises a sheet-like magnetic shielding material that is disposed radially outwardly at the stator portion and the rotor portion to circumscribe the stator portion and the rotor portion, and that is disposed along an inner circumferential surface of the outer cylindrical portion (an eleventh arrangement).
In the vacuum pump of the eleventh arrangement, the magnetic shielding material is disposed outwardly of the stator portion and the rotor portion to avoid the external leakage of the magnetic fluxes caused by electromagnets, permanent magnets and the like. constructing the motor and the magnetic bearing. This magnetic shielding material is disposed outwardly of the stator portion and the rotor portion and separated predetermined distances from the electromagnets and permanent magnets that generate the magnetic fluxes. Accordingly, the magnetic shielding material can effectively eliminate the leakage of the magnetic fluxes with a reduced thickness thereof, and thus the cost of the magnetic shielding material and the installation space therefor can be suppressed. Since the magnetic shielding material is disposed inwardly of the outer cylindrical portion, it is protected by the outer cylindrical portion and less likely to be damaged.
The present invention achieves the third object by providing the vacuum pump of each of the fifth to eleventh arrangements, which further comprises: an insulative portion formed of an electrically high-insulative resistance material, which is disposed at the joint portion connecting the outer cylindrical portion and the flange portion (a twelfth arrangement)


The present invention relates to an antimicrobial wipe effective against Gram positive bacteria, Gram negative bacteria, fungi, yeasts, molds, and viruses comprising a porous or absorbent sheet impregnated with an antimicrobial cleansing composition, wherein the antimicrobial cleansing composition comprises from about 0.001% to about 5.0%, by weight of the antimicrobial cleansing composition, of an antimicrobial active; from about 0.05% to about 10%, by weight of the antimicrobial cleansing composition, of an anionic surfactant; from about 0.1% to about 10%, by weight of the antimicrobial cleansing composition, of a proton donating agent; and from about 3% to about 99.85%, by weight of the antimicrobial cleansing composition, water; wherein the composition is adjusted to a pH of from about 3.0 to about 6.0; wherein the antimicrobial cleansing composition an One-wash Immediate Germ Reduction Index of greater than about 1.3; and wherein the rinse-off antimicrobial cleansing composition has a Mildness Index of greater than 0.3. The present invention also relates to methods for removing germs from the skin using the antimicrobial wipes described herein.

