A novel trailer body design having a plurality of "dummy" splices thereon is provided by the present invention. The dummy splices are used to improve the aesthetics of a trailer body so that a subsequently performed repair of the body is not noticeable. The side walls of the body are formed from upper and lower panels, and a horizontal logistics member connected between the panels to join the panels together along the length of the body. The horizontal logistics member spaces the panels apart and includes a plurality of spaced apertures therethrough. The apertures align with the space so that equipment can be attached to the inside of the body. The dummy splices are vertically affixed to the outer surface of at least one of the panels and spaced apart from each other along the length thereof. Each vertical splice may be a metal or plastic plate or a decal secured to the outer surface of the panel. When a repair is performed on the trailer body due to damage of the side wall, the damaged portion of the panel, along with the adjacent dummy vertical splices, are cut out of the panel. A replacement wall section is inserted into the cutout and affixed to the remainder of the panel by conventional permanent splices. Because of the remaining dummy splices, the body does not look like it has been repaired.

This invention is generally directed to a novel trailer design and a novel design for improving the aesthetics of a trailer body so that when a repair of the trailer body is subsequently performed, the repair is not noticeable. More particularly, the invention contemplates a trailer body having an upper panel and a lower panel, each of which could be a composite panel, which are joined together along the length of the trailer body by a horizontal logistics splice member and further has a plurality of vertical "dummy" splice members provided on at least one of the panels. When a repair to the trailer body is subsequently performed, the repair is not as noticeable because of the dummy splice members remaining on the trailer body.
A side wall currently used for trailer bodies includes a single panel joined to the upper and lower rails of the trailer body. Because of damage to the side wall panel, for example, caused by an accident, repairs must be undertaken. It is not preferred to replace the entire panel because of the cost involved. Instead, only the damaged portion of the panel is cut out and replaced, with the remainder of the panel remaining intact. The replacement section is spliced into the panel by using conventional, permanent splice members to rivet the replacement section to the undamaged portion of the panel. After the replacement section is spliced therein, the trailer is ready for use.
The disadvantage that results from this type of construction is that after the replacement section has been installed, it is very obvious that the trailer body has been repaired. This is aesthetically undesirable as the "patch job" is unattractive.
The present invention provides a novel solution to this disadvantage by providing vertical "dummy" splice members on the outside of the trailer body to visually break up the length of the trailer body. When a repair is needed, the damaged portion of the panel is removed along with the dummy splice members on each side of the damaged portion and a replacement section is riveted to the undamaged portion of the panel by conventional, permanent splice members to repair the damage. Thus, the repair is not noticeable because of the other dummy splice members. Other features and advantages of the present invention will become apparent upon a reading of the following description, taken in connection with the accompanying drawings.

Trailer with horizontal logistics splice and vertical dummy splice members


A particulate screen suitable for use in a wellbore. The particulate screen is expandable and may be at least partially formed of a bistable tubular. Also, a filter media may be combined with the bistable tubular to limit influx of particulates.

Fluids such as oil, natural gas and water are obtained from a subterranean geologic formation (a "reservoir") by drilling a well that penetrates the fluid-bearing formation. Once the well has been drilled to a certain depth the borehole wall must be supported to prevent collapse. Conventional well drilling methods involve the installation of a casing string and cementing between the casing and the borehole to provide support for the borehole structure. After cementing a casing string in place, the drilling to greater depths can commence. After each subsequent casing string is installed, the next drill bit must pass through the inner diameter of the casing. In this manner each change in casing requires a reduction in the borehole diameter. This repeated reduction in the borehole diameter results in a requirement for very large initial borehole diameters to permit a reasonable pipe diameter at the depth where the wellbore penetrates the producing formation. The need for larger boreholes and multiple casing strings results in the use of more time, material and expense than if a uniform size borehole could be drilled from the surface to the producing formation.
Various methods have been developed to stabilize or complete uncased boreholes. U.S. Pat. No. 5,348,095 to Worrall et al. discloses a method involving the radial expansion of a casing string to a configuration with a larger diameter. Very large forces are needed to impart the radial deformation desired in this method. In an effort to decrease the forces needed to expand the casing string, methods that involve expanding a liner with longitudinal slots cut into it have been proposed (U.S. Pat. Nos. 5,366,012 and 5,667,011). These methods involve the radial deformation of the slotted liner into a configuration having an increased diameter by running an expansion mandrel through the slotted liner. Such methods still require significant amounts of force to be applied throughout the entire length of the slotted liner.
In some drilling operations, another problem encountered is the loss of drilling fluids into subterranean zones. The loss of drilling fluids usually leads to increased expenses but also can result in a borehole collapse and a costly "fishing" job to recover the drill string or other tools that were in the well. Various additives, e.g. cottonseed hulls or synthetic fibers, are commonly used within the drilling fluids to help seal off loss circulation zones.
Furthermore, once a well is put in production an influx of sand from the producing formation can lead to undesired fill within the wellbore and can damage valves and other production related equipment. There have been many attempted methods for controlling sand. For example, some wells utilize sand screens to prevent or restrict the inflow of sand and other particulate matter from the formation into the production tubing. The annulus formed between the sand screen and the wellbore wall is packed with a gravel material in a process called a gravel pack.
The present invention is directed to overcoming, or at least reducing the effects of one or more of the problems set forth above, and can be useful in other applications as well.

Expandable sand screen and methods for use


Second digital information serving as copyright protection information can be stably and reliably read without any effect of a defect or pit missing on a disk-shaped recording medium. The second digital information is recorded onto a disk-shaped recording medium by wobbling a pit sequence recorded as a first signal. The second digital information is recorded so that a plurality of bits constituting the second digital information are allocated in a unit period of an identical sync signal contained in the first signal. During playback, the plurality of bits constituting the recorded second digital information are read a plurality of times every unit period of the sync signal, and information of the read bits is then integrated. Thus, information from a large number of wobbled pits across unit periods of a plurality of sync signals can be integrated to determine the bit values.

In typical compact disks (CDs), a region referred to as an IFPI (International Federation of the Phonographic Industry) code is recorded in an area further towards the center than the area in which signals used by a user, such as an audio signal and a TOC (Table Of Contents), are recorded. This code is imprinted with markings of vendors, manufacturing plants, disk numbers, etc., for the purpose of preventing illegal copies called pirated copies.
The recorded markings of vendors, manufacturing plants, disk numbers, etc., are visually recognizable. In playing back a CD or the like, such markings are not readable on a playback apparatus.
That is, the content of such an IFPI code cannot be reflected in operation control of the playback apparatus. Moreover, as described above, since the content can be visually confirmed, the IFPI code has a problem in that the code itself can be copied with ease.
Recordable optical disks onto which a user is able to readily duplicate CDs, DVDs, etc., have also been commercially available. For example, the use of commercially available CD-R disks and apparatuses allows digital information recorded in a CD to be copied exactly by a simple operation. Such copies can be copied with violating copyright, protected under the copyright law, and another problem occurs in that the copyright owner can get no fair reward.
In order to overcome the foregoing problems, in the related art, assuming that information used by a user, such as an audio signal, is set as first information, second information serving as information for copyright protection or the like is superimposed and recorded on the first information.
In the related art, for example, there has been proposed an optical disk in which a plurality of specific pit sequences, each being configured so that a portion of multiple information pits is arranged so that the center line thereof is displaced in the radial direction, are arranged on an information track in units of data blocks of a recording signal at certain intervals in an intermittent manner.
Another example has been proposed, i.e., an optical disk equipped with an illegal copy preventing function, in which, in a portion of a specific radial area of the disk, the information pit sequences are displaced in the radial direction of the track from the center line of the information pit sequence across the track length where a signal variation detectable in a tracking error signal band occurs (see, e.g., Japanese Unexamined Patent Application Publication No. 9-81938).
Furthermore, in the related art, there has been proposed an optical recording carrier in which first information serving as main information and second information relating to control information for playing back the first information are recorded, wherein third information that is different from the first and second information is recorded in association with the second information such that when the first information is played back based on the second information, the third information is not directly contained in the decoded first information (see Japanese Unexamined Patent Application Publication No. 11-66739).
Furthermore, in the related art, there has been proposed a data recording medium in which first data is recorded by repeating pits and lands for a duration equal to an integer multiple of the duration corresponding to a predetermined basic period, wherein second data is recorded by displacing the pits in the direction perpendicular to the track direction from the center of the track and the displacement is within a predetermined amount as long as an off-track situation does not occur (see Japanese Unexamined Patent Application Publication No. 2000-242929).
Furthermore, in the related art, there has been proposed an optical recording medium in which a recording track is formed of continuous lands or grooves and pits are formed on the recording track based on main data, thereby recording the main data, wherein the pits formed on the recording track a predetermined distance apart are displaced by a predetermined amount in the direction orthogonal to the center line of the recording track in the track direction based on additional data, thereby recording the additional data (see Japanese Unexamined Patent Application Publication No. 2002-197671).
In this publication, claim 5 recites that the amount of displacement ranges from 20 nm to 100 nm.
According to the above-noted publications of the related art, second information is recorded by laterally displacing (wobbling) pits. Such information recording by wobbles is only feasible on a mastering apparatus that irradiates light onto a master optical disk. It is therefore impossible to record information recorded by wobbles onto a recordable apparatus such as a CD-R. The wobbled information is recorded onto a master disk, and the presence of the information is checked during playback. Thus, illegal disks copied by a recordable apparatus such as a CD-R can be eliminated.
However, the publications of the related art have a problem in that a sufficient amount of wobbling is required to ensure that information recorded by the wobbles is detected. This is because the signal for detecting the wobbles has a poor signal-to-noise ratio (SNR).
For example, in Japanese Unexamined Patent Application Publication No. 2002-197671 of the related art, the wobble amount ranges from 20 nm to 100 nm, and it is necessary to manufacture a disk with a relatively large amount of wobble. Such large displacement can cause wobbles to be observed and confirmed using an electron microscope or the like. Therefore, a problem occurs in that the content of the wobbles can be analyzed, and the risk of illegal copying increases.
In general, one conceivable technique to overcome a low SNR is to extend the wobbled area, i.e., a pit sequence, and to remove noise using a low-pass filter. However, an actual optical disk playback apparatus is designed so that a tracking servo is used to adjust the position of a light spot to the center of a wobble. If the wobbled area is extended, the amplitude of a wobble detection signal is gradually lowered according to movement of the spot, and the wobble detection signal has substantially no amplitude at the position where the movement of the light spot is completed.
In view of such functionality of the tracking servo, it is not effective to merely extend the wobbled area. This is because a large wobble amplitude is required in the related art.
The present applicant has proposed an improvement, that is, an optical disk onto which main data is recorded according to the length and pitch of pits along a track and sub-data is recorded by displacing the pits in the inner and outer radial directions with respect to the center of the track, wherein the pits are displaced according to a result of computation of the sub-data and a predetermined binary sequence (see Japanese Unexamined Patent Application Publication No. 2000-195049).
In this optical disk, information recorded by wobbles is detected by integral detection using a predetermined binary sequence. In this invention, one bit of copyright protection information is allocated to one frame of a CD for recording. One frame is a disk length equal to 12 mm. A playback signal for such a long period is detected by integration, thus allowing a wobble recorded with a relatively small amplitude to be sufficiently detected.
This publication of the related art can thus greatly reduce the amount of pit wobble. While overcoming the previously described drawbacks with the related art, practical copyright protection is therefore achievable.
For example, if a defect occurs at the beginning of a frame during playback of an optical disk, a clock variation phenomenon (bit slip) can occur.
In the Japenese Patent Publication No. 2000-195049, if a bit slip occurs, as described above, the clock becomes out of phase, and the binary sequence used in recording is not reproduced and correct data decoding is thus impossible. The bit slip is not overcome until the next sync pattern has been played back. Therefore, if a defect occurs at the beginning of a frame and a bit slip occurs, it is impossible to play back the bit of the data, which is troublesome.
In a case where no error correcting code is added to the sub-information, namely, copyright protection information, if a read error of one bit occurs, a serious problem occurs in that the data must be played back from the beginning.

