An apparatus for shipping, storing, and viewing a cornea comprising a container having a viewing window in a container base, an inner sidewall, and a corneal basket arranged within said container base. The corneal basket is in contact with said inner sidewall and adapted to support a corneoscleral disc by including more than one corneal support rod and more than one disc support surface and a lid that sealingly engages with the container.

Each of the applications, patents, and papers cited in this application and in as well as each document or reference cited in each of the applications, patents, and papers (including during the prosecution of each issued patent; "application cited documents"), and each of the PCT and foreign applications or patents corresponding to and/or claiming priority from any of these applications and patents, and each of the documents cited or referenced in each of the application cited documents, are hereby expressly incorporated herein.
The cornea is the transparent structure that forms the anterior one sixth of the outer coat of the eye and is responsible for more than two thirds of its refractive power. The cornea consists of several layers, including the epithelium, stroma, and single-celled endothelium. The endothelium is the most posterior layer, interfacing with the aqueous humor of the anterior chamber of the eye. Corneal clarity is dependent on a relatively dehydrated state. The endothelium plays a key role in maintaining dehydration by both preventing aqueous humor from entering the cornea and by pumping fluid from the corneal stroma into the anterior chamber. Corneal endothelial cells do not replicate. When destroyed by disease or surgery, the remaining cells enlarge and spread out to cover the posterior corneal surface, thus decreasing the cell density (cell count). Corneas with extremely low endothelial cell densities can no longer maintain a dehydrated state. The corneas may decompensate, swell, and become cloudy over time, with an associated loss of visual acuity.
Cornea transplants are used to improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. The most common indication in this category is pseudophakic bullous keratopathy, followed by keratoconus, corneal degeneration, keratoglobus and dystrophy, as well as scarring due to keratitis and trauma. Donor corneas provide the source material for the transplants. Since the health of the cornea at the time of surgery has an impact upon outcomes, it is critical that the cornea container used to store the cornea from the time that it is harvested from the donor eye globe to the point at which it is used in surgery maintains the cornea in an optimal state of health. This need has become even more imperative as LASIK surgery, which renders donor corneas unsuitable for transplant, has become widely accepted in society. Thus, there is a shrinking source of donor corneas and less opportunity to be selective among donated corneas, putting even more importance on the capability of the cornea container to maintain optimal cornea health.
Once removed from the donor, corneas are placed in a cornea container, which is filled with preservation medium and delivered to an eye bank. The eye bank stores the cornea, performs quality assessments by way of slit lamp and specular microscopy, and delivers the cornea to a surgical location. The cornea container should allow the technician that harvests the cornea to easily deposit the cornea into the container, facilitate quality assessments, and make it easy for those performing surgery to easily remove the cornea from the storage container. Unfortunately, cornea containers that are used, or have been conceived, are suboptimal.
The earliest storage containers merely placed the cornea in a vial filled with preservation medium. However, there was no control over the position of the cornea, causing problems that included trapping the endothelium in a position that cut it off from the surrounding medium, allowing the epithelium to make contact with the walls of the vial, letting gas bubbles contact the cornea, and preventing lack of controlled positioning for specular microscopy and slit lamp evaluation. Although it was easy to deposit the cornea into the vial, the ability to easily retrieve the cornea was difficult.
The vial container was improved by attaching the cornea to the lid with a suture in order to allow easier removal of the cornea. But attaching the cornea to the suture required more handling of the cornea by those retrieving them from the donor. It still allowed the endothelium to become trapped in a position that cut it off from the surrounding medium, allowed the epithelium to make contact with the walls of the vial, let gas bubbles contact the cornea, and prevented lack of controlled positioning for specular microscopy and slit lamp evaluation.
In an attempt to overcome some of the problems of attaching a cornea to a suture, U.S. Pat. No. 4,695,536 describes a cornea container that retains the cornea in a fixed position within a medium vial. A steel wire is attached to the lid. An alligator clip is attached to the opposite end of the wire. The person retrieving the cornea attaches the sclera (the tough white opaque tissue that surrounds the cornea) to the alligator clip and carefully attaches the lid so the epithelium comes to reside upon a plurality of dividers that reside in the body of the cornea container. Although this configuration resolves some of the positioning problems of the suture approach, such as preventing the endothelium from being cut off from its media supply, the epithelium is forced to be in direct contact with the dividers that reside in the vial. Direct physical contact between the dividers and the epithelium can cutoff media access, affecting the health of the cells that comprise the epithelium, and can physically damage the epithelium as it is dragged across the dividers when the cornea is removed for surgical implantation. Also, the technician is required to transfer the cornea from forceps to the retaining clip in a manner that prevents damage to the cornea. That process can add contaminants to the container as the technician is likely to place their gloved hands directly upon the alligator clip to open it during the process rather than find a clever way to actuate the alligator clip with a sterile tool. Touching a component that resides within the container, even with gloves, is not good practice because bioburden level is dependent on what the technician's gloves have contacted previously and is also impacted by the skill level of the technician. Thus, the process of using this storage container increases contamination risk and is highly dependent on the skill and patience of the technician. Manipulation of the tissue by the technician may also damage the non-regenerating endothelium. Also, there is no geometry to prevent gas from contacting the cornea as the container is shipped, subjecting the cornea to potential damage in transit.
U.S. Pat. No. 4,844,242 also attempts to prevent the cornea endothelium from becoming trapped face down in a medium vial by orienting the cornea in a fixed position within the retaining lugs of a support ring. However, the harvesting process currently used to obtain donated corneas often leads to corneas of various diameters and rarely results in a completely circular excision. The apparatus '242 does not easily accommodate corneas of various diameters, or those that are not circular, since the support ring and the retaining lugs only allow about a 12% variation in cornea diameter before extra trimming is required. The more the cornea is handled for trimming, the more potential problems arise. For example, twisting, stretching, additional contact with forceps, and extra cutting increase the chances of damage to the tissue, particularly at its edges and on the endothelial cell surface. Furthermore, the outcome can vary from technician to technician since cutting the corneas to match the limited diameters accepted by the apparatus of '242 requires patience, time, and a high level of skill. In general, those obtaining donor corneas desire the least amount of preparation and exposure to the environment necessary before the cornea is placed into its medium storage container. Moreover, the act of using forceps to press the cornea into the retaining lugs of the support ring can inflict further damage to the cornea. Still another problem with the apparatus of '242 is that gas in the container has the potential to make contact with the cornea during shipping, and can even become trapped in direct contact with the endothelium depending on the orientation of the container.
For the reasons described, the US market has avoided the use of the free floating vial, and rejected sutured lids attached to a vial, as well as devices described in patents '536 and '242. Instead, the US standard is a cornea container that allows gravity to position the cornea in a basket that holds the cornea in a fixed location within the container. Throughout, we refer to the cornea container which has come to be the industry standard as a "conventional container". The conventional cornea container includes a corneal basket to hold the cornea. It has completely dominated the US market since at least the late 1980's. The conventional container achieves its popularity because it is so easy to place the cornea into the container's corneal basket and remove it from the container's corneal basket with forceps. Just placing the lid on the container automatically fixes the position of the cornea, the cornea is positioned for examination by slit lamp and specular microscopy, and the process is not highly dependent on the skill level of the technician.
In use, a technician merely drops the cornea, epithelial side down, into the medium filled container. The cornea gravitates to reside upon a corneal basket, formed of a group of prongs emanating from the base of the container that are arranged in a circular pattern. The corneoscleral disc resides upon the prongs in a position such that the plane in which the sclera resides in is generally parallel to the top and the bottom of the container. This allows examination of the cornea by slit lamp and/or specular microscopy. The lid is designed so that a portion of it functions as a viewing window. No matter the orientation of the container, the cornea is kept from falling out of the basket by the viewing window, which is typically only about 0.05 inches from the sclera. A relieved area in the lid acts as a gas trap and occupies the perimeter of the viewing window, controlling the location of gas within the container. A similar gas trap is present in the container. The cornea basket is positioned away from the container walls, allowing gas to move from the lid to the bottom of the container without contacting the corneoscleral disc as the conventional container is inverted.
The conventional cornea container was introduced by Coopervision Inc, Irvine Calif. The basket included eight prongs that rose from the bottom of the container. The corneoscleral disc resided in contact with the prongs. The container left room for improvement however. The basket design included prongs which obstructed the ability for slit lamp observation of the epithelium. Around the late 1980's, Bausch & Lomb entered the market with a conventional cornea container that allowed slit lamp observation. Their product is called the Independent Corneal Viewing Chamber™, and it came to dominate the US market.
Although the conventional cornea container has many advantages over any other proposed or previously tried cornea container, we have discovered that the design acts to limit cornea health. One problem, detailed within, is that the design of the corneal basket impedes the effective use of preservation medium within the container and as a result is suboptimal for maintaining corneal health. The other problem is that the lid design allows the sclera to become suctioned to it, thereby cutting off solute movement to the endothelium, and in some cases, even trapping gas against the endothelium.
A review of conventional container basket geometry helps clarify the problem of effective use of preservation medium within the container. When the cornea resides in the Coopervision cornea container, the prongs only provide a small open area between medium residing within the corneal basket and that outside of the corneal basket. The cross-sectional area of open space (about 0.69 in2) for medium communication is exceeded by that of cross-sectional space occupied by prongs. There is only about 38% of the corneal basket open for preservation medium communication. The distance between prongs is also limited to about 0.1 inch, which acts to trap gas that may form during medium temperature increases as will be explained later. An additional problem exists with the width of the prongs, as measured from the inner diameter to the outer diameter of their basket arrangement. The width of the corneoscleral disc support section is virtually maintained constant from the base of the prong to the point of disc contact (i.e. along the height). That adds further resistance to medium communication. For example, the Coopervision prongs have a width of about 0.4 inches.
The same problems exist in Bausch & Lomb's Independent Corneal Viewing Chamber™, which will be detailed further within.