Human health is impacted by many microbial entities. Inoculation by viruses and bacteria cause a wide variety of sicknesses and ailments. Media attention to cases of food poisoning, strep infections, and the like is increasing public awareness of microbial issues.
It is well known that the washing of hard surfaces, food (e.g. fruit or vegetables) and skin, especially the hands, with antimicrobial or non-medicated soap, can remove many viruses and bacteria from the washed surfaces. Removal of the viruses and bacteria is due to the surfactancy of the soap and the mechanical action of the wash procedure. Therefore, it is known and recommended that the people wash frequently to reduce the spread of viruses and bacteria.
Bacteria found on the skin can be divided into two groups: resident and transient bacteria. Resident bacteria are Gram positive bacteria which are established as permanent microcolonies on the surface and outermost layers of the skin and play an important, helpful role in preventing the colonization of other, more harmful bacteria and fungi.
Transient bacteria are bacteria which are not part of the normal resident flora of the skin, but can be deposited when airborne contaminated material lands on the skin or when contaminated material is brought into physical contact with it. Transient bacteria are typically divided into two subclasses: Gram positive and Gram negative. Gram positive bacteria include pathogens such as Staphylococcus aureus, Streptococcus pyogenes and Clostridium botulinum. Gram negative bacteria include pathogens such as Salmonella, Escherichia coli, Klebsiella, Haemophilus. Pseudomonas aeruginosa, Proteus and Shigella dysenteriae. Gram negative bacteria are generally distinguished from Gram positive by an additional protective cell membrane which generally results in the Gram negative bacteria being less susceptible to topical antibacterial actives.
Antimicrobial cleansing products have been marketed in a variety of forms for some time. Forms include deodorant soaps, hard surface cleaners, and surgical disinfectants. These traditional rinse-off antimicrobial products have been formulated to provide bacteria reduction during washing. For example, Dial.RTM. liquid soaps, when used in hand washing, have been found to reduce the amount of the bacteria on the skin by from about 2.0 log (97%) to about 2.5 log (99.7%) in one 30 second handwash, as measured by standard Health Care Personal Handwash Tests (HCPHWT). That is skin washed with these soaps were contaminated with only 0.3%-3% of the number of bacteria compared to before washing. Antimicrobial liquid cleansers are disclosed in U.S. Pat. No. 4,847,072, Bissett et al., issued Jul. 11, 1989, U.S. Pat. No. 4,939,284, Degenhardt, issued Jul. 3, 1990 and U.S. Pat. No. 4,820,698, Degenhardt, issued Apr. 11, 1989, all of which are incorporated herein by reference.
Some of these antimicrobial products, especially the hard surface cleaners and surgical disinfectants, utilize high levels of alcohol and/or harsh surfactants which have been shown to dry out and irritate skin tissues. Dial.RTM. bar soap has been found to provide from 2.5 to 3.0 log reduction in bacteria in one wash, as measured by the HCPHWT. However, Dial.RTM. can be drying to the skin with repeated use. Hibiclens.RTM. Surgical Scrub provides 2.5 to 3.0 log reduction in germs in one wash, however it utilizes a potent cationic antibacterial agent, chlorohexidine, which has product safety concerns. Ideal personal cleansers should gently cleanse the skin, cause little or no irritation, and not leave the skin overly dry after frequent use and preferably should provide a moisturizing benefit to the skin.
Finally, these traditional antimicrobial compositions have been developed for use in a washing process with water. This limits their use to locations with available water.
Cleansing wipes have been used, in the past, to wash hands and face while traveling or in public or anytime water is not available. In fact, consumers have used absorbent sheets impregnated with topical compositions for a variety of purposes. U.S. Pat. No. 4,045,364, Richter, et al., issued Aug. 30, 1977 teaches a dry disposable paper impregnated with a germicidal composition comprising an anionic surfactant, an elemental iodine or iodophor active ingredient and a weak acid for pH adjustment. The compositions utilize iodine actives which are not stable in the presence of substantial amounts of water and insufficient acid levels to provide the improved immediate germ reduction of the present invention. European Patent Application, EP 0 619 074, Touchet et al., published Oct. 12, 1994, teaches the use of sorbic or benzoic acids as antimicrobial agents in a wipe, however does not teach the anionic surfactant and separate antimicrobial active necessary to achieve the residual effectiveness of the present invention. U.S. Pat. No. 4,975,217, Brown-Skrobot et al., issued Dec. 4, 1990 teaches the use of anionic surfactants and organic acids on a wipe, however does not teach the use of the active required to provide the improved residual effectiveness benefits.
Currently marketed Nice'n Clean.RTM., Wash'n Dry.RTM. and No More Germies.RTM. are all antibacterial wipes which utilize harsh cationic surfactants with no additional antibacterial active. These products do not provide the improved immediate germ reduction and are harsh to the skin. Current wipes have been found to give about 1.0 log reduction of germs in One-wash tests.
PCT application WO 92/18100, Keegan et al., published Oct. 29, 1992 and PCT application WO 95/32705, Fujiwara et al., published Dec. 7, 1995 teach non-wipe liquid skin cleansers comprising mild surfactants, antibacterial agents and acidic compounds to buffer the pH which provide improved germ hostility. However, the use of the acid compounds for only pH adjustment therein, results in compositions which do not deliver the undissociated acid required to provide the improved immediate germ reduction of the present invention. This situation is compounded in Keegan and Fujiwara by the preference of mild surfactants, including nonionic surfactants. Neither Keegan nor Fujiwara teach the use of their compositions in a form which can be used without available water, e.g. a wipe.
Hibiclens.RTM. Surgical Scrub provides 2.5 to 3.0 log reduction in germs in one wash, and U.S. Pat. No. 3,141,821, issued to Compeau Jul. 21, 1964; Irgasan DP 300 (Triclosan) .RTM.) technical literature from Ciba-Giegy, Inc., "Basic Formulation for Hand Disinfection 89/42/01"; Bartzokas, C. A., et al, "Evaluation of the Skin Disinfecting Activity and Cumulative Effect of Chlorhexidine and Triclosan Handwash Preparations on Hands Artificially Contaminated with Serratia marcescens", Infection Control, 1987/Vol. 8, No. 4; all set forth antibacterial skin cleansers compositions which could provide improved immediate germ reduction using certain anionic surfactants, antimicrobial actives and acids. However, the selection, therein, of highly active surfactants or cationic actives with safety issues (i.e. chlorohexidine gluconate) results in personal cleansing compositions which are drying and harsh, or potentially unsafe to use.
Given the health impacts of bacteria like Staphylococcus aureus, Streptococcus pyogenes and Clostridium botulinum, it would be highly desirable to formulate antimicrobial cleansing products which provides improved immediate germ reduction on the skin, which are mild to the skin and which can be used without water. Existing products have been unable to deliver all of these benefits.
Applicants have found that antimicrobial wipes which provide such mildness and a new level of immediate germ reduction can be formulated by using known porous or absorbent sheets which are impregnated with improved antimicrobial cleansing compositions. These improved antimicrobial cleansing compositions contain antibacterial actives in combination with specific organic and/or inorganic acids as proton donating agents, and specific anionic surfactants, all of which are deposited on the skin. The deposited proton donating agent and anionic surfactant enhance the selected active, to provide a new level of hostility to bacteria contacting the skin.