Mastering device, disc manufacturing method, disc-shaped recording medium, disc reproduction device, and disc reproduction method


A method of generating a purchase order includes receiving purchasing data for the item to be purchased in a computerized system and generating the purchase order based on received purchasing data for the item to be purchased, determining whether a sufficient amount of funds is available for the purchase order, submitting the purchase order for a remedial action to obtain the sufficient amount of funds if the sufficient amount of funds is not available, determining a supplier for the item to be purchased from a plurality of potential suppliers using an automated auction system if a sufficient amount of funds is available, and modifying the purchase order to include data from the automated auction regarding the supplier.

The present description relates generally to the field of generating and managing purchase orders. More particularly, the present invention relates to a method of and system for generating purchase orders using an auction process to determine a supplier for a retail product or service.
The retail business can require that certain purchase orders be processed in a very short amount of time, while other purchase orders must be placed in advance of the desired delivery. For example, changes in current trends in the fashion industry may require that inventory be increased on short notice. Additionally, fashion articles may require ordering well in advance of delivery, in some cases six months or more in advance. For certain aspects of the fashion industry, items may be required to be ordered one or more seasons in advance. An advantageous purchase order system must accommodate this variation in lead times of the ordered items without unnecessarily tying up funds.
Further, tracking inventory and budgets for seasonal items can be important to the profitability of a business. For example, identifying a particularly fast selling item and ordering additional quantities to arrive on time and within a prescribed budget may increase the profitability of a retail location. Accordingly, it is important for a business to carefully plan and schedule purchasing orders for retail products and services to ensure on-time procurement or scheduling within budget constraints. Optimizing the smooth flow of the procurement process increases an enterprise's efficiency and competitiveness and determines its success.
As part of the procurement process, retail businesses and service providers often seek to obtain preferential buying terms by soliciting bids or quotations from several suppliers (e.g., vendors, manufacturers, wholesalers, etc.) for a particular retail product or service. For example, a retailer in the fashion industry may solicit bids from several competing suppliers of basic fashion articles using an auction in order to select the supplier or vendor. The fashion retailer may then select the supplier whose bid provides the most favorable buying terms (e.g., pricing, delivery conditions, etc.) as the source for certain basic fashion articles. Accordingly, optimization of the smooth flow of the procurement process includes efficiently facilitating the solicitation of bids from several suppliers in order to select the best source of a retail product or service.
In view of the foregoing, it would be beneficial to provide a method of and system for generating a purchase order which uses an auction process in order to determine a supplier and price for a retail product or service.

Method of and system for generating purchase orders using an auction process


A method, article and apparatus for advertising via a mobile device. A communication request is received from the mobile device that includes a screen for displaying an ad. One more ad selection criteria are then determined. Such criteria may include a visibility of the ad on the screen; a target audience determined on the basis of information provided from the mobile device; and attributes of the determined target audience. The ad selection is based on the visibility of the ad and the attributes of the target audience. Commands may then be initiated to cause the selected ad to be displayed on the screen of the mobile device.

1. Field of the Invention
The field of the invention relates to mobile devices, specifically to advertising via mobile devices.
2. Description of the Related Art
Advertisers constantly seek out new advertising venues and means for reaching their target audiences. The Internet and consumer electronics provide access to a large audience and opportunities for new advertising techniques. For example, consumers who maintain their own web-sites have become advertising brokers via their web-sites, even though the web-sites may be otherwise non-commercial in nature. Services such as Google Adsense compensate web-site owners who agree to host advertisements "served up" by the Adsense server. By enrolling in such a service, web-site owners typically agree to link their sites to a server that enables advertisements on the web-site. When a user visits a web-site linked to a service such as Adsense, the user sees advertisements sent from the Adsense server. Other innovative advertising media and techniques are continuously being sought out.

Customizing and distributing advertisments to mobile devices on a communication network

International Business Machines Corporation


A storage device tray has a form factor designed to support a larger storage device, and is configured to secure a small storage device, thereby acting as an adapter between storage device sizes. The storage device tray includes a sliding mechanism configured with pegs that may couple to screw holes in the storage device. The sliding mechanism also exerts a force against the storage device to secure that storage device, and may be locked to further secure that storage device. At least one advantage of this approach is that a storage device can be coupled to a storage device tray without using screws.

Field of the Invention
Embodiments of the present invention relate generally to storage device trays, and, more specifically, to a tool-less storage device adapter tray.
Description of the Related Art
A conventional mass storage device may be a hard disk drive (HDD) or a solid-state drive (SSD). Storage devices such as HDDs and SSDs are typically manufactured with standardized 2.5-inch and 3.5-inch form factors. Such conventional storage devices can be coupled to a computing device via a storage device tray. The storage device is usually mounted to the tray using screws, and the tray is then mounted within the computing device.
Conventional storage device trays are typically designed with a large form factor that is capable of housing 3.5-inch storage devices, and computing devices are generally designed to accept storage device trays having this larger form factor. The larger form factor storage device tray not only provides sufficient space for 3.5-inch storage devices, the design also provides sufficient space to house the smaller 2.5-inch storage devices. A 2.5-inch storage device can be mounted within the larger form factor storage device tray using mounting brackets and four small screws. The mounting brackets can be coupled within the storage device tray and provide a stable mounting point. The screws are inserted through screw holes in the mounting brackets, and then tightened into a sink in the storage device to secure the device within. Thus, a larger form factor storage device tray may act as an adapter between a 2.5-inch storage device and a computing device that accepts storage device trays designed to accommodate 3.5-inch storage devices.
One drawback associated with traditional adapter trays is that, as described above, mounting the 2.5-inch storage device within the tray requires a number of small screws in order to securely fasten the storage device. Mounting the storage device using these small screws is tedious and time-consuming and also prone to error. These issues are compounded with larger server machine implementations where tens or hundreds of 2.5-inch storage devices may be deployed.
As the foregoing illustrates, what is needed in the art is a technique for mounting a storage device having a small form factor within a storage device tray designed with a larger form factor.

This patent is subject to a terminal disclaimer.

Tool-less storage device adaptor tray with slider mechanism


A semiconductor memory device storing data having a unit of N bits (N is an integer) includes M memory elements (M is an integer and larger than N) each divided into a plurality of blocks each having a plurality of memory cells each storing one-bit data, and M internal bus lines each carrying one-bit data and connected to a corresponding one of the M memory elements. A designating circuit receives an address signal from an external device and designates one of the plurality of blocks of each of the M memory elements so that M blocks are designated by the address signal. A ROM stores information on whether or not each of the plurality of blocks of each of the M memory elements has a defective memory cell and outputs the information in accordance with the address signal. N external bus lines individually carry one-bit data. A bus line switching circuit determines whether each of the M blocks designated by the designating circuit has a defective memory cell by referring to the information from the ROM, and selectively connects N internal bus lines among the M internal bus lines to the N external bus lines so that one of the M blocks which has a defective memory cell is prevented from being selected and another one of the M blocks is selected.