Cornea storage container to maximize cornea health


An electrolytic capacitor includes an anode lead, a cathode lead and a seat plate. The seat plate has two grooves. The anode lead is bent along one of the grooves in the seat plate to be placed in the groove. The cathode lead is bent along the other groove in the seat plate to be placed in the groove. Accordingly, a space will be formed between the anode lead and the edges of one of the grooves in the seat plate, and likewise, between the cathode lead and the edges of the other groove in the seat plate. The anode lead and the cathode lead are mounted to a substrate with solders, and the electrolytic capacitor is mounted to the substrate. Accordingly, enhanced adhesion of the electrolytic capacitor to substrates is achieved.

1. Field of the Invention
The present invention relates to winding type electrolytic capacitors.
2. Related Art
Following the recent demand for electrical circuits that are smaller in size and adapted for high-frequency, capacitors with lower impedance have been required. In particular, absorption of high-frequency noise and ripple current is required in designing driving circuits for CPUs (Central Processing Units) of computers, switching power circuits and the like, and therefore, capacitors with low ESR (Equivalent Series Resistance) have become necessary.
Winding type electrolytic capacitors have been attracting attention as their ESR can be made lower. Japanese Patent No. 2606297 discloses a well-known electrolytic capacitor with high capacitance. This electrolytic capacitor includes an anode foil, a cathode foil and a separator sheet placed therebetween, which are rolled up together.


A cyclone dust-collecting apparatus and a vacuum cleaner having the same are provided. The cyclone dust-collecting apparatus including: a cyclone body having a suction part through which air is drawn in and a discharge part through which the air is discharged; a grill connected to the discharge part, for filtering the air; a dirt receptacle connected to the cyclone body, for collecting dirt separated from the air which is drawn in through the suction part; and a downstream guide part for preventing dirt collected in the dirt receptacle from being scattered, and, of the dirt included in the drawn-in air, downward guiding a dirt having at least one of a predetermined weight and a predetermined size in a spiral direction by a flux of the air to the dirt receptacle.