Antimicrobial wipes which provide improved immediate germ reduction


Embodiments of the invention relate to evaluation and storage of data in a computer system configured with a shared pool of resources. A multi-level adaptive compression technique is employed to minimize the cost of data storage based upon the type of data being stored and their access pattern. The costs of data storage include capacity, bandwidth, and compute cycles. Data is transformed local to a client in communication with the shared pool, local to the shared pool, or as a combination with a partial transformation local to the client and a partial transformation local to the shared pool.

This invention relates to processing application data for storage in a shared pool of configurable resources. More specifically, the invention relates to evaluating data, quantifying the costs for storing the evaluated data, and selection of both a storage format and storage location based upon evaluation of the application data.
Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computer resources, e.g. networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services, that can be rapidly provisioned and released with minimal management effort or interaction with a provider of service. One of the characteristics of cloud computing infrastructure is that applications can be launched from a plurality of locations and generate data to be stored in one of a plurality of locations within the infrastructure. Several factors drive the decision to store application data in a specific data center within the infrastructure, including availability, user location, disaster awareness, and available facilities.
A storage system provides access to information that is stored on one or more storage devices connected to the storage system. Access to the information is possible by organizing the storage devices into volumes, which logically organize the information stored on the storage devices. The storage system may be further configured to operate according to a client/server model of information delivery to thereby allow many clients to access data containers stored on the system. Each client may request the services of the storage system by issuing file-based protocol messages to the system over the network. A plurality of storage systems may be interconnected to provide a storage system environment configured to service many clients. Each storage system may be configured to service one or more volumes, wherein each volume stores one or more data containers. The relationship between increase storage demand and commodity storage device capabilities is inversely proportional in that as the load of storage increases on the storage system, network bandwidth, storage capabilities and computer power decrease. Accordingly, there is a need to accommodate the burdens of storage devices while taking advantage of the storage space available in the shared pool of resources.