The present invention generally relates to a semiconductor memory device, and particularly to a large capacity semiconductor memory device suitable for a storage device in a large-scale computer system. More particularly, the present invention is concerned with a semiconductor memory device having information indicative of the presence of defective memory cells (bits).
Conventionally, much effort to improve the production yield of semiconductor devices is being made. Presently, a technique which realizes 100% production yield is not available. It is possible to use only semiconductor memory devices having no defective memory cells. However, the number of defective memory cells increases with an increase in storage capacity and thus it is difficult to obtain a large number of semiconductor memory devices having no defective memory cells. From this point of view, a semiconductor memory device having redundant bits has been proposed. Such a semiconductor memory device has a memory cell array which is divided into a main memory cell array and a redundant memory cell array. Memory cells in the main memory cell are investigated by a conventional wafer probing test, and defective memory cells are detected. The detected defective memory cells are stored in a ROM (read only memory) provided in the semiconductor memory device. When a defective memory cell in the main memory cell array is addressed, a redundant bit in the redundant cell array is actually accessed instead of the addressed defective memory cell.
FIG. 1 is a block diagram of a conventional semiconductor memory device. The semiconductor memory device in FIG. 1 includes a memory cell array 10, which is divided into a main memory cell array 10a and a redundant memory cell array 10b. The main memory cell array 10a is accessed by a column decoder 11 and a row decoder 12a. The redundant memory cell array 10b is accessed by a redundant row decoder 12b and the column decoder 11. Normally, an address signal from an external circuit (not shown) such as a central processing unit (CPU) is supplied to the column decoder 11, and the row decoder 12a through a controller 13 and a switching circuit 14. Data are read out from or written into memory cells of the main memory cell array 10a corresponding to the address signal. The controller 13 compares the address signal with addresses stored in a read only memory (ROM) 13a. When it is determined that the address signal indicates a group of memory cells including a defective memory cell, the switching circuit 14 supplies the address signal from the controller 13 to the redundant row decoder 12b. A group of memory cells to be substituted for the group of memory cells having the defective memory cell is accessed by the column decoder 11 and the redundant row decoder 12b. Such a replacement is carried out in a row unit.
Memory cells forming the redundant memory cell array 10b must have no defective cells. Thus, the redundant memory cell 10b array is configured by only a limited number of memory cells having no defect. As a result, the redundant memory cell array 10b can save a limited number of defective memory cells in the main memory cell array 10a. In order to provide a large capacity less-expensive semiconductor memory device for use in a large-scale computer system, it is desired that a semiconductor memory device having a large number of defective memory cells be used. The conventional configuration shown in FIG. 1 cannot satisfy such a desire. In some cases, a large number of the elements each having the configuration shown in FIG. 1 is used for providing a large capacity semiconductor memory. In this arrangement, each element has the controller 13, the ROM 13a and the switching circuit 14. This prevents the memory device from being compactly made and operating at high speeds.

Semiconductor memory device having information indicative of presence of defective memory cell


A data storage system has a disk having a first, second and third zone. The first zone has rough texturing to prevent stiction between a slider at rest and the disk. The second zone has intermediate texturing to prevent stiction when a moving slider is in contact with the disk. The third zone has a smooth texture and is used for data recording. A control unit moves the slider between the zones as appropriate on power up and power down of the system. The system has an actuator latch having a bias device. The bias device allows the slider to be positioned between the first and second zones by selective energizing of the actuator while in the latched position.

1. Field of the Invention
This invention relates generally to magnetic recording disk data storage systems and more particularly to such systems having a plurality of surface zones.
2. Description of the Prior Art
Direct access storage devices (DASD), or disk drives, store information on concentric tracks of a rotatable magnetic recording disk. A magnetic head or transducer element is moved from track to track to record and read the desired information. Typically, the transducer element is positioned on an air bearing slider which flies above the surface of the disk as the disk rotates. In some recently proposed disk drives, the slider (xe2x80x9ccarrierxe2x80x9d) rides on a liquid film or bearing on the disk. A suspension assembly connects the slider to a rotary or linear actuator.
When the rotating magnetic disk of a disk drive is brought to a stopped condition, there is no aerodynamic cushion available to float or fly the slider above the surface. To prevent damage to the surface of the magnetic disk when it is not rotating, it is conventional to xe2x80x9cparkxe2x80x9d the slider in a landing zone so that contact with the disk by the slider will not cause any significant damage and will not destroy magnetically recorded data. However, simply parking the slider does not address the possibility that the disk drive might be impacted by a force sufficient to dislodge the actuator from its parked position, and thus move the slider onto the recording surface of the magnetic disk. Accordingly, it is important that the actuator which positions the slider be restricted or otherwise held in its parked position to prevent any scratching of the data recording region of the disk surface by the slider when there is no aerodynamic bearing between them.
Extremely smooth surfaces exist on both the data surface and the air bearing face of the slider. Without the aerodynamic cushion between the slider and the disk surface, the slider will come into contact with the stationary disk surface and stiction may result. Stiction occurs as two very smooth surfaces stick to each other and effectively prevent the removal of one from the other. The stiction forces may be sufficient to prevent the rotation of the disk. However, even if the disk can be rotated, damage almost certainly will occur to the surface of the disk due to the fact that the slider is in physical contact with and is initially stuck to the disk surface as the disk moves relative to the slider.
The slider can be parked in a landing zone or on an unload device such as a ramp. The actuator which moves the slider must be latched to prevent movement of the slider out of the parked position onto the data recording region of the disk.
Examples of latching devices include U.S. Pat. No. 5,363,261 issued Nov. 8, 1994, by Eckberg et al.; U.S. Pat. No. 4,833,550 issued May 23, 1989, by Takizawa et al.; U.S. Pat. No. 5,446,606 issued Aug. 29, 1995, by Brunneret al.; U.S. Pat. No. 5,117,318 issued May 26, 1992, by Immler et al.; U.S. Pat. No. 5,095,395 issued Mar. 10, 1992, by Wakatsuki; U.S. Pat. No. 4,562,500 issued Dec. 31, 1985 by Bygbnes; Japanese Application J1-166385 published Jun. 30, 1989 by Morita; Japanese Application J2-73581 published Mar. 13, 1990 by Okutsu; Japanese Application J4-26969 published Jan. 30, 1992 by Tamayama; Japanese Application J3-132980 published Jun. 6, 1991 by Sasaki; Japanese Application J2-146109 published Jun. 5, 1990 by Kadowaki; and Japanese Application J1-241070 published Sep. 26, 1989 by Morita.
The landing zone area of the disk is roughly textured to prevent stiction between the disk and the slider when the slider is at rest on the disk. An example of this texturing process is shown in U.S. Pat. No. 5,062,021 issued Oct. 29, 1991, by Ranjan et al. Other examples of textured landing zones include U.S. Pat. No. 5,446,606 by Brunner et al issued Aug. 29, 1995, and U.S. Pat. No. 4,907,106 by Yamada issued Mar. 6, 1990, and IBM TDB Vol. 28, No. 1, June 1985, P. 318.
A problem with the textured landing zone is that the bumps of the texturing tend to wear down with use. This is due to the fact that the slider is still in contact with the disk surface for a time as the disk rotates before the slider becomes airborne. Also, when the disk is in the process of stopping, the slider is in contact with the landing zone for a time before the disk comes to a complete stop. AS the bumps become worn away, stiction between the slider and the disk is more likely and this can result in failure of the system. Another problem encountered with the texturing landing zone is that wear between the slider and the textured zone may damage the delicate transducer head. Both of these problems will become more critical in the future as the slider flying height above the disk continues to decrease.
Briefly, in a preferred embodiment of the present invention, a disk drive system comprises a recording disk, a spindle motor for rotating the disk, an actuator for positioning a transducer/slider over the disk surface, and a control device. The disk has a data zone, a takeoff/landing zone (T/LZ) and a parking zone (PZ). The parking zone has a rough textured surface which prevents stiction between the slider and the disk. The takeoff/landing zone has a lightly textured surface.
The control device controls the actuator and spindle motor. During power-up, the slider is initially at rest on the surface of the parking zone. The spindle motor starts to rotate the disk and immediately thereafter the slider is moved to the takeoff/landing zone. The slider remains in this zone until the spindle motor reaches operating speed and the slider is airborne. Then the slider is moved to the data zone for normal operation.
Upon power-down, the procedure is reversed. The slider is moved to the takeoff/landing zone, the spindle motor is powered off and the disk rotation starts to slow. The slider lands on the takeoff/landing zone, making contact with the disk as the disk slows even more. Just before the disk stops rotating entirely, the slider is moved to the parking zone.
A latch mechanism is used to hold the actuator such that the slider is limited to a location proximate both the takeoff/landing zone and the parking zone. A bias spring in the latch automatically forces the slider over the parking zone when no actuator force is applied. This provides protection that no stiction will occur even when an emergency power failure occurs.
For a fuller understanding of the nature and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.

Multiple zone data storage system and method

International Business Machines Corporation


A fast spin echo NMR pulse sequence is modified to stabilize the magnitude of early NMR echo signals produced during each shot. Stabilization is accomplished by modifying the amplitude of the nutation angle produced in the spins by the corresponding RF refocusing pulses. When selective RF refocusing pulses are employed the slice is divided into subslices and the modifications are made separately to each subslice.