1. Field of the Invention
The present invention relates to a vacuum cleaner, and more particularly, to a cyclone dust-collecting apparatus and a vacuum cleaner having the same.
2. Description of the Related Art
In general, a cyclone dust-collecting apparatus is used in a bag-less vacuum cleaner to draw in dirt-laden air, generate a whirling current in the dirt-laden air to separate the dirt from the air using a centrifugal force generated by the whirling current.
FIG. 1 is a view schematically illustrating a conventional cyclone dust-collecting apparatus applied to a vacuum cleaner.
As shown in FIG. 1, the cyclone dust-collecting apparatus 1 comprises a cyclone separator or cyclone body 10, a suction part 11 for drawing in air therethrough, a discharge part 12 for discharging dirt-removed air therethrough, a grill 13 connected to the discharge part 12, and a dirt receptacle 14 for collecting and storing dirt therein.
Operation of the cyclone dust-collecting apparatus 1 is as follows.
Dirt-laden air is drawn in from a cleaning surface by a vacuum motor (not shown) of the vacuum cleaner and guided to the cyclone body 10 through the suction part 11.
Since the suction part 11 is connected tangentially to an inner circumference of the cyclone body 10, the air guided to the cyclone body 10 whirls along the inner circumference of the cyclone body 10 in the arrow direction as shown in FIG. 2 so that dirt is centrifugally separated from the air.
The dirt centrifugally separated from the air by the whirling current is guided by the inner circumference of the cyclone body 10 and falls down to the dirt receptacle 14 via a communication space 15 disposed between the cyclone body 10 and the dirt receptacle 14 by the whirling current and gravity.
Air having the dirt removed therefrom is filtered through perforations 16 of the grill 13 connected to the discharge part 12 and discharged from the cyclone dust-collecting apparatus 1 through the discharge part 12.
The cyclone dust-collecting apparatus 1 has a circular flange 17 formed under the grill 13 to prevent the dirt collected in the dirt receptacle 14 from being scattered by the whirling current and sucked into the grill 13 through the perforations 16.
If the air drawn in through the suction part 11 includes a heavy dirt item having a predetermined weight such as a coin or a bottle cap, the heavy dirt item does not directly fall down to the dirt receptacle 14 via the communication space 15 and rotates together with the whirling current onto the flange 17. As a result, the heavy dirt item is brought into contact with the flange 17, which causes an objectionable noise.
If a dirt mass having a predetermined size such as a dust ball or a dust hair is formed while the air whirls along the inner circumference of the cyclone body 10, the dirt mass is too big to directly fall down to the dirt receptacle 14 via the communication space 15, and thus rotates together with the whirling current onto the flange 17. At this time, microscopic particulates of dust are scattered from the dirt mass when the dirt mass collides the flange 17, and go back to the whirling current along the inner circumference of the cyclone body 10. Consequently, the microscopic particulates of dust may be discharged from the cyclone dust-collecting apparatus 1 to the outside through the perforations 16 of the grill 13, which causes a deterioration of the dust-collection efficiency of the dust-collecting apparatus 1.
In order to solve the above problems, another conventional cyclone dust-collecting apparatus 1′ as shown in FIG. 3 is suggested. The cyclone dust-collecting apparatus 1′ has a cut-off part 19 formed in a flange 17′. This cyclone dust-collecting apparatus 1′ is advantages in that the heavy dirt item or the dirt mass is collected in the dirt receptacle 14 rapidly. However, it cannot completely solve the problems of the noise and the deterioration of the dust-collection efficiency. More specifically, since the flange 17′ having the cut-off part 19 has a plane structure and the heavy dirt item or the dirt mass has an inertia that continues rotating, even if it has a predetermined weight or a predetermined size, it falls down to the dirt receptacle 14 through the cut-off part 19 after jumping over the cut-off part 19 and rotating around the flange 17′ one or two times. As a result, the heavy dirt item or the dirt mass is brought into contact with the flange 17′ until it falls down to the dirt receptacle 14 through the cut-off part 19, which causes a noise or microscopic particulates of dust to be scattered.

Cyclone dust-collecting apparatus and a vacuum cleaner having the same


A data storage method and a data storage apparatus are provided. The method includes determining a type of operating system of a host. A configuration file corresponding to the type of the operating system is stored in a data card connected to the host. A memory file system is established according to a first mounting information in the configuration file. A storage device is mounted according to a second mounting information in the configuration file. A correspondence between a storage space in the memory file system and the mounted storage device is set. The mounted storage device is used to store data that is to be stored in the data card.

A data card is a device that provides an additional application function and is applied to a portable device such as a portable computer, for example, a mobile data card is a device that enables, through a mobile communications technology, a portable device to access a mobile network. During working, a data card that is connected to a portable device through a universal serial bus (USB) interface is referred to as USB data card.
As mobile applications rapidly become various and people have an increasingly growing requirement for network access convenience, the number of data card users rapidly increases. Users expect that a data card can carry more data to support various application programs, and mobile service operators and data card providers also expect to provide more various and more complicate applications for the users through the data card. However, due to a restriction of a manufacturing skill of the data card, storage capacity and interface input/output (I/O) performance of the data card cannot meet the requirement currently. By taking a USB interface on a USB data card as an example, in the aspect of I/O performance, there is a large gap between the USB interface and another interface, such as an integrated-drive-electronics (IDE) interface or a serial advanced technology attachment (SATA) interface, used in a host or a large-capacity storage.
In a process of implementing the present invention, the inventor finds that, except that an improvement is made to a manufacturing skill of a data card, the prior art fails to provide a solution that can effectively solve a problem of a restriction of storage capacity of the data card.

Data storage method and data storage apparatus


A sight module includes a mounting base for detachably mounting on a firearm, a sight unit including a sight housing upwardly extended from the mounting base, a reflex sight including a light unit supported by the sight housing for generating a sight reticle, and a foldable lens movably coupled at the sight housing and being actuated to move between a first position and a second position. In the first position, the foldable lens is folded at the sight housing. In the second position, the foldable lens is moved to outwardly extend from the sight housing, such that the sight reticle generated by the reflex sight is projected on the foldable lens in the second position.

1. Field of Invention
The present invention relates to a sight device, and more particular to a sight module, which integrates a sight device with a reflex sight for facilitating an operator to aim a target in different environments.
2. Description of Related Arts
Conventional firearm, such as a gun or a rifle, usually needs different firearm accessories for assisting the operator to accurately locate the target and perform the shooting. Sighting device, such as a scope, reflex sight, telescope, camera lens module, or binoculars, generally comprises a tubular lens housing and a lens supported in the lens housing. For example, scopes are sighting device and are commonly used in conjunction firearms, such as rifles, to give an accurate aiming point and to aid the operator in properly aligning a barrel of the firearm with a desired target. Accordingly, two lenses are provided at two ends of the lens housing to define an objective end and a sight (ocular) end. The scope further comprises a scope luminous element which is powered by a battery and is operatively provided in the lens housing for illumining a scope reticle thereof.
Accordingly, magnified or powered scopes are used for mid to long range sniping to aim and identify targets at further distances. The magnified scope generally comprises windage and elevation knobs to change an apparent reticle position of the scope. In particular, the windage knob is used to adjust the scope in the horizontal axis and the elevation knob is used to adjust the scope in the vertical axis. The calibration of the apparent reticle position is incorporate with the bore of the barrel of the firearm according to the hand-eye position of the user in order to allow the user to precisely aim and shoot the target.
Reflex sight device is another type of scope device which is better suited for quick target acquisition and is easier for tracking moving targets at closer ranges comparing with the magnified scope. Reflex sight generally comprises a lens with a luminous to create an optical collimator so as to produce a virtual image of the reticle. A control switch is provided for controlling the reticle illumination level and dot brightness level of the reflex sight.
The magnified scope and reflex sight are perfect companion for the user to aim and identify targets at different distances. The user can switch between these two scope devices especially for a moving target. However, the magnified scope and reflex sight must be individually mounted at different locations of the firearm. In other words, the two individual scope devices will also take up limited mounting space of the firearm, such that other firearm accessories, such as laser sight, navigation lights, flashlight, or a camera, will not be able to attach to the firearm. In addition, since each scope device employs its own power source for reticle illumination. As a result, the overall weight of the scope devices will be substantially increased to apply additional weight on the firearm. More importantly, the magnified scope and reflex sight have their sizes, such that when the magnified scope and reflex sight are individually mounted on the firearm, the overall size of the firearm will bulky.