Method and apparatus for optimizing data storage

International Business Machines Corporation


A system, method, and storage medium provide dynamic, packet-based adaptive forward error correction over a lossy bidirectional data communication medium that couples a transmitting device to a receiving device. The transmitting device repeatedly transmits encoded data packets formed by applying, to unencoded data, a forward error correction (FEC) algorithm having a level N that indicates a number of correctable errors. The receiving device attempts to decode the encoded data packets using the FEC algorithm, requesting retransmission of a packet if there are too many errors to correct. The transmitting device decreases the level N when it does not receive such a request within a given duration. By contrast, the transmitting device increases the level N when it receives a sequence of such requests having a threshold length, each request being received less than the given duration after the previous request.

Systems that communicate data using electromagnetic signals suffer from communication errors due to interference or noise. Interference often is produced by uncontrolled electromagnetic sources, while noise comes in many forms, including the random motion of electrons in the communication medium due to their thermal energy. Regardless the source of the errors, information that is transmitted often is not the same as the information received. Moreover, as the data rate of communications channels increases, they become less reliable due to these errors.
One technique developed to correct these communication errors is forward error correction, or "FEC", also called channel coding. FEC works by having the transmitting device send redundant data, which the receiving device uses to correct errors. When data are sent continuously, for example as a stream of bits, FEC uses a "convolutional code" to determine the redundant data. Convolutional codes generate a parity bit by applying a carefully chosen binary polynomial to a sliding window of bits within a data stream. A recursive encoder adds the parity bit back to the data stream itself, while a non-recursive encoder provides the stream of parity data "out of band." Such data streams may be decoded using the Viterbi algorithm, which is cost effective to implement in hardware due to the serial nature of the data processing.
When the data are sent in discrete groups, such as packets, then a "block code" is used. Block codes convert input messages having a fixed length (commonly called "k") into code words having a longer length ("n"). The code words are carefully chosen so that when compared pairwise, they differ in at least a minimum number of positions; this number is the distance ("d"). Such codes can detect (d−1) errors, and can correct up to (d−1)/2 errors, rounded down. Well known block codes include Reed-Solomon codes, Golay codes, BCH codes, Hamming codes, and low-density parity-check (LDPC) codes.
Because redundant data are transmitted, FEC decreases the useful bandwidth of the communication medium. Therefore, there is a need to minimize the amount of redundant data to transmit. However, the amount of error between the transmitting device and the receiving device may change over time, so it is beneficial if the amount of redundant data similarly changes over time. It is known in the art to perform dynamic FEC on a stream of bits using a convolutional or Viterbi encoder and decoder; for example, see U.S. Pat. No. 6,128763 to LoGalbo et al. It is also known in the art to perform static (i.e., "on-or-off") FEC at the block level; for example, see Institute of Electrical and Electronics Engineers (IEEE) Standard for 10 gigabit Ethernet over twisted pair cables, IEEE 802.3an-2006, available at http://standards.ieee.org/about/get/802/802.3.html, which describes the use of an LDPC code. However, there remains a need to perform adaptive FEC at the packet level, rather than the bit level. For example, high performance computing (HPC) systems often send packets over very high speed data interconnects that are particularly susceptible to communication errors.

Packet-based adaptive forward error correction

Hewlett Packard Enterprise Development LP


The cabinet 1 has a base 3 that defines an opening 7, which is sized to receive the tynes of a lifting device, such as a fork lift of the like, for example. This facilitates transportation of the entire cabinet 1. The cabinet 1 has nine drawers 8, each having formations, in the form of a pair of slots 10 and 11, which are adapted for engagement with the tynes. Once the tynes have been inserted, the lifting device operator may then raise the tynes slightly, thereby supporting the drawer 8 on the tynes. The lifting device operator can then remove the drawer 8 that is being supported by the tynes from the cabinet 1.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of this application.
It is known to provide cabinets having a plurality of drawers with a pallet-type base, which enables the entire cabinet to be lifted by the tynes of a lifting device, such as a fork lift, for example. In such cabinets, the individual drawers may be installed and/or removed from the cabinet by hand. However, it has been appreciated by the present inventors that such prior art cabinets are unsuited to some applications in which an individual drawer may be too heavy or cumbersome to be manipulated by hand.