The field of the invention is nuclear magnetic resonance imaging methods and systems. More particularly, the invention relates to the reduction of image artifacts in fast spin-echo (FSE) pulse sequences by producing RF refocusing pulses which stabilize the magnitude of the acquired spin echo signals.
Any nucleus which possesses a magnetic moment attempts to align itself with the direction of the magnetic field in which it is located. In doing so, however, the nucleus processes around this direction at a characteristic angular frequency (Larmor frequency) which is dependent on the strength of the magnetic field and on the properties of the specific nuclear species (the magnetogyric constant .gamma. of the nucleus). Nuclei which exhibit this phenomena are referred to herein as "spins".
When a substance such as human tissue is subjected to a uniform magnetic field (polarizing field B.sub.0), the individual magnetic moments of the spins in the tissue attempt to align with this polarizing field, but process about it in random order at their characteristic Larmor frequency. A net magnetic moment M.sub.z is produced in the direction of the polarizing field, but the randomly oriented magnetic components in the perpendicular, or transverse, plane (x-y plane) cancel one another. If, however, the substance, or tissue, is subjected to a magnetic field (excitation field B.sub.1) which is in the x-y plane and which is near the Larmor frequency, the net aligned moment, M.sub.z, may be rotated, or "tipped", into the x-y plane to produce a net transverse magnetic moment M.sub.t, which is rotating, or spinning, in the x-y plane at the Larmor frequency. The practical value of this phenomenon resides in the signal which is emitted by the excited spins after the excitation signal B.sub.1 is terminated. There are a wide variety of measurement sequences in which this nuclear magnetic resonance ("NMR") phenomena is exploited.
When utilizing NMR to produce images, a technique is employed to obtain NMR signals from specific locations in the subject. Typically, the region which is to be imaged (region of interest) is scanned by a sequence of NMR measurement cycles which vary according to the particular localization method being used. The resulting set of received NMR signals are digitized and processed to reconstruct the image using one of many well known reconstruction techniques. To perform such a scan, it is, of course, necessary to elicit NMR signals from specific locations in the subject. This is accomplished by employing magnetic fields (G.sub.x, G.sub.y, and G.sub.z) which have the same direction as the polarizing field B.sub.0, but which have a gradient along the respective x, y and z axes. By controlling the strength of these gradients during each NMR cycle, the spatial distribution of spin excitation can be controlled and the location of the resulting NMR signals can be identified.
The present invention relates particularly to a method of spatial resolution of NMR signals known as slice selection. Slice selection involves the production of so-called "selective" RF excitation pulses in the presence of a magnetic field gradient to restrict the volume of spin excitation to a thin slab, or "slice." The frequency content and the magnitude of the selective RF excitation pulse determines the thickness and profile of the excited slice. The relationship between the selective RF excitation pulse and the spin excitation which results is described by John Pauly, et al. in "Parameter Relations for the Shinnar-Le Roux Selective Excitation Pulse Design Algorithm," published in IEEE Transactions on Medical Imaging, Vol. 10, No. 1, March 1991.
Most NMR scans currently used to produce medical images require many minutes to acquire the necessary data. The reduction of this scan time is an important consideration, since reduced scan time increases patient throughput, improves patient comfort, and improves image quality by reducing motion artifacts.
The concept of acquiring NMR image data in a short time period has been known since 1977 when the echo-planar pulse sequence was proposed by Peter Mansfield (J. Phys. C.10: L55-L58, 1977). In contrast to standard pulse sequences, the echo-planar pulse sequence produces a set of NMR signals for each RF excitation pulse. These NMR signals can be separately phase encoded so that an entire scan of 64 views, for example, can be acquired in a single pulse sequence of 20 to 100 milliseconds in duration. The advantages of echo-planar imaging ("EPI") are well-known, and a number of such sequences have been proposed and are disclosed in U.S. Pat. Nos. 4,678,996; 4,733,188; 4,716,369; 4,355,282; 4,588,948 and 4,752,735.
A variant of the echo planar imaging method is the Rapid Acquisition with Relaxation Enhancement (RARE) sequence which is described by J. Hennig, et al. in an article in Magnetic Resonance in Medicine 3,823-833 (1986) entitled "RARE Imaging: A Fast Imaging Method for Clinical MR." The essential difference between the RARE sequence and the EPI sequence lies in the manner in which echo signals are produced. The RARE sequence utilizes RF refocused echoes generated from a Carr-Purcell-Meiboom-Gill sequence, while EPI methods employ gradient recalled echoes.
Both of these "fast spin echo" imaging methods involve the acquisition of multiple spin echo signals from a single excitation pulse in which each acquired echo signal is separately phase encoded. Each pulse sequence, or "shot," therefore results in the acquisition of a plurality of views and a plurality of shots are typically employed to acquire a complete set of image data. For example, a RARE pulse sequence might acquire 8 or 16 separate echo signals, per shot, and an image requiring 256 views would, therefore, require 32 or 16 shots respectively.
It is well known that the RARE sequence, and particularly its slice selective implementation, suffers from a non-steady state behavior in the first NMR echo signals acquired during each shot. This is particularly true when the selective RF refocusing pulses are not exactly 180.degree.. This has led to the inclusion of additional RF refocusing pulses at the beginning of the pulse sequence to allow equilibrium to be achieved before data acquisition begins as proposed by Gary H. Glover, et al. in "Reduction of Non-equilibrium Effects in RARE Sequences," 10th SMRM Proceedings 1991 WIP p. 1242, and RSNA 1991 Book of Abstracts p. 142. While this may reduce image artifacts, it does so with a resulting increase in total scan time.

Stabilized fast spin echo NMR pulse sequence


An oil-cooled screw compressor which can maintain the discharge temperature of discharge gas at an appropriate level is provided. The oil-cooled screw compressor comprises a compressor body, an oil separation/recovery unit disposed in a discharge path extending from a discharge port of the compressor body, and an oil feed path extending from the oil separation/recovery unit and communicating with the compressor body 12. The oil feed path is branched at an intermediate position thereof into a first feed path portion and a second feed path portion. An opening/closing valve is disposed in the first feed path portion, a pressure gauge is disposed in the discharge path, and a control unit is provided to control opening and closing of the opening/closing valve on the basis of a correlation between a discharge pressure detected by the pressure gauge and a predetermined pressure.

1. Technical Field of the Invention
The present invention relates to an oil-cooled compressor which is constructed so that oil is fed to a body of the compressor for lubrication, cooling, or shaft sealing. Particularly, the invention is concerned with an oil-cooled compressor in which the discharge temperature of discharge gas is controlled appropriately by controlling the amount of oil to be fed.
2. Description of the Related Art
There is known an oil-cooled compressor constructed such that oil is fed to a body of the compressor for lubrication, cooling, or shaft sealing. An example in which this known oil-cooled compressor is an oil-cooled screw compressor will now be described with reference to drawings attached hereto. FIG. 4 is a schematic system diagram of an oil-cooled screw compressor, FIG. 5 is a graph explaining a relation between a discharge pressure Pd and a power w of a compressor body and a relation between the discharge pressure Pd and an oil quantity q, and FIG. 6 is a graph explaining a relation between the discharge pressure Pd and a discharge temperature Td.
A description will first be given of a conventional oil-cooled screw compressor. The numeral 2 in FIG. 4 denotes an oil-cooled screw compressor. The screw compressor 2 is provided with a compressor body 12 in which a pair of intermeshing male and female screw rotors 11 is accommodated rotatably. A discharge path 13 extends from a discharge port of the compressor body 12, and an oil separation/recovery unit 14 as an oil separating means is disposed in the discharge path 13. An oil separating unit 15 is provided at an upper position within the oil separation/recovery unit 14. A lower portion of the oil separation/recovery unit 14 serves as an oil sump 16 for staying therein of oil after separation by the oil separating element 15. On one end of an oil feed path 18 with an oil cooler 17 disposed therein is connected to the oil sump 16, while the opposite end thereof is in communication with the compressor body 12.
Thus, the oil-cooled screw compressor 2 is constructed so that oil which has flowed through the oil feed path 18 from the oil sump 16 in the oil separation/recovery unit 14 and cooled by the oil cooler 17 is fed to a rotor chamber, bearings and a shaft sealing portion located within the compressor body 12. (The rotor chamber, bearings and a shaft sealing portion are not shown in the figures) An oil quantity q of oil fed to the compressor body 12 of the oil-cooled screw compressor 2 varies depending on a discharge pressure Pd of the compressor body 12. A relation between the oil quantity q and the discharge pressure Pd is as shown by the following equation (1). A nozzle area of a communicating portion of the oil feed path 18 for communication with the compressor body 12 is assumed to be S.q=C1×S×(Pd)1/2  (1)In the above expression (1), C1 is a constant.
The power w of the compressor body 12 can be calculated by the following equation (2):W=C2×{(Vi−κ)/(κ−1)×Ps+Pd/vi}  (2)
In the equation (2), C2 is a constant, vi is an internal volume ratio, κ is a specific heat ratio of air, PS is a suction pressure. The oil quantity q and power w of the compressor body 12 vary as shown schematically in FIG. 5. The discharge temperature Td can be calculated from the following equation (3):Td=w/(C3×q)+To  (3)In the equation (3), To is a feed oil temperature and C3 is a constant.
From the equations (1) and (2) it is seen that the oil quantity q is in a linear relation to the square root of the discharge pressure Pd, while the power w is in a linear relation to the discharge pressure Pd itself. From this fact it can be said that with respect to increase and decrease of the same discharge pressure Pd, the ratio of the increase and decrease quantity q of oil fed to the compressor body is larger than that of the power w. Further, from the equation (3) it can be said qualitatively that the discharge temperature Td rises as the discharge pressure Pd decreases, as shown in FIG. 6.
As to the discharge pressure Pd in the compressor body of the oil-cooled compressor, a maximum discharge pressure Pdmax is established in relation to the specification of the oil-cooled compressor. A higher pressure than Pdmax cannot (or does not) exist. There also is established a lowest discharge pressure Pdmin. A lower pressure than Pdmin cannot (or does not) exist.
As to the discharge temperature Td of discharge gas discharged from a discharge port formed in the compressor body of the oil-cooled compressor, there are established a desirable upper-limit discharge temperature Tdmax and a desirable lower-limit discharge temperature Tdmin. Generally, the upper-limit discharge temperature Tdmax is established (e.g., 100° C.) for preventing the deterioration of oil, and the lower-limit discharge temperature Tdmin is established for preventing the deposition of drain on the discharge side of the compressor body (e.g., 80° C.).
In order to ensure the lower-limit discharge temperature Tdmin at the upper-limit discharge temperature Tdmax, a corresponding value of oil quantity q is determined so as to bring about this state and the discharge pressure Pd is decreased in the state of that oil quantity q. As a result, the discharge temperature Td drops for the reason stated above in connection with the equations (1), (2) and (3). At the initial stage, a certain degree of temperature rise does not give rise to any problem because the discharge temperature is set to the lower-limit discharge temperature Tdmin. As to a more increase of temperature, there can be a case where the temperature rises up to near the upper-limit discharge temperature Tdmax or may exceed the upper-limit discharge temperature, which would cause inconvenience in the operation of the compressor body.
It is preferable for preventing the deterioration of oil that the temperature of oil fed to the compressor body of the oil-cooled compressor be lower than the upper-limit discharge temperature Tdmax, more preferably be maintained at a low temperature. Also, for preventing the deposition of drain from the compressed gas, it is preferable that the oil temperature be kept higher than and close to the lower-limit discharge temperature Tdmin.
Japanese laid-open patent gazette JP-8-4679-A discloses control of the discharge temperature of a compressor in order to prevent the production of drain. However, the compressor in the prior document has a complicated structure which additionally includes a discharge temperature sensor and an oil control valve changing supply oil quantity continuously. In addition, though it is assumed that a complicated control algorithm should be applied for thus complicated structure, the prior document discloses nothing about the control algorithm.