A polymer high voltage current limiter comprising, per phase, a fast circuit-breaker pole, a semi-fast protection circuit-breaker pole, and a set of polymer-based elements having very low resistivity, filled with carbon black, and connected in series and in parallel, wherein each element comprises a carbon-filled polymer matrix of elongate shape and including in its interior two parallel metal conductors.

In French patent application No. 95/10662 of Sep. 12, 1995, the Applicant describes a polymer current limiter comprising at least one stack of a plurality of stages of linear resistance elements and of polymer variable resistance elements, wherein each stage is constituted by a linear resistance in the form of a disk around which there are connected in parallel pellet-form polymer elements, the transverse axes of said pellets being perpendicular to the axis of the stack.
The polymer elements are small in size and above all small in thickness, and they possess metal tabs soldered to each face thereof with the ends thereof being soldered to a current collector.
That device, which requires a large number of solder joints or electrical connections, is expensive and it is not sufficiently robust.
Also, each element has its own relatively high capacitance. This gives rise to a large amount of capacitance per stage, which means that it is possible to unbalance the distribution of voltage between stages.

Polymer high voltage current limiters packaged in series


In a technique for bonding two disc-shaped resin substrates constituting the storage disc, the disc-shaped resin substrates are centered to correct the nonalignment therebetween. The method includes steps of placing disc-shaped resin substrates, which have central holes and adhesive interposed therebetween, on a centering holding table provided with a boss, spreading the boss inserted into the central holes of the disc-shaped resin substrates outwardly to center the disc-shaped resin substrates, and partially irradiating the adhesive interposed between the disc-shaped resin substrates with UV rays for curing the disc-shaped resin substrates in the vicinity of the centers thereof to temporarily fix the disc-shaped resin substrates. The nonalignment between the disc-shaped resin substrates is corrected, thereby increasing the quality of the storage disc. Further, the boss inserted into the central hole of the storage disc is used to center the disc-shaped resin substrates, which prevents the apparatus from being complex and expensive to manufacture.

1. Field of the Invention
The present invention relates to a storage disc, particularly to a method of correcting nonalignment between disc-shaped resin substrates each constituting a storage disc.
2. Prior Art
Computers, especially personal computers, have become remarkably popular recently, and the capacity of the storage medium to be used thereby, particularly the capacity of a storage disc and the kinds of storage media have increased. In addition, the application of storage discs to various fields has also increased. Accordingly, in a CD mainly for use in music, there is a tendency to develop the storage disc as a video disc.
The storage disc may be in the form of a magnetic disc, an optical disc (e.g., CD-ROM), an optical magnetic disc (e.g., MO), etc. The demand for optical discs as storage, discs has increased recently.
Exemplifying an optical disc called a DVD, a disc-shaped resin substrate that is a single plate constituting the DVD is required to have a thickness of 0.6 mm, an outer diameter of 120 mm, and a central hole inner diameter of 15 mm. If such a disc-shaped resin substrate is formed of a single substrate, it is low in a mechanical strength and is easily deformable. Accordingly, two disc-shaped resin substrates each having the same thickness (0.6 mm) are bonded to each other to form an integrated substrate.
For example, FIGS. 11(A) and (B) schematically generally show a DVD serving as an optical disc which DVD is formed of two disc-shaped resin substrates (a first disc-shaped resin substrate D1 and a second disc-shaped resin substrate D2) which are bonded to each other.
An Information signal is applied to one disc-shaped resin substrate D1, namely information is stored in one disc-shaped resin substrate as shown in FIG. 11(A), while information is stored in both disc-shaped substrates D1 and D2 as shown in FIG. 11(B).
An optical disc D formed by bonding two disc-shaped resin substrates D1 and D2 receives light reflected from the reflection film D11 using a laser beam by a light detector, not shown, to thereby reproduce signals.
Since the high density storage disc including the DVD does not include a single substrate or plate, but frequently includes plural substrates or plates, the first disc-shaped resin substrate D1 and the second disc-shaped resin substrate D2 must be bonded to each other.
The following series of steps are performed to form an integrated storage disc (i.e., an optical disc) by bonding each single plate (see FIG. 12).
Step 1: placing the first disc-shaped resin substrate D1 on a rotary holding table C;
Step 2: coating an adhesive R onto the first disc-shaped resin substrate D1;
Step 3: placing the second disc-shaped resin substrate D2 on the first disc-shaped resin substrate D1;
Step 4: developing the adhesive R interposed between the first and second disc-shaped resin substrates D1 and D2; and
Step 5: curing the thus developed adhesive R.
These steps are explained in more detail herebelow.
In Step 1, the first disc-shaped resin substrate D1 having thereon an information storage surface coated with a reflection film and a protection film is uniformly drawn by and held on the rotary holding table C.
In Step 2, the adhesive R, e.g., UV curing resin is slowly discharged from a discharge nozzle N while the rotary holding table C on which the first disc-shaped resin substrate D1 is placed is rotated at low speed (several ten rpm). The adhesive R has a different track on the first disc-shaped resin substrate D1 depending on a manner in which it is discharged from the discharge nozzle N, but it is preferable to have a doughnut-shaped track as shown in FIGS. 11(A) and 11(B).
In Step 3, a transparent second disc-shaped resin substrate D2 is placed on the first disc-shaped resin substrate D1 which is coated with the adhesive R. The substrate D2 may be in the form of a transparent substrate on which no information signal is applied, or the substrate D2 may be in the form of a substrate on which an information signal is applied.
In Step 4, the adhesive R interposed between the first and second disc-shaped resin substrates D1 and D2 is developed to extend uniformly between the first and second disc-shaped resin substrates D1 and D2.
This development of the adhesive R is performed by rotating the rotary holding table C at high speed (normally, several thousands rpm or more for about several seconds) in a state where the storage disc D, namely, the integrated disc-shaped resin substrate formed by bonding the first and second disc-shaped resin substrates D1 and D2, is placed on the rotary holding table C.
When the rotary holding table C is rotated at high speed, surplus adhesive R which is present between the bonded first and second disc-shaped resin substrates D1 and D2 is scattered outside while it is developed, and air (air bubble, etc.) confined between the first and second disc-shaped resin substrates D1 and D2 is discharged outside so that the adhesive R can be uniformly developed between the first and second disc-shaped resin substrates D1 and D2. During the development of the adhesive R, the adhesive R is drawn in the direction of the center through the boss of the rotary holding table which is inserted into the central hole of the storage disc.
In Step 5, the optical disc is irradiated with UV rays, namely, after the first and second disc-shaped resin substrates D1 and D2 are irradiated with UV rays in a state where the optical disc is slowly rotated (e.g. at about several rpm which is much slower than the rpm in the developing state set forth above) or not rotated so that the adhesive R, e.g., a UV curing resin layer is cured.
More specifically, the adhesive R is irradiated with UV light source UL provided with a reflection mirror at the back side thereof, thereby effectively curing the adhesive.
Further, the curing step is differs due to the kind of the adhesive R to be used, and hence it should be understood that a curing method conforming to the characteristic of the adhesive to be used is employed. In such a manner, the bonding step is completed.
In disc-shaped resin substrates of the type used to store information, such as substrates D1 and D2, there are two methods used to obtain information from the storage disc. The first method includes reading the information or signal by applying light from one direction (a method of reading information from a storage disc of a type having a standard used by a dual layer DVD), and the second method includes reading information by applying light from both directions (a method of reading information from a storage disc used by a single layer or double-sided DVD). In the first method, if there is a misalignment between the disc-shaped resin substrates D1 and D2, information contained in the disc-shaped resin substrates D1 and D2 cannot be correctly read if the central holes of the substrates are not concentrically positioned.
FIG. 10 shows a state where the nonalignment occurs between the disc-shaped resin substrates D1 and D2 and wherein slippage of information stored in the disc-shaped resin substrates D1 and D2 also occurs. If the disc-shaped resin substrates D1 and D2 are bonded with each other in this state, the information cannot be correctly read from one direction.
Meanwhile, in a standard of dual layer DVD, it is preferable that the nonalignment between the disc-shaped resin substrates D1 and D2 does not exceed 15 .mu.m to prevent the DVD from becoming a defective product. The nonalignment has already occurred in a state where the disc-shaped resin substrate D2 is placed on the disc-shaped resin substrate D1.
In the next developing step, the adhesive is developed on the rotary holding table on which the disc-shaped resin substrates D1 and D2 are placed while there occurs the nonalignment or misalignment therebetween.
In the developing step, the boss 1 on the rotary holding table is inserted into the central holes of the disc-shaped resin substrates D1 and D2 to temporarily position the disc-shaped resin substrates D1 and D2. Since there is a slight difference between the outer diameter of the boss 1 and the diameters of the central holes of the disc-shaped resin substrates D1 and D2, a minute nonalignment between the disc-shaped resin substrates D1 and D2 cannot be corrected even when they are positioned by the boss 1.
Accordingly, the nonalignment between the disc-shaped resin substrates D1 and D2 is not corrected but remains as it is, even if the developing step of the adhesive is completed.
Although the adhesive is cured on the entire surfaces on the disc-shaped resin substrates D1 and D2 in the curing step upon completion of the developing step, the nonalignment remains as it is, namely, it is fixed when the adhesive is cured, which permits the nonalignment to remain on the final product.
Under the circumstances, it is necessary that the nonalignment between the disc-shaped resin substrates D1 and D2 must be removed or corrected to the utmost before the curing step occurs.