An acoustic filter comprises a piezoelectric layer; an acoustic resonator structure monolithically disposed on the piezoelectric layer, the acoustic resonator structure including an arrangement of planar interdigitated resonator fingers; and a lumped capacitive structure monolithically disposed on the piezoelectric layer and being electrically coupled to the acoustic resonator structure, the lumped capacitive structure including an arrangement of planar interdigitated capacitive fingers, each of at least one of the interdigitated capacitive fingers having an edge that is entirely continuous.

Electrical filters have long been used in the processing of electrical signals. In particular, such electrical filters are used to select desired electrical signal frequencies from an input signal by passing the desired signal frequencies, while blocking or attenuating other undesirable electrical signal frequencies. Filters may be classified in some general categories that include low-pass filters, high-pass filters, band-pass filters, and band-stop filters, indicative of the type of frequencies that are selectively passed by the filter. Further, filters can be classified by type, such as Butterworth, Chebyshev, Inverse Chebyshev, and Elliptic, indicative of the type of bandshape frequency response (frequency cutoff characteristics) the filter provides relative to the ideal frequency response.
The type of filter used often depends upon the intended use. In communications applications, radio frequency (RF) filters are conventionally used in telecommunications systems where information is transmitted over wireless links, for example, in the RF front-ends of base stations, mobile devices, satellite transceivers and ground receivers, Internet of Things (IOT) devices, laptop computers and tablets, fixed point links, and other similar systems, to filter out or block RF signals in all but one or more predefined bands. Of most particular importance is the frequency range from approximately 500-3,500 MHz. In the United States, there are a number of standard bands used for cellular communications. These include Band 2 (˜1800-1900 MHz), Band 4 (˜1700-2100 MHz), Band 5 (˜800-900 MHz), Band 13 (˜700-800 MHz), and Band 17 (˜700-800 MHz); with other bands emerging.
RF filters typically require many design trade-offs to achieve the best compromise for a specific application in such performance parameters as insertion loss, rejection, isolation, power handling, linearity, as well as size and cost. Specific design and manufacturing methods and enhancements can benefit simultaneously one or several of these requirements. Performance enhancements to the RF filters in a telecommunications system can have broad impact to system performance. Improvements realized can come in several ways: cell size, battery life, data rates, network capacity, cost, security, reliability, etc. These improvements can be realized at many levels of the wireless system both separately and in combination, for example, at the RF module, RF transceivers, mobile or fixed sub-system, or network levels.
RF filters are generally built using two circuit building blocks: a plurality of resonators, which store energy very efficiently at a resonant frequency (which may be a fundamental resonant frequency f0 or any one of a variety of higher order resonant frequencies f1-fn); and couplings, which couple electromagnetic energy between the resonators to form multiple reflection zeros providing a broader spectral response. For example, a four-resonator filter may include four reflection zeros. The strength of a given coupling is determined by its reactance (i.e., inductance and/or capacitance). The relative strengths of the couplings determine the filter shape, and the topology of the couplings determines whether the filter performs a band-pass or a band-stop function. The resonant frequency f0 is largely determined by the inductance and capacitance of the respective resonator. For conventional filter designs, the frequency at which the filter is active is determined by the resonant frequencies of the resonators that make up the filter. Each resonator must have very low internal resistance to enable the response of the filter to be sharp and highly selective for the reasons discussed above. This requirement for low resistance tends to drive the size and cost of the resonators for a given technology.
The duplexer, a specialized kind of filter is a key component in the front-end of mobile devices. Modern mobile communications devices transmit and receive at the same time (using LTE, WCDMA or CDMA) and use the same antenna. The duplexer separates the transmit signal, which can be up to 0.5 Watt power, from the receive signal, which can be as low as a pico-Watt. The transmit and receive signals are modulated on carriers at different frequencies allowing the duplexer to select them, even so the duplexer must provide the frequency selection, isolation and low insertion loss in a very small size often only about two millimeters square.
The front-end receive filter preferably takes the form of a sharply defined band-pass filter to eliminate various adverse effects resulting from strong interfering signals at frequencies near the desired received signal frequency. Because of the location of the front-end receiver filter at the antenna input, the insertion loss must be very low so as to not degrade the noise figure. In most filter technologies, achieving a low insertion loss requires a corresponding compromise in filter steepness or selectivity.
In practice, most filters for cell phone handsets are constructed using acoustic resonator technology, such as surface acoustic wave (SAW), bulk acoustic wave (BAW), and film bulk acoustic resonator (FBAR) technologies. The equivalent circuit of an acoustic resonator has two resonances closely spaced in frequency called the "resonance" frequency and the "anti-resonance" frequency (see K. S. Van Dyke, Piezo-Electric Resonator and its Equivalent Network Proc. IRE, Vol. 16, 1928, pp. 742-764). Such acoustic resonator filters have the advantages of low insertion loss (on the order of 1 dB at the center frequency), compact size, and low cost compared to equivalent inductor/capacitor resonators. For this reason, acoustic resonator implementations are often used for RF filtering applications in the front-end receive filter of mobile devices.
Acoustic resonators are typically arranged in a ladder topology (alternating series and shunt resonators) in order to create band pass filters. Acoustic ladder filters have been very successful for handset applications, with more than a billion units currently sold each year. However, the recent trend in wireless technology towards multifunctional devices and a more crowded electromagnetic spectrum requires filters for ever more bands with sharper line shapes, while simultaneously demanding reduction in the size, cost, and power consumption.
In addition to sharpening the line shapes of filter passbands, it is also desirable to ensure that discontinuities in the frequency response reside as far outside of the pass band as possible. For example, a typical acoustic resonator has a plurality of interdigitized fingers (e.g., 80-100 fingers) that reflect acoustic waves back and forth between the fingers. The frequency band over which the acoustic reflections between the fingers add in phase to create the resonance may be referred to as the "Bragg Band." A discontinuity feature in the frequency response occurs at the upper edge of the Bragg Band, i.e., the highest frequency at which the acoustic reflections add in phase. This Bragg resonance can distort the high side of the passband of the bandpass filter, resulting in excessive loss at these frequencies. Thus, because the performance of the filter may be compromised if this discontinuity feature falls within the passband, it is important to ensure that the discontinuity feature falls well outside of the passband of the filter.