Certain disclosed embodiments concern a method and an apparatus for determining molecular structure. One embodiment comprises producing sample ions from a sample, cooling molecules of the sample ions by either embedding sample ions in superfluid droplets, such as superfluidic helium droplets, or subjecting sample ions in a cooled ion trap, to a selected temperature approaching absolute zero. Plural cooled sample ions confined in a diffraction zone are oriented using a laser, and a diffraction image is produced from oriented sample ions using an electron beam. Molecular structure is determined using collected images from different orientations obtained under different polarization directions of the orientation laser. Embodiments of an apparatus for determining molecular structure also are disclosed. The apparatus operation, data accumulation and processing are controlled by software. The software can directly calculate electron density maps without using heavy atom derivatives or multi-wavelength anomalous dispersion phasing methods.

The human genome has been known for a decade, but the information provided by the genome has had only a relatively modest impact upon understanding mechanisms of disease or how mutations affect function. While the DNA sequence from a genome provides information about the linear order of the amino acid constituents of proteins, limited tools are available to understand how proteins twist and fold into their functional forms. The folded shapes of proteins determine how they function in healthy tissue, how they misfold to cause disease, and how drugs bind to proteins to modulate function.
Billions of dollars have been invested to develop instrumentation to support structural determination of biological molecules. The successes are remarkable and the results are made available online through the Protein Data Bank. Currently, the gold standard of structure determination is x-ray crystallography. However, the method requires considerable technical prowess, needs high concentrations of pure protein, and frankly depends upon a fair amount of luck. Ultimately the success of crystallography is determined by the availability of a micrometer sized defect free single crystal. This barrier has posed a tremendous limitation on the progress of biological research. For example, more than half of all proteins and 95% of integral membrane proteins do not crystallize. Thus, their structures cannot be determined by crystallography. Other alternative methods including NMR, cryoelectron microscopy, and neutron diffraction, have had limited successes. Altogether, these methods have only contributed to ˜10% of all the structures deposited in the protein data bank.

Apparatus and method for determining molecular structure


In a first preferred embodiment of a thermal rotary actuator constructed according to the present invention, an actuator body includes first and second spaced, parallel linear actuator elements each linear actuator element having a respective predetermined coefficient of thermal expansion (CTE) and respective first and second ends defining the linear actuator element length. The linear actuator elements, in response to a selected temperature differential therebetween, are thereby subject to a predetermined length differential. Means are provided for effecting the selected temperature differential in the first and second linear actuator elements to thereby effect the predetermined length differential. First yoke means, attached to the first ends of the first and second linear actuator elements, include fixing means for fixing the first ends in a predetermined spatial relationship, and means for flexibly attaching said fixing means to the reaction structure. Second yoke means are attached to the second ends of the first and second linear actuator elements and include means for flexibly attaching the moveable object to the second ends of the first and second linear actuator elements. The second yoke means, in response to said length differential, thereby translates the predetermined differential length to a proportional displacement of the moveable element. Second and third preferred embodiments include the addition of an auxiliary flexure system in the second yoke means.

The present invention relates to displacement actuators and in particular to a thermally-activated displacement actuator useable in means for effecting temperature-compensation of, for example, the focal length of optical elements in an optical assembly.
Low-resolution, thermally-activated displacement actuators are commonly used on household appliances and automobiles as safety devices or as controllers of motion functions. A commonly-employed technique for effecting linear motion is to heat or cool a fluid confined within a cylinder having a moveable piston. The piston moves as the actuating fluid expands or contracts, as illustrated in U.S. Pat. No. 4,055,954. Control of actuator position by a temperature control based on position feedback is shown in U.S. Pat. No. 4,081,963. Another type of thermally-activated actuator employs phase changes in a force-generating medium to apply a force on a piston. The large volume difference between solid and liquid wax is disclosed in U.S. Pat. No. 5,025,627 wherein actuation is controlled via a thermoelectric cooler (TEC) based on position feedback. A volume difference in solid phases is disclosed in U.S. Pat. No. 4,553,393 wherein memory metal beams of binary weighted stiffness are resistively heated to cause a phase change, thereby creating a force proportional to the element axial stiffness. Still another type of thermally-activated actuator relies on expansion and contraction of solid members to achieve rotary motion, such as may be found in thermostats and automatic choke devices, wherein bimetallic springs produce rotary motion.
However, certain systems require precise displacement of a moveable mechanical or optical element to effect or maintain the accuracy or resolution of the system. For example, in a high-resolution optical imaging system, such as may be found in a laser output scanner, a stable, monochromatic collimated light beam must be provided by a beam source that typically includes a laser diode and a collimating lens. For adequate optical performance, the beam source must maintain a predetermined beam quality over a wide ambient temperature range. In conventional approaches, the laser diode and lens are mounted in a mechanical structure that attempts to maintain the beam focal length while the apparatus undergoes ambient temperature-induced structural changes. The thermal compensation of the beam focal length is typically effected either passively or actively.
Passive compensation systems rely on the differences in coefficients of thermal expansions of the various elements in the optical system such that there is a mechanical movement to minimize the net focus shift over a narrow ambient temperature range. One such conventional approach is to employ concentric tube systems, which, if constructed from common materials, are too large or bulky. For example, U.S. Pat. No. 4,730,335 discloses a series of interlocking tubes each carrying a single optical element of an optically-pumped solid-state laser. Such an apparatus can compensate only for a relatively narrow range of ambient temperature changes, and is too large to be suitable for many applications.
Conventional active compensation systems (wherein, for example, heating elements or thermoelectric coolers are used) have other disadvantages. For example, a thermoelectric cooler is employed in the apparatus disclosed in U.S. Pat. No. 4,604,753 to stabilize the output power and wavelength of a laser diode beam source; U.S. Pat. Nos. 4,656,635 and 4,993,801 disclose a beam source wherein a thermoelectric cooler is employed to control the operating temperature of the entire head. These apparatus are more complex and expensive to construct, and offer less accurate displacement, than is desired for certain applications, including the aforementioned laser output scanner application.

Thermally-controlled rotary displacement actuator operable for precise displacement of an optical or mechanical element


Ceramic catalyst carriers that are mechanically, thermally and chemically stable in a ionic salt monopropellant decomposition environment and high temperature catalysts for decomposition of liquid high-energy-density monopropellants are disclosed. The ceramic catalyst carrier has excellent thermal shock resistance, good compatibility with the active metal coating and metal coating deposition processes, melting point above 1800° C., chemical resistance to steam, nitrogen oxides and acids, resistance to sintering to prevent void formation, and the absence of phase transition associated with volumetric changes at temperatures up to and beyond 1800° C.