Method of correcting nonalignment of a storage disc


A padlock includes a housing, a shackle, a number lock mechanism, a key lock mechanism, a movable block, and an identification member. Thus, the identification member is exposed outward from the window of the limit knob after the padlock has been unlocked by an inspector of the customs for checking the luggage so as to remind a user to inspect if contents of the luggage that has been opened and checked are missed or lost.

1. Field of the Invention
The present invention relates to a padlock, and more particularly to a padlock having an identification function so as to remind a user to inspect the luggage.
2. Description of the Related Art
A conventional dual lock in accordance with the prior art was disclosed in the Taiwanese Patent Publication No. 590146 and comprises a housing, a shackle mounted on the housing, a first locking mechanism mounted on the housing to lock and unlock the shackle, and a second locking mechanism mounted on the housing to lock and unlock the shackle. The first locking mechanism can be opened by the user only, and the second locking mechanism can be opened by a specified key. The specified key is often held by an inspector of the customs, so that the inspector can directly unlock the second locking mechanism of the padlock by the specified key so as to open and check a luggage locked by the padlock without having to break the padlock for checking the luggage. Then, the inspector can lock the second locking mechanism of the padlock by the specified key so as to lock the luggage by the padlock again. However, the user cannot directly judge if the padlock has been unlocked by the inspector for opening and checking the luggage, so that the user has to unlock multiple padlocks to inspect each piece of luggage so as to judge if the luggage has been opened and checked, thereby causing inconvenience to the user.

Padlock having an identification function


The present invention is a method and an apparatus to use carrierless signals for energizing remote passive or active transponders (tags) and for communication link between a reader and the transponders. The reader's transceiver generates very short high power pulses to transmit them to the transponder which receives and stores the pulse energy in an energy store on the transponder. At the transponder the power pulse signal is compressed by a matched filter and rectified. Information to be transmitted from the reader to the transponder and from the transponder to the reader can be added to the data pulses by means of pulse position modulation, bi-phase modulation or other well-known wide-band modulation techniques. The communication is active as the transponder utilizes stored power for transmission and reception of signals while the transponder can be passive and is powered by the reader's signal energy.

RFID technology is one of many identification technologies in the automatic data identification industry. RFID market is growing sector of the radio technology industry, which brings together elements from many varied fields such as RF/microwave technology, semiconductor technology, telecommunications, data protection and cryptography, manufacturing technology, IT and many related areas.
Generally speaking a RFID system consists of two components, namely the transponder or tag, which is located on the object to be identified and the interrogator or reader, which may be a read or read/write device.
The heart of the RFID system lies in the transponder that carries information. The transponder responses to a coded RF signal received from the reader. Low cost and small size transponders are of most intense commercial interest. So-called passive transponder does not possess its own voltage supply. It is activated and functions when it is within the interrogation zone of the reader. As a passive transponder does not require a battery the cost of such transponder is usually low. However, a disadvantage of passive transponders is a short range.
The passive RFID transponder derives its energy (using an integrated rectifier) from the RF continuous wave interrogating signal and transmits the data by modulation of reflection cross-section (backscatter modulation).
Using current low power semiconductor technology, transponder chips can be produced with a power consumption of less than 5 μW. An efficiency of an integrated rectifier can be assumed to be 5-15% in UHF/microwave band. Therefore, an average received power of 50 μW is required at the terminal of the tag antenna for operation of the tag chip. In such a case, sufficiently high reader's transmitter power is required for the operation of the transponder chip.
In order to utilize the received power as effectively as possible, power matching should be provided. In case power matching is not provided, only part of the power is available to the rectifier (Schottky detector). Moreover, one should take into account the tag antenna matching losses including the fact that during altering the load (backscatter modulation) tag impedance is always changed. Thus, only a small proportion of incoming power is effective and circuit efficiency of the tag thereby is very low.
To send data from the transponder to the reader the input impedance of the transponder is altered in time with the data to be transmitted by the switching on and off additional impedance in time with the data to be transmitted. As a result, the power reflected by the transponder is modulated in time with the data. This procedure is known as modulated backscatter. Alternating the input impedance of the transponder results in the amplitude and/or phase modulation.
During backscatter the reader has permanently switched the transmitter on. Therefore, the sensitivity of the receiver in the reader is drastically reduced. In fact, for the transponder to be detected, the transponder's signal should be not more than 100 dB below the reader's carrier signal. The signal reflected by the transponder is modulated. In ASK (Amplitude Shift Keying) with a modulation index 100% the two sidebands would each contain 25% of the total reflected power, and in practice respectively less at a lower modulation index. As a result, it is difficult to achieve long operational distance between transponder and reader in passive transponder.
As is evident from what is said above, there are serious draw backs in the currently known systems. Hence, there is a clear need for a RFID system that could have long range of operation, low sensitivity to electromagnetic interference fields, high data security, high data rate, low cost, fast operation, and mobility.
The instant disclosure introduces solutions to the drawback of the currently known systems and provides a carrierless RFID system that possesses long range of operation, low sensitivity to electromagnetic interference fields, high data security, high data rate, low cost, fast operation, and mobility.