Acoustic wave filter with enhanced rejection


The present invention relates to a method for modifying and operating a computer system to perform date operations including the steps of storing at least one subroutine for performing the date operation, modifying the application program to include a call to at least one of the subroutines, the call operative to pass at least one date field representative of at least two dates to the subroutine which has been called, wherein the subroutine determines which of the at least two dates corresponds to the date field according to a predetermined criteria performs a date operation on the date field, and returns a code to the application program for use by the application program in its further operations.

In the year 2000, an interesting problem will face companies whose computer systems utilize dates having a two digit representation for the year. In the current format, the year 2000, 2001, et seq. will be represented by the two digit codes of 00, 01, et seq. Accordingly, these computer systems will be unable to distinguish between the year 2000 and the year 1900, for example, as the latter is also represented by the two digit code 00. Thus, if the computer system was, for example, to compare dates such as 1994 and 2000 to determine which was greater, an erroneous result would occur as the system would interpret the two digit representation of year 2000 (i.e., 00) as being less than the two digit representation of year 1994 (i.e., 94).
One solution to this problem would be to convert all dates within the application system of the computer to use date fields with four digit representations for the year. This, however, is a relatively expensive solution for a variety of reasons. First, this solution requires the creation and testing of programs to convert all date fields in all application files. Second, this solution requires the creation and testing of all modifications to all date field processing routines currently used by the application system. Finally, this solution requires conversion of all files to the new formats together with implementation of all of the modified application processing routines. Other problems with this solution, apart from the cost, include the significant amounts of system outage during the file conversions and the large amount of coordination required to prepare for the conversion while still accommodating normal maintenance activity.
Therefore, it would be advantageous to have a solution to this problem which does not suffer from the problems associated with the above-mentioned solution. It would be advantageous to have a solution which minimizes the coordination efforts necessary to implement the solution. It would be advantageous to have a solution which minimizes the "down time" experienced by the application system. Finally, it would be advantageous to have a solution which could be implemented in a piecemeal manner as part of the normal program maintenance activity.