Thrust is produced in a monopropellant thruster, or reaction engine, in the following stages: (1) A monopropellant fluid (liquid or gaseous) that is usually pressurized is injected onto a catalyst bed. (2) When the monopropellant comes in contact with the catalyst it decomposes, or ignites. Decomposition of the monopropellant may occur in one reaction or in multiple sequential reactions. Then (3) the decomposition products are exhausted through the exit cone or nozzle to create thrust. The thrust, or specific impulse, is dependant on many variable including engine design, size, and energy produced by propellant decomposition.
A typical monopropellant catalyst consists of discrete active metal particles dispersed on a ceramic carrier, or substrate. The active metal particles catalyze, or reduce the activation energy for, monopropellant decomposition upon contact. The purpose of the catalyst substrate is to (i) increase the surface area of active metal to provide more sites for propellant decomposition and (ii) stabilize the active metal particles, i.e., prevent them from migrating or sintering, which leads to particle growth and/or loss of active metal surface area. During thruster operation, the substrate is exposed to the propellant and intermediate species that form during propellant decomposition as well as decomposition products that are extremely corrosive, particularly at elevated temperatures (>1000° C.). This leads to degradation of the substrate, followed by catalyst deactivation. A long life monopropellant catalyst must be composed of a substrate that is resistant to corrosion from the propellant and its decomposition products and intermediate species and resistant to degradation under thruster operating conditions.
Reduced toxicity high-energy-density ionic salt monopropellants, including but not limited to monopropellants containing an oxidizer such as hydroxylammonium nitrate (HAN, [HO—NH3+]NO3−) and one or more fuels in highly concentrated solutions containing water, ethanol or a suitable solvent or without a solvent are described as replacements for hydrazine-based propellants. The new monopropellants, which will hereinafter sometimes be referred to as ionic salt monopropellants or high-energy-density ionic salt monopropellants and which include HAN-based ionic salt monopropellants, offer lower toxicity, lower flammability, lower vapor pressure, lower freezing-point temperature, and higher density-specific impulse than hydrazine-based monopropellants.
Liquid monopropellants, including but not limited to HAN-based ionic salt monopropellants, can be decomposed by passing them over a solid catalyst bed. The catalyst decreases the activation energy required for monopropellant decomposition, thus allowing for combustion at lower temperatures than required for pure thermal decomposition. However, the decomposition and combustion reactions degrade the catalyst. As a result, a typical monopropellant thruster can only be fired for a limited number of pulses, or until the catalyst fails due to loss of catalytic mass or loss of catalyst activity as described above.
The high-adiabatic-decomposition-temperatures of the described HAN-based ionic salt monopropellants render conventional catalysts ineffective when applied to these formulations. The adiabatic flame temperature of the HAN-based ionic salt monopropellants exceeds 1800° C., whereas hydrazine possesses an adiabatic flame temperature of only 900° C. In addition, decomposition of the HAN-based ionic salt monopropellants produces highly oxidizing species such as oxygen (O2), acidic species such as HNO3, and water vapor that are highly corrosive to metals as well as ceramics such as alumina (Al2O3) that are typically used in conventional catalysts.
Use of high-energy-density ionic salt monopropellants, including ionic salt monopropellants, as a replacement for the current state-of-art hydrazine monopropellant can potentially increase thruster performances. However, use of hot burning high-energy-density ionic monopropellants requires use of catalysts, chamber materials, and bed plates in the thruster/reaction engine that can survive in the monopropellant decomposition environment at temperatures exceeding 1600° C. and as high as 2000° C.
Conventional, prior art catalysts such as Ir/Al2O3, Pt/Al2O3, LCH-210, LCH-207, LCH-227, Shell 405 or S-405 that were developed for use with hydrazine cannot withstand the higher operating temperatures and the more corrosive environment encountered in decomposing high-energy-density HAN-based ionic salt monopropellants.
ZrO2 is an amphoteric refractory oxide and has demonstrated a good acid resistance in HAN thruster environments. However, it suffers from a destructive tetragonal-to-monoclinic phase transformation due to a volumetric change of 3%-5% or more associated with this phase transformation. Repeated heating and cooling cycles, such as those encountered in a rocket engine, would result in a complete loss of the mechanical integrity of ZrO2.
Stabilizers, typically MgO, CaO, Y2O3, La2O3 or CeO2, are added in necessary concentrations to fully stabilize ZrO2 in the cubic phase or to partially stabilize ZrO2 in tetragonal phase to provide transformation toughening and prevent the spontaneous tetragonal-to-monoclinic phase transformation and destruction of the material that would otherwise occur upon heating and cooling over a given temperature range as described above. However, these stabilizers are all basic and are susceptible to acid-base reactions in acidic environments such as those encountered in rocket engines operating with ionic salt-based monopropellants. Partially stabilized (t-ZrO2) or fully stabilized (c-ZrO2) goes through an aging process where the basic stabilizers come out of solid solution and subsequently react with the acidic species in the HAN thruster environment. This acid-base reaction effectively removes the basic stabilizer from the zirconia and thus increases the rate of precipitation of the stabilizers from ZrO2 and accelerates the aging and destabilization of ZrO2. The sequence of precipitation and removal by acid-base reaction prevents the basic stabilizer, once precipitated, from going back into solid solution with ZrO2 upon heating and re-stabilizing the material. In addition, some of the conventional stabilizers mentioned here, such as MgO and CaO, are extremely hydrophilic and thus after precipitation from ZrO2 may potentially be removed from the material in the presence of water vapor or steam that can exist in the thruster environment.
Problems observed during rocket engine tests containing conventional catalysts with new monopropellants include excessive sintering of catalyst, void formation, increase in pressure drop, fracturing of catalyst granules, fine formation, fragmentation of the catalyst granules due to thermal shock, leaching of the catalyst by acids, and rapid loss of catalyst activity. Catalysts such as LCH-237 and Sienna's SSC-0103 that consist of an Ir coated ZrO2-based carrier containing traditional stabilizers such as CeO2, Y2O3, or CaO can provide over 30 minutes of lifetime but some missions require longer lifetimes. The lifetime of these catalysts are limited by the aging of the stabilized ZrO2 carriers, and leaching of the stabilizers by acids or steam during service that leads to fracturing of catalyst granules, fine formation, fragmentation of the catalyst granules due to thermal shock, and rapid loss of catalyst activity.
Ceramic materials that have been evaluated as catalyst carriers for use with HAN-based ionic salt monopropellants include transition metal oxides such as Al2O3, TiO2, ZrO2, CeO2—ZrO2, Y2O3—ZrO2 (Kirchnerova, J., Klvana, D. (2000) "Design Criteria for High Temperature Combustion Catalysts," Catalysis Lett, Vol. 67, p. 175), refractory carbides and nitrides such as SiC and Si3N4 (Rodrigues, J. A. J et al., (1997), "Nitride and Carbide of Molybdenum and Tungsten as Substitutes of Iridium for the Catalyst Used for Space Communication", Catalysis Lett., Vol. 45, P. 1-3), transition metal-based and alkaline earth-based perovskites (Savrun, E. and Schmidt, E. W., (2001), "High Temperature Catalyst for Nontoxic Monopropellant", Air Force Research Laboratories SBIR Phase I Final Report, AFRL-PR-ED-TR-2001-0012; Savrun, E. et al., "Novel Catalysts for HAN/HEHN Based Monopropellants", NASA Glenn Research Center SBIR Phase I final Report, NAS3-02025) and transition metal substituted lanthanum-strontium hexaaluminates (Tejuca, L. G., Fierro, J. L. G., and Tascon, J. M. D., (1989) "Structure and Reactivity of Perovskite-Type Oxides", Adv. Catalysis, Vol. 36, P. 237). The combined stabilizing effects and corrosion resistance of In2O3 in ZrO2 are cited in U.S. Pat. No. 5,288,205 to Jones, R., 1994, "India-stabilized Zirconia Coating for Composites," and in the following reference: Jones, R. L. and Mess, D. 1992, "India as a Hot Corrosion-Resistant Stabilizer for Zirconia," Journal of American Ceramics Society, volume 75, pages 1818-1821. The combined stabilizing effects and corrosion resistance of Sc2O3 in ZrO2 are cited in Jones, R. L., 1989 "Scandia-stabilized Zirconia for Resistance to Molten Vanadate-sulfate Corrosion," Surface and Coatings Technology, volume 39/40, pages 89-96. The combined stabilizing effects and corrosion resistance of SnO2 in ZrO2 are cited in U.S. Pat. No. 5,312,585 to Jones, R. L., 1994, "Corrosion Inhibition in High Temperature Environment". The combined stabilizing effects of Ga2O3 in ZrO2 and its resistance to water or steam are cited in U.S. Pat. No. 5,279,995 to Hiroaki Tanaka et al., 1994, "Zirconia Ceramics."

Corrosion resistant catalysts for decomposition of liquid monopropellants


A method and system for preparing a light transmitting and electrically conductive oxide film. The method and system includes providing an atomic layer deposition system, providing a first precursor selected from the group of cyclopentadienyl indium, tetrakis (dimethylamino) tin and mixtures thereof, inputting to the deposition system the first precursor for reaction for a first selected time, providing a purge gas for a selected time, providing a second precursor comprised of an oxidizer, and optionally inputting a second precursor into the deposition system for reaction and alternating for a predetermined number of cycles each of the first precursor, the purge gas and the second precursor to produce the oxide film.

Indium oxide (In2O3), tin oxide (SnO2) and indium tin oxide (ITO), have substantial advantages for use as transparent conducting oxides which are employed, for example, in optoelectonic devices, flat panel displays and photovoltaic devices and which are also useful in gas sensors and as catalysts. In these types of applications, it can be helpful for device performance to have precise control over film thickness and composition, and some applications require the ability to coat high aspect ratio geometries or porous materials. In2O3 thin films can be deposited using a variety of methods including sputtering, chemical vapor deposition, and atomic layer deposition (ALD). Of these techniques, ALD shows the most significant promise as this method affords excellent control over both the thickness and the composition of the deposited film. Most importantly, ALD offers excellent deposition conformality that enables the coating of porous materials with aspect ratios in excess of 1000.
Previously, In2O3 deposition by ALD has been accomplished using InCl3 with either H2O or H2O2 as the oxygen source. Although useful for coating planar surfaces, this method suffers from several limitations. First, the InCl3 chemistry requires high growth temperatures of ˜300-500° C. and yields a low growth rate of only 0.25-0.40 Å/cycle. In addition, the InCl3 has a very low vapor pressure and must be heated to 285° C. just to saturate a planar surface. Furthermore, the corrosive HCl byproduct can damage the deposition equipment. But the greatest limitation of the InCl3/H2O method, especially for coating nanoporous materials, is that InCl3 can etch the deposited In2O3. Consequently, nanoporous materials require very long precursor exposures that are likely to completely remove the In2O3 from the outer portions of the nanoporous substrate.
An improved ALD process for In2O3 has also been sought for many years and a number of alternate precursors have been investigated including β-diketonates (In(hfac)3 (hfac=hexafluoropentadionate), In(thd)3 (thd=2,2,6,6-tetramethyl-3,5-heptanedioneate), and In(acac)3 (acac=2,4-pentanedionate)) and trimethyl indium, (In(CH3)3). Unfortunately, these efforts were unsuccessful. No growth was observed using β-diketonates with water or hydrogen peroxide, while trimethyl indium did not yield self-limiting growth.