A system for non-invasively measuring an analyte in a vehicle driver and controlling a vehicle based on a measurement of the analyte. At least one solid-state light source is configured to emit different wavelengths of light. A sample device is configured to introduce the light emitted by the at least one solid-state light source into tissue of the vehicle driver. One or more optical detectors are configured to detect a portion of the light that is not absorbed by the tissue of the vehicle driver. A controller is configured to calculate a measurement of the analyte in the tissue of the vehicle driver based on the light detected by the one or more optical detectors, determine whether the measurement of the analyte in the tissue of the vehicle driver exceeds a pre-determined value, and provide a signal to a device configured to control the vehicle.

The present application generally relates to a system and methods for non-invasively measuring an analyte in a vehicle driver. More specifically, the application relates to a measurement quantitative spectroscopy system for measuring the presence or concentration of an analyte, for example, alcohol, alcohol byproducts, alcohol adducts, or substances of abuse, utilizing non-invasive techniques in combination with multivariate analysis.
Current practice for alcohol measurements is based upon either blood measurements or breath testing. Blood measurements define the gold standard for determining alcohol intoxication levels. However, blood measurements require either a venous or capillary sample and involve significant handling precautions in order to minimize health risks. Once extracted, the blood sample must be properly labeled and transported to a clinical laboratory or other suitable location where a clinical gas chromatograph is typically used to measure the blood alcohol level. Due to the invasiveness of the procedure and the amount of sample handling involved, blood alcohol measurements are usually limited to critical situations such as for traffic accidents, violations where the suspect requests this type of test, and accidents where injuries are involved.
Because it is less invasive, breath testing is more commonly encountered in the field. In breath testing, the subject must expire air into the instrument for a sufficient time and volume to achieve a stable breath flow that originates from the alveoli deep within the lungs. The device then measures the alcohol content in the air, which is related to blood alcohol through a breath-blood partition coefficient. The blood-breath partition coefficient used in the United States is 2100 (implied units of mg EtOH/dL blood per mg EtOH/dL air) and varies between 1900 and 2400 in other nations. The variability in the partition coefficient is due to the fact that it is highly subject dependent. In other words, each subject will have a partition coefficient in the 1900 to 2400 range that depends on his or her physiology. Since knowledge of each subject's partition coefficient is unavailable in field applications, each nation assumes a single partition coefficient value that is globally applied to all measurements. In the U.S., defendants in DUI cases often use the globally applied partition coefficient as an argument to impede prosecution.
Breath measurements have additional limitations. First, the presence of "mouth alcohol" can falsely elevate the breath alcohol measurement. This necessitates a 15-minute waiting period prior to making a measurement in order to ensure that no mouth alcohol is present. For a similar reason, a 15 minute delay is required for individuals who are observed to burp or vomit. A delay of 10 minutes or more is often required between breath measurements to allow the instrument to return to equilibrium with the ambient air and zero alcohol levels. In addition, the accuracy of breath alcohol measurements is sensitive to numerous physiological and environmental factors.
Multiple government agencies, and society in general, seek non-invasive alternatives to blood and breath alcohol measurements. Quantitative spectroscopy offers the potential for a completely non-invasive alcohol measurement that is not sensitive to the limitations of the current measurement methodologies. While non-invasive determination of biological attributes by quantitative spectroscopy has been found to be highly desirable, it has been very difficult to accomplish. Attributes of interest include, as examples, analyte presence, analyte concentration (e.g., alcohol concentration), direction of change of an analyte concentration, rate of change of an analyte concentration, disease presence (e.g., alcoholism), disease state, and combinations and subsets thereof. Non-invasive measurements via quantitative spectroscopy are desirable because they are painless, do not require a fluid draw from the body, carry little risk of contamination or infection, do not generate any hazardous waste, and can have short measurement times.
Several systems have been proposed for the non-invasive determination of attributes of biological tissue. These systems have included technologies incorporating polarimetry, mid-infrared spectroscopy, Raman spectroscopy, Kromoscopy, fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, radio-frequency spectroscopy, ultrasound, transdermal measurements, photo-acoustic spectroscopy, and near-infrared spectroscopy. However, these systems have not replaced direct and invasive measurements.
As an example, Robinson et al. in U.S. Pat. No. 4,975,581 disclose a method and apparatus for measuring a characteristic of unknown value in a biological sample using infrared spectroscopy in conjunction with a multivariate model that is empirically derived from a set of spectra of biological samples of known characteristic values. The above-mentioned characteristic is generally the concentration of an analyte, such as alcohol, but also can be any chemical or physical property of the sample. The method of Robinson et al. involves a two-step process that includes both calibration and prediction steps.
In the calibration step, the infrared light is coupled to calibration samples of known characteristic values so that there is attenuation of at least several wavelengths of the infrared radiation as a function of the various components and analytes comprising the sample with known characteristic value. The infrared light is coupled to the sample by passing the light through the sample or by reflecting the light off the sample. Absorption of the infrared light by the sample causes intensity variations of the light that are a function of the wavelength of the light. The resulting intensity variations at a minimum of several wavelengths are measured for the set of calibration samples of known characteristic values. Original or transformed intensity variations are then empirically related to the known characteristics of the calibration samples using multivariate algorithms to obtain a multivariate calibration model. The model preferably accounts for subject variability, instrument variability, and environment variability.
In the prediction step, the infrared light is coupled to a sample of unknown characteristic value, and a multivariate calibration model is applied to the original or transformed intensity variations of the appropriate wavelengths of light measured from this unknown sample. The result of the prediction step is the estimated value of the characteristic of the unknown sample. The disclosure of Robinson et al. is incorporated herein by reference.
A further method of building a calibration model and using such model for prediction of analytes and/or attributes of tissue is disclosed in commonly assigned U.S. Pat. No. 6,157,041 to Thomas et al., entitled "Method and Apparatus for Tailoring Spectrographic Calibration Models," the disclosure of which is incorporated herein by reference.
In U.S. Pat. No. 5,830,112, Robinson describes a general method of robust sampling of tissue for non-invasive analyte measurement. The sampling method utilizes a tissue-sampling accessory that is pathlength optimized by spectral region for measuring an analyte such as alcohol. The patent discloses several types of spectrometers for measuring the spectrum of the tissue from 400 to 2500 nm, including acousto-optical tunable filters, discrete wavelength spectrometers, filters, grating spectrometers and FTIR spectrometers. The disclosure of Robinson is incorporated herein by reference.
Although there has been substantial work conducted in attempting to produce commercially viable non-invasive near-infrared spectroscopy-based systems for determination of biological attributes, no such device is presently available. It is believed that prior art systems discussed above have failed for one or more reasons to fully meet the challenges imposed by the spectral characteristics of tissue which make the design of a non-invasive measurement system a formidable task. Thus, there is a substantial need for a commercially viable device which incorporates subsystems and methods with sufficient accuracy and precision to make clinically relevant determinations of biological attributes in human tissue.