System and method for modifying and operating a computer system to perform date operations on date fields spanning centuries


A tower-like pressure vessel utilizes the injection of gas bubbles for aeration of liquids. A cylindrical conduit extends vertically in the interior of the vessel. The interior conduit has a first end connected to an inlet liquid flow conduit and a second end disposed immediately adjacent the top of the pressure vessel thereby forming a gap which serves as a flow restriction. An outlet for the vessel is located adjacent to the bottom of the vessel.. A gas injector located outside the pressure vessel injects gas into the inlet liquid flow conduit thereby forming a plurality of small gas bubbles that adhere to the walls of a portion of the inlet conduit having a bend. The small bubbles amalgamate to form larger bubbles substantially consistent in size prior to being swept by the liquid stream through the flow restriction at the top of the vessel. The gas bubbles pass more quickly through the restriction creating a pneumatic acceleration and hammering effect upon the top of a pressure vessel which serves as an impaction target. The liquid then cascades by force of gravity through the gas in the pressure vessel to further impact upon liquid accumulated in the pressure vessel.

Aeration of liquids is required in numerous industrial processes. For example, water treatment systems use oxygenation to remove iron, manganese and gases from water. Oxidization chemically transforms iron into ferric oxide (FeO), and triggers a further reaction with water to form the precipitate ferric hydroxide 2Fe(OH)3. Additionally, oxidization of manganese forms manganese dioxide (MnO2), a catalyst used to oxidize iron and manganese into their respective oxides. These precipitates are then captured in a filter medium and removed from the water. The efficiency of water treatment systems are, therefore, dependent upon the amount of oxygen which the water is capable of absorbing.
Traditionally, four approaches have been employed to increase the absorption capacity of a liquid. One approach is known as the "gravity" method. Under this method droplets of liquid are allowed to fall through air. Another approach is "mechanical" aeration. With this method gas is introduced and the liquid is violently agitated. A different approach is the "spray" method. According to this method liquid is forced through a nozzle and sprayed through the air. Finally, a "diffuser" approach can be employed.
While all of the foregoing methods attempt to decrease the interfacial films between the liquid and gas molecules, the level of aeration achieved is inefficient. Thus a need has arisen for a method of aeration in which a greater efficiency of aeration is achieved.


The present invention relates to an acrylic artificial marble having a granite pattern and a method of manufacturing the same, which can provide a natural marble effect by mixing and molding two or more compounds having different colors and thus can obtain a granite pattern in which patterns of the two or more compounds are smoothly mixed, and which can obtain a desired pattern remarkably similar to a pattern of natural stone by using a multicolor chip sheet.