Synthesis of transparent conducting oxide coatings


Integrated circuit devices include data inversion circuits therein that are configured to evaluate at least first and second ordered groups of input data in parallel with an ordered group of output data previously generated by the data inversion circuit. The data inversion circuit is further configured to generate inverted versions of the first and second ordered groups of input data as versions of the first and second ordered groups of data in parallel at outputs thereof whenever a number of bit differences between the first ordered group of input data and the ordered group of output data is greater than one-half a size of the first ordered group of input data and a number of bit differences between the second ordered group of input data and the version of the first ordered group of input data is greater than one-half a size of the second ordered group of input data, respectively.

Integrated circuit devices that support high data bandwidth may suffer from simultaneous switching noise (SSN), particularly when switching a plurality of output pins or driving groups of parallel signal lines (e.g., buses) at high frequency. Conventional techniques to reduce SSN have included the use of data inversion circuits that operate to limit the number of parallel data signals that switch value during consecutive data output cycles. For example, FIG. 1 illustrates a conventional data inversion circuit 10 that includes an input XOR circuit 11, a data comparator 13 and an output XOR circuit 12. The input XOR circuit 11 receives a plurality of current input signals FDO1-FDO8 and a plurality of prior output signals DO1-DO8, which are fed back from parallel output pins of the data inversion circuit 10. The XOR logic gates within the input XOR circuit 11 generate a plurality of signals that are provided to inputs of the data comparator 13. This data comparator 13 is configured to generate a single flag signal (FLG) having a logic value equal to 1 whenever a number of bit differences (Δ) between the data pairs (FDO1, DO1), (FDO2, DO2), (FD31, DO3), (FDO4, DO4), (FDO5, DO5), (FDO6, DO6), (FDO7, DO7) and (FDO8, DO8) is greater than or equal to four (4). This flag signal may also be referred to as a parity signal (S). Thus, if the prior value of DO1-DO8=[00000000] and the new value of FDO1-FDO8=[11111110], then the flag signal FLG will have a value of 1 because Δ=7. In this case, the new output signals DO1-DO8 will equal [00000001], which means that only one of the output pins will switch value between the old and new output signals. The flag signal FLG will also be provided as an output of the data inversion circuit 10 so that the circuit or device receiving the output signals can properly interpret their values. In contrast, if the prior value of DO1-DO8=[00001111] and the new value of FDO1-FDO8=[00000001], then the flag signal FLG will have a value of 0 because Δ=3. In this case, no data inversion operation will be performed by the output XOR circuit 12 and the new output signals DO1-DO8 will be generated as [00000001].
As will be understood by those skilled in the art, the receipt of this flag signal FLG at the inputs of the NOR gates within the output XOR circuit 12 may be delayed relative to the leading edges of the current input signals FDO1-FDO8, which are evaluated when determining the value of the flag signal FLG. In particular, a sum of the timing delays generated by the input XOR circuit 11 and the data comparator 13 may equal the delay between the leading edges of the current input signals FDO1-FDO8 and the leading edge of the flag signal FLG received by the output XOR circuit 12. This delay may operate to reduce the width of the data valid window that is present at the outputs of the output XOR circuit 12 and thereby reduce a maximum operating frequency of the data inversion circuit 10.
Another conventional technique for reducing SSN in integrated circuits that output parallel signals to a data bus is disclosed in U.S. Pat. No. 5,931,927 to Takashima. In particular, FIG. 3 of the '927 patent illustrates an input/output device that generates an m-bit data signal and a single bit parity signal to a bus. Half of the m-bit data signal may be inverted if necessary to make the number of "1" signal values more nearly equivalent to the number of "0" signal values that are generated during an output cycle. In particular, the '927 patent shows a Circuit A (left side) and a Circuit A (right side), with each circuit receiving ½ m bits of data. If the Circuit A (left side) and the Circuit A (right side) all receive logic 1 signals, then the parity outputs from the two circuits will be equal to "1", which reflects the fact that more "1s" than "0s" are present. When this occurs, a data inversion flag, which is generated by an exclusive XNOR gate, will be set to a logic 1 value. When the data inversion flag is set to a logic 1 value, then the outputs of the Circuit A (right side) will be inverted by the data inversion circuit. Accordingly, the output buffer (left side) will receive all "1s" from the Circuit A (left side) and the output buffer (right side) will receive all "0s" from the data inversion circuit. A single-bit output buffer will also generate a flag signal (F1) so that the inversion of the data from the Circuit A (right side) can be properly interpreted once the data is passed to the bus.
Thus, in FIG. 3 of the '927 patent, if the m-bit data signal provided to circuit A (left side) and circuit A (right side) during a first cycle is: 11111000 and 00000111 and the m-bit data signal provided during a second cycle is: 00000111 and 11111000, then the data inversion flag will not be set and the m-bit data provided to the bus during consecutive cycles will be:
1st cycle:1111100000000111↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓2nd cycle:0000011111111000Δ = 16
Thus, using the circuit of FIG. 3 of the '927 patent, the number of "1s" and "0s" generated during the first cycle are equivalent (at eight each) and the number of "1s" and "0s" generated during the second cycle are also equivalent (at eight each). However, the number of bit differences (Δ) from the first cycle to the second cycle will equal a maximum of sixteen (i.e., A=16), which means that all output signal lines to the bus will be switched high-to-low or low-to-high when passing from the first cycle to the second cycle. This high level of switching can lead to unacceptable simultaneous switching noise, even if the total number of "1s" and the total number of "0s" during the first and second cycles is maintained at about an equivalent level.
Accordingly, notwithstanding these conventional techniques for reducing simultaneous switching noise, there continues to be a need for data inversion circuits that can handle high data bandwidths with high degrees of immunity from SSN. There also continues to be a need for data inversion circuits that can operate at high frequency.

Integrated circuit devices having data inversion circuits therein with multi-bit prefetch structures and methods of operating same


A battery driven electric lawn mower includes a DC motor, and mowing blade on an output shaft of the motor. A control unit is connected between the motor and the battery for increasing and decreasing the electric current supplied to the motor in accordance with an increase and decrease in load, to thereby maintain the number of revolutions per second of the motor substantially constant at or near a minimum value permitting a mowing blade to function normally under a heavy load. The control unit comprises an electric current detecting device for detecting a load current flowing in the motor, and a pulse generating device for outputting a pulse signal having a pulse width corresponding to an electric current value detected by the electric current detecting device. A pulse-responsive switch device for adjusting the electric current supplied to the motor in response to a pulse signal output from the pulse generating device. The pulse responsive switch device is connected in series with the motor. A duty ratio of the pulse signal output from the pulse generating device is increased in accordance with an increase in electric current detected by the electric current detecting device.

1. Field of the Invention
The present invention relates to an electric lawn mower of a battery driven type, comprising a DC motor provided at an output shaft thereof with a mowing blade, and a battery connected to the DC motor.
2. Description of the Related Art
The demand for electric lawn mowers has significantly increased in recent years, particularly in the suburbs because of the fact that electric mowers make less noise and produce less pollution than gas-powered lawn mowers.
Electric lawn mowers include a battery driven type (DC type) and a power cord type (AC type). The AC type is popular due to the fact that a reliable power source can easily be insured. However, the power cord or AC type is inconvenient to handle, because a power cord must be dragged around the lawn during mowing, and additionally, the power cord has a drawback that its working area is limited due to a limit in the length of the power cord.
By contrast, the battery driven type (for example, see Japanese Patent Application Laid-open Nos. 4-360615 and 5-192027) is easy to handle, because it does not have a cord which must be dragged around, and moreover, the working site is not limited. On the other hand, however, the battery driven type has a drawback that the battery capacity is limited, whereby the working time or the area to be mowed must be limited, and in actuality lawn mowing can only be carried out in a small area with an amount of electricity charged in the battery in single charge.
In a conventionally known electric lawn mower disclosed, for example, in Japanese Patent Application Laid-open No. 5-192027, there is provided a revolution-number sensor mounted to an output shaft of a motor or to a driving shaft for a mowing blade in order to maintain the number of revolutions of the motor at a certain constant value during working by the lawn mower. An electric current supplied to the motor is controlled in response to a signal output from the sensor. In such a lawn mower, however, the revolution-number sensor and the wiring connected thereto are typically located in rugged environments where there is dust, dirt, mud, water, and lawn cuttings scooped up by the mowing blade. For this reason, dust-proof and water-proof means must be provided for the sensor and the wiring. A significant increase in cost is incurred as a result, which is in addition to the expense of the sensor.


A system for an aircraft includes an aircraft component that includes a heater routed through the aircraft component, the heater including a resistive heating element and insulation surrounding the resistive heating element. A first current flows into the resistive heating element to provide heating for the aircraft component and a second current flows out of the resistive heating element. The system further includes a first sensor configured to produce a first sensor signal representing the first current, a second sensor configured to produce a second sensor signal representing the second current, a leakage sensor configured to produce a leakage sensor signal representing a leakage current, and a signal processor configured to sample and measure the first current, the second current, and a leakage current using a high frequency sampling rate to identify the presence of electric arcing. The detection of electric arcing is used to predict future heater failure and estimate heater remaining useful life.