This patent is subject to a terminal disclaimer.

System for non-invasive measurement of an analyte in a vehicle driver

Automotive Coalition For Traffic Safety, Inc.


A cobalt- or ruthenium-containing hydrocarbon synthesis catalyst, subjected to short term, reversible, partial deactivation in a slurry synthesis process can be rejuvenated, i.e., at least about 80+% catalyst activity recovery, by treating the catalyst in the presence of liquid hydrocarbons, preferably the slurry hydrocarbons, with hydrogen at elevated temperatures and pressures.

During hydrocarbon synthesis the conversion of CO decreased with time. This may be due to the deactivation of the catalyst or slurry liquid properties charging limiting mass transfer. Nevertheless, the mode of deactivation of hydrocarbon synthesis catalysts is not too well understood, but is believed to be related, at least somewhat, to the mode in which the hydrocarbon synthesis is carried out; e.g., a different deactivation mode is likely present for catalyst in fixed bed operations than the deactivation mode for slurry phase operations. Thus, fixed bed processes are essentially plug flow operations involving reactant gradients as they progress through the catalyst bed whereas slurry phase operations involve sufficient backmixing tending towards a more uniform distribution of reactants and products throughout the slurry phase. For example, in a fixed bed water would not be present at the start of the reaction and would build up as the reaction progressed through the bed. However, in a slurry phase, e.g., in a slurry bubble column, because of back mixing effects, water will be present throughout the reaction slurry bed. Consequently, deactivation modes, dependent to any degree on the presence of water, will be different for fixed bed and slurry phase processes.
Hydrogen rejuvenation treatments have been employed with catalysts operated in fixed beds with, at best, limited and inconsistent recovery of hydrocarbon synthesis activity. In one case, steady state operation in the fixed bed had not been achieved, in other cases excessively high temperatures were employed, and still in other cases the hydrogen treatment was in the absence or substantial absence of hydrocarbon liquids.

Rejuvenation of hydrocarbon synthesis catalyst


A tomography apparatus includes a data acquirer which acquires a first image which corresponds to a first time point and a second image which corresponds to a second time point by performing a tomography scan on an object; an image reconstructor which acquires first information which relates to a relationship between a motion amount of the object and the time based on a motion amount between the first image and the second image, predicts a third image which corresponds to a third time point between the first and second time points based on the first information, corrects the first information by using the predicted third image and measured data which corresponds to the third time point, and reconstructs the third image by using the corrected first information; and a display which displays the reconstructed third image.

1. Field
One or more exemplary embodiments relate to a tomography apparatus and a method for reconstructing a tomography image by the tomography apparatus.
More specifically, one or more exemplary embodiments relate to a tomography apparatus that constructs a tomography image by performing a tomography scan on a moving object, and a method for reconstructing a tomography image which is performable by the tomography apparatus.
2. Description of the Related Art
Medical imaging apparatuses are equipment configured for acquiring an internal structure of an object as an image. Medical image processing apparatuses are noninvasive examination apparatuses that capture images of the structural details of a human body, internal tissue thereof, and fluid flow within a human body, process the images, and show the processed images. A user such as a doctor may diagnose a health state and a disease of a patient by using a medical image output from a medical image processing apparatus.
Representative examples of apparatuses for radiating X-rays onto a patient to scan an object include tomography apparatuses. Examples of the tomography apparatuses include a computed tomography (CT) apparatus.
Among medical image processing apparatuses, CT apparatuses are capable of providing a cross-sectional image of an object and distinctively expressing inner structures (e.g., organs such as a kidney, a lung, etc.) of the object, as compared with general X-ray apparatuses. Thus, CT apparatuses are widely used for accurately diagnosing a disease. Hereinafter, a medical image acquired by a tomography apparatus is referred to as a tomography image. In detail, a medical image acquired by a CT apparatus is referred to as a CT image.
To acquire a tomography image, a tomography scan is performed on an object using a tomography apparatus, and thus raw data is acquired. The tomography image is reconstructed using the acquired raw data. The raw data may be projection data acquired by projecting X-rays to the object, or a sinogram that is a collection of pieces of the projection data.
For example, in order to acquire a CT image, image reconstruction should be performed using a sinogram acquired by a CT scan. Reconstruction of a CT image will now be described in detail with reference to FIG. 1.
FIGS. 1A and 1B are a schematic diagram and images which illustrate a CT scan and reconstruction of a CT image, respectively.
In detail, FIG. 1A is a schematic diagram which illustrates a CT scan that is performed by a CT apparatus that performs a CT scan while rotating around an object 25 and acquires raw data which corresponds to the CT scan. FIG. 1B illustrates a sinogram acquired by a CT scan and a reconstructed CT image.
The CT apparatus generates X-rays, radiates the X-rays toward the object 25, and detects X-rays that have passed through the object 25 by using an X-ray detector (not shown). The X-ray detector produces raw data which corresponds to the detected X-rays.
In detail, referring to FIG. 1A, an X-ray generator 20 included in the CT apparatus radiates X-rays toward the object 25. When the CT apparatus performs a CT scan, the X-ray generator 20 rotates around the object 25 and acquires a plurality of pieces of raw data, for example, first raw data 30, second raw data 31, and third raw data 32, corresponding to angles to which the X-ray generator 20 rotates, respectively. In detail, the X-ray detector (not shown) detects X-rays applied to the object 25 at a position P1 to thereby acquire the first raw data 30, and detects X-rays applied to the object 25 at a position P2 to thereby acquire the second raw data 31. The X-ray detector (not shown) detects X-rays applied to the object 25 at a position P3 to thereby acquire the third raw data 32. The raw data may include projection data.
In order to generate one cross-sectional CT image, the X-ray generator 20 should perform a CT scan while rotating at least 180° with respect to the object.
Referring to FIG. 1B, a single sinogram 40 may be acquired by combining the first, second, and third raw data 30, 31, and 32 acquired while the X-ray generator 20 is moving at intervals of a predetermined angle as described above with reference to FIG. 1A. The sinogram 40 is acquired via a CT scan performed while the X-ray generator 20 rotates during one cycle. The sinogram 40 corresponding to one cyclic rotation may be used for generation of one cross-sectional CT image. One cyclic rotation may be about more than a half turn or one full turn, according to the specifications of a CT system.
A CT image 50 is reconstructed by performing back-projection with respect to the sinogram 40.
In general, it takes about 0.2 seconds for the X-ray generator 20 to rotate a half turn.
When an object that is a target of a CT scan moves at a relatively fast speed, motion of the object occurs during one cycle. Due to the motion of the object, motion artifacts may occur in the reconstruction of a CT image.
A three-dimensional (3D) CT image may be reconstructed from a plurality of cross-sectional CT images. Thus, while raw data necessary for reconstructing a 3D CT image is being acquired, motion of an object occurs more frequently.
When motion artifacts are present in the reconstructed CT image, an edge of an object may be blurred, or an image may be unclear. The motion artifacts in a CT image degrade the quality of the CT image, and thus when a user, for example, a medical doctor, reads the CT image and diagnoses a disease, the user is unable to accurately read the CT image and diagnose the disease.
Thus, when a CT scan is performed on a moving object, it is important to reconstruct a CT image in which image blurring caused by motion artifacts is reduced.