Generally, because artificial marble formed of an acrylic resin has many advantages such as beautiful appearance, excellent workability, light and excellent strength, it is widely used as a material for counter table and various interior materials. However, there is a technical limitation to provide various patterns using the combination of single-colored chips, compared to natural stone or granite.
In manufacturing the acrylic artificial marble, an inorganic filler such as aluminium hydroxide, calcium carbonate and silica, an initiator such as pigment and hardener, and an additive such as releasing agent and dispersing agent are mixed in syrup mixed with polymethyl methacrylate and a monomer such as methyl methacrylate, and then the mixture is molded and cured in a casting mold.
Herein, a raw material such as pigments and chips is used as a means for indicating a color and a shape. A main component of the chip is the same as the artificial marble. The raw material is prepared by the same process as a manufacturing process of the artificial marble after adding a single color pigment and then ground so as to have various colors and particle sizes.
In the prior art, when manufacturing the artificial marble using the chip, multiple single colored chips of which each has a different color are prepared and then added into the base raw material so as to form a natural granite pattern. However, since the pattern and appearance of the artificial marble manufactured with the single colored chips are monotonous and artificial, there is also a technical limitation to realistically reproduce the natural pattern and color.

Acrylic artificial marble having granite pattern and method of manufacturing the same


Described herein are methods and subsystems for use with a timing generator having an output driver at which a timing signal having timing pulses is output. A method includes controlling the timing generator to cause the output driver to output a timing signal having an expected duty cycle, and filtering the timing signal to produce a DC voltage having a magnitude indicative of an actual duty cycle of the timing signal. The method also includes converting the DC voltage to a digital value indicative of the actual duty cycle of the timing signal. The method can also include comparing the digital value to an expected value corresponding to the expected duty cycle, and using results of the comparing to determine an error associated with the timing generator and/or produce a calibration table that can be used to calibrate the timing generator and/or calibrate a measurement made using the timing generator.

Many electronic devices and systems, such as devices and systems that determine distances to an object based on an optical time-of-flight (TOF) measurements, rely on precise timing signals (e.g., having picoseconds of resolution) from timing generators. In order to test the precision and/or accuracy of such timing generators and/or calibrate such timing generators, it would be useful to measure the precision and/or accuracy of timing signals produced by the timing generators. However, the equipment that is typically used to make such measurements is typically relatively large in size compared to the electronic devices and systems, which makes such measurements difficult and expensive and adds complications during calibrations.

Precision measurements and calibrations for timing generators


In a refrigerator having a compressor settled in a room temperature portion and an expander which is connected to the room temperature portion, a piston of the expander is settled in the room temperature portion and pressure variation at a low temperature portion is transferred to the piston through a gas column in a pipe connecting the room temperature portion and the low temperature portion.

The first problem to be solved in this invention is to improve the reliability and minimize the size of the refrigerator by removing a piston or a displacer which is a moving part in a low temperature portion. In the two stage type Gifford-MacMahon (G-M) refrigerator or the Stirling refrigerator, a sliding seal is used at a low temperature. At low temperatures, elastic materials such as rubber are hardened and can not be used. In order to closely contact an outer periphery of the seal with an inner surface of a cylinder, high precision processing are needed and cost very much. Further, since at low temperatures lubrication oil or grease can not be used, the seal has to be replaced frequently due to wear. Therefore, in a refrigerator having an expander (such as a Claude cycle machine), the seal is not provided in a low temperature portion, but the seal is provided in room temperature portion by using a long piston. However, in this case, in order to decrease heat inflow due to heat conduction through the piston and another heat inflow (shattle loss) due to a difference between temperature distributions in the piston and the cylinder during osciIlating mortion of the piston, the length of the piston should be increased. This prohibits minimizing the refrigerator.
As an attempt to remove the displacer or the piston in the low temperature portion, a pulse tube refrigerator has been proposed. This refrigerator dose not have moving parts in a low temperature portion, but there is a problem to be solved such that degradation of performance of a regenerator at low temperatures should be improved to decrease an attained temperature. This is the second problem that this invention intends to solve. The degradation of parformance is caused because heat capacity of the regenerator becomes smaller than that of helium gas. Recently, it has been reported that the G-M refrigerator or the Starling refrigerator reached to temperatures below 4 K by using magnetic materials having large specific heat capacities at low temperatures as regenerator matrixes. However, the degradation of performance of the regenerator at low temperatures can not be solved in the pulse tube refrigerator.

Research Development Corporation of Japan