The present disclosure relates generally to probes, and in particular to prognostics for air data probes.
Probes are utilized to determine characteristics of an environment. In aircraft systems, for example, air data probes may be implemented on the external portions of the aircraft to aid in determination of conditions such as airspeed, altitude, and angle of attack, among others. Due to the harsh conditions of flight at high altitudes, ice may build-up on portions of the air data probe. To combat this, heaters are implemented within the air data probe to prevent the formation of ice that may impact proper functionality of the air data probe.
When air data probes break down, they need to be replaced, often prior to a subsequent takeoff. The heater of an air data probe is often the most life-limited part. Therefore, air data probes need to be replaced as soon as the heater breaks down. It is desirable to predict when the air data probe will require replacement.

Electric arc detection for probe heater PHM and prediction of remaining useful life


The present invention relates to a process for purifying recombinant coagulation factor VIII by loading an aqueous solution containing factor VIII onto a hydrophobic interaction chromatography (HIC) gel, wherein at least one surfactant is present in the aqueous solution and/or a buffer solution used to equilibrate the gel prior to loading the aqueous solution onto the gel. The presence of a surfactant when loading the solution containing factor VIII onto the HIC gel, makes it possible to efficiently separate the intact and active factor VIII molecules from molecules with structural deviations. With the present invention it is further possible to reduce the content of DNA and/or CHO cell contaminants considerably and increase the activity of the factor VIII product to a hitherto unknown extent. The invention further relates to an aqueous solution containing recombinant factor VIII which has been purified according to the present process and use of such an aqueous solution, for the manufacture of a medicament for administration to a patient having the symptoms of hemophilia. Also, the invention relates to a method for treatment of hemophilia by administration of a therapeutically effective amount of recombinant factor VIII which has been purified according to the present process.

Hemophilia is an inherited disease which has been known for centuries, but it is only within the last four decades that it has been possible to differentiate between the various forms; hemophilia A and hemophilia B. Hemophilia A is the most frequent form. It affects only males with an incidence of one or two individuals per 10 000 live-born males. The disease is caused by strongly decreased level or absence of biologically active coagulation factor VIII (antihemophilic factor), which is a protein normally present in plasma. The clinical manifestation of hemophilia A is a strong bleeding tendency and before treatment with factor VIII concentrates was introduced, the mean age of the patients concerned was less than 20 years. Concentrates of factor VIII obtained from plasma have been available for about three decades. This has improved the situation for treatment of hemophilia patients considerably and offered them the possibility of living a normal life.
Until recently, therapeutic factor VIII concentrates have been prepared by fractionation of plasma. However, there are since some years methods available for production of factor VIII in cell culture using recombinant DNA techniques as reported in e.g. W. Wood et al, Nature, 312, p. 330-37 (1984) and EP-A-0 160 457.
Factor VIII concentrates derived from human plasma contain several fragmented fully active factor VIII forms as described by Andersson et al, Proc. Natl. Acad. Sci. USA, 83, p. 2979-83 (May 1986). The smallest active form has a molecular mass of 170 kDa and consists of two chains of 90 kDa and 80 kDa held together by metal ion(s). Reference is here made to EP-A-0 197 901.
Pharmacia AB of Stockholm, Sweden, has developed a recombinant factor VIII product which corresponds to the 170 kDa plasma factor VIII form in therapeutic factor VIII concentrates. The truncated recombinant factor VIII molecule is termed r-VIII SQ and is produced by Chinese Hamster Ovary (CHO) cells in a cell culture process in serum-free medium.
The structure and biochemistry of recombinant factor VIII products in geneal have been described by Kaufman in Trends in Biotechnology, 9 (1991) and Hematology, 63, p. 155-65 (1991). The structure and biochemistry of r-VIII SQ have been described in WO-A-9109122.
High-performance hydrophobic interaction chromatography (HIC) is a separation technique suitable for purifying proteins. The general characteristics and suitable conditions for carrying out a HIC step have been described by K-O Eriksson in Protein Purification; Principles, High Resolution Methods, and Applications, VCH Publishers, Inc., New York, p. 207-226 (1989). In this technique, proteins are eluted from relatively weak hydrophobic stationary phases using a solution with decreasing ionic strength, introducing a surfactant, changing the polarity of the solvent and/or simply lowering the temperature. Such relatively mild conditions favor the recovery of proteins with essentially retained activity.
The factors affecting adsorption and desorption in HIC are thoroughly reviewed by T. Arakawa and L. Owers Narhi in Biotechnol. Appl. Biochem., 13, p. 151-172 (1991). The influence of surfactants on the interaction of various proteins with a HIC gel (resin) has been described by J. J. Buckley and D. B. Wetlaufer, J. Chrom., 518, p. 99-110 (1990). In this reference, however, the main purpose was to evaluate the influence of the surfactants on the gradient elution profiles.
Various gels (resins) exposing hydrophobic or semihydrophobic ligands have been described, for instance agaroses derivatized with aminoalkyl or diaminoalkyl groups. In the prior art, there are examples of purification of factor VIII by utilizing such gels. For instance, butyl-agarose gel was prepared by derivatizing Sepharose.RTM. 4B (sold by Pharmacia AB of Uppsala, Sweden) with butyl-amine, using CNBr-coupling technique. The resulting gel was utilized for purification of factor VIII, as reported by Th. Vukovich et al in Folia Haematol. Leipzig, 107 (1), p. 148-151 (1979) and Th. Vukovich et al in Haemostasis and Thrombosis (Proc. Serono Symp.), G. G. Neri Semeri and C. R. M. Prentice eds., 15, p. 407-410 (1979). A protein mixture was adsorbed onto this gel at very low ionic strength. Desorption was accomplished by increasing the concentration of sodium chloride. This clearly indicates that the forces utilized were predominantly electrostatic, i.e. mechanisms involved were those normally referred to as ion-exchange chromatography (IEC). Furthermore, it has been reported, for instance by B.-L. Johansson and I. Drevin in J. Chrom., 321, p. 335-342 (1985), that the CNBr-coupling technique creates an iso-urea group between the ligand and the matrix, which is positively charged at acid and neutral pH. This profoundly influences the overall properties of the gel.
Morgenthaler has compared a series of agaroses derivatized with aminoalkyl- or diaminoalkyl groups for purification of factor VIII, as described in Thromb. Haemostas., 47(2), p. 124 (1982). It was found, that it was difficult to attain a reversible binding of factor VIII to the agarose gels derivatized with aminoalkyl groups (alkane Sepharose.RTM.). Thus, salt induced elution was attained only to some extent and only from gels derivatized with short aminoalkyl groups using CNBr-coupling technique. Ethylene glycol elution failed independently of the length of the alkyl chain. In contrast, it has been found, that by addition of detergents at a concentration of .gtoreq.0.1%, desoiption of factor VIII from such columns could be achieved (EP-A-0 209 041). In the examples shown, the capacity of the HIC columns and the concentration of the eluted factor were however low.
EP-A-0 286 323 relates to a two-step procedure for purifying polypeptides, especially factor VIII. The first step uses immobilized antibodies and the second step is based on an affinity region. The affinity region can be an ionic exchange gel or a HIC gel. Detergents are referred to primarily as active agents during the virus inactivation. They are also mentioned, in the prior art, to suppress the intermolecular association mediated by ionic forces, but there is no information about the use of detergents during the adsorption phase on the affinity region.
U.S. Pat. No. 4,743,680 also relates to buffer compositions during purification of factor VIII (anti-hemophilic factor or AHF), by column chromatography. Detergents are mentioned to promote elution from a mixed-function affinity chromatography gel, such as aminohexyl Sepharose.RTM.. There is no information in U.S. Pat. No. 4,743,680 about the use of detergents during the adsorption phase on a hydrophobic resin.
The difficulties met when applying HIC to factor VIII purification, can be attributed to the problems encountered when trying to establish a suitable retention window as well as elution conditions. A suitable retention window means that the factor VIII molecules are retained on the surface of the HIC gel by hydrophobic interaction, while other impurities, mainly nucleic acids and proteins are retained to a lesser degree or, preferably, not at all. A suitable retention window for factor VIII further means, that the factor VIII molecules can be eluted without too severe conditions, thus avoiding denaturation. Such a window can be obtained by selection of a suitable gel consisting of a matrix and hydrophobic ligands attached thereto. The type and density of the ligands strongly influence the interaction between the factor VIII molecules and the surface of the HIC gel, and thereby the retention window. Further parameters influencing the retention window are e.g. the ionic strength, temperature, pH and length of column.
It is of special importance for the selectivity of the process, that such non-specific adsorption factors as positive charges are avoided, since nucleic acids, which are negatively charged, are tolerated at an extremely low level in preparations of therapeutic proteins. Thus, in the purification of therapeutic proteins produced by a recombinant DNA technique, it is well known that considerable problems are encountered when trying to reduce the content of DNA to the very low level stipulated by the Food and Drug Administration (FDA) of the U.S.A recent example is disclosed in P. Ng and G. Mitra of Miles Inc. in the U.S., J. Chrom., A 658, p. 459 (1994), where the concentration of DNA was reduced but only to about 1 ng per dosage of a therapeutic protein as determined by the .sup.32 P R3 DNA hybridization method.
Pure hydrophobic interaction chromatography, using non-charged gels in combination with mild elution conditions, would provide another dimension for purifying recombinant factor VIII, since additional separation criteria would be utilized compared to those already used in ion-exchange and immunoaffinity chromatography. This would increase the number of process techniques available to optimize the overall purification of recombinant factor VIII. Furthermore, it would be valuable to find conditions for a moderately strong adsorption, permitting desorption by mild elution conditions, since a too strong adsorption might change the conformation of the protein.