Tomography apparatus and method of reconstructing a tomography image by the tomography apparatus

KOREA ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY


A flash memory has diffused layers extending in a column direction to form channel regions between each two of the diffused layers, field oxide films extending in a row direction to divide the channel regions into separate channels arranged in a matrix, a floating gate disposed for each channel as a split gate, and a strip control gates extending in the row direction and overlying each row of the split floating gate. Each of the floating gates has a lower layer having a lower impurity concentration and an upper layer having a higher impurity concentration. The lower impurity concentration of the lower layer prevents fluctuations in device characteristics while the higher concentration of the upper layer enhances etch rates in two etching process for forming the floating gates of a matrix.

(a) Field of the Invention
The present invention relates to a non-volatile semiconductor memory device, and in particular, to a nonvolatile semiconductor memory device of a type which enables an electrical erasure by a batch process.
(b) Description of the Related Art
Electrically erasable, programmable memory devices, known as EEPROMs, include a flash memory, which is a type of non-volatile memory enabling a batch erasure. Various structures have been proposed for the flash memory, and include one which is referred to as a virtual ground, split gate type. An EEPROM of this type has two features: (1) the source/drain of a memory cell is used as a buried bit line, and (2) selection transistors called "a split gate type" are connected in series in each memory cell. A conventional flash memory of this type is described, for example, in Patent Publication No. JP-A-1990-292870.
Referring to FIGS. 1 to 4, a typical conventional EEPROM of the virtual ground, split gate type will be described. FIG. 1 is a partial plan view of a cell array of a typical EEPROM of this type, while FIGS. 2 and 3 are sections taken along lines A--A and B--B, respectively, in FIG. 1.
As shown in FIGS. 1 to 3, a plurality of n.sup.+ -buried diffused layers 8, which constitute source/drain regions, are formed on the surface area of a p-silicon substrate 1, and extend in a column direction, i.e., in the vertical direction as viewed in FIG. 1. The n.sup.+ -buried diffused layer 8 is covered by a relatively thick silicon oxide film 9. Element separating insulator films or filed oxide films 2 are formed parallel to one other on the substrate 1, extending in a row direction, i,e, in the direction perpendicular to the buried diffused layers 8. A plurality of floating gates 4 made of polycrystalline silicon are formed in a matrix over the substrate 1, with a gate oxide film 3 being interposed therebetween, in a manner such that part of each of the floating gates 4 overlaps the buried diffused layer 8. A strip control gate 6 made of polycrystalline silicon is formed on top of the floating gate 4, with an intergate oxide film 5 being interposed therebetween, and extends in the row direction perpendicular to the buried diffused layer 8. The surface of the control gate 6 is covered by a silicon oxide film 7.
FIG. 4 shows an equivalent circuit diagram of the cell array shown in FIG. 1. As shown in FIG. 4, the n.sup.+ -buried diffused layers 8 constitute bit lines (B1, B2 . . . ), while the control gates 6 constitute word lines (W1, 2 . . . ). On top of the channel of each memory cell, there are a first portion over which the floating gate 4 and the control gate 6 are disposed in an overlapping relationship and a second portion where the control gate 6 directly opposes the channel, the second portion being a so-called split gate.
The memory operates as follows: A read operation for memory cell (1, 2), for example, i.e., memory cell in first column and second row in FIG. 9, takes place by applying 5 V, for example, to the word line W2, connecting the bit line B1 to the ground, applying 1.5 V to the bit line B2, connecting the remaining word lines W1, W3, W4 . . . to the ground, and leaving the remaining bit lines B3, B4 . . . in a floating state.
A programming operation to memory cell (1, 2) takes place by applying 12 V, for example, to the word line W2, connecting the bit line B1 to the ground, applying 7 V to the bit line B2, and connecting the remaining non-selected word lines W1, W3, W4 . . . to the ground, thus generating in the channel of the selected cell (1, 2) hot electrons which are injected into the floating gate of this cell.
An erase operation of the memory cells takes place by connecting the word line implemented by strip control gate 6 to the ground, and applying 15 V, for example, to the bit lines implemented by n.sup.+ -buried diffused layers 8, thus extracting carriers from the floating gates to the respective source/drain regions of the memory cells.
The conventional EEPROM as described above are manufactured by steps which are summarized below.
(1) Ions are selectively injected into the surface area of p-silicon substrate 1 to form n.sup.+ -buried diffused layer 8.
(2) A silicon oxide film is deposited by a CVD process, and configured in strip patterns extending perpendicular to the n.sup.+ -buried diffused layer 8, thus forming the field oxide films 2.
(3) Gate oxide film 3 is formed by thermal oxidation between the field oxide films 2.
(4) In order to form the floating gate 4, a first polycrystalline silicon film doped with phosphorus at a uniform concentration of 1 E 20/cm.sup.3 (1.times.10.sup.20 atoms/cm.sup.3) or greater is deposited, then configured to exhibit strip patterns which extend parallel to one another and to the n.sup.+ -buried diffused layer 8. The purpose of doping the polycrystalline silicon film with phosphorus, while the film is being formed, is to achieve a film of a uniform concentration over the entire film thickness, and the phosphorus is doped to a high concentration in order to enhance the etch rate and etch selectivity. The structure after the configuring of the first polycrystalline silicon is shown in a perspective view of FIG. 5. The strip polycrystalline silicon films 4a extend parallel to one another in the column direction, which is perpendicular to the field oxide films 2.
5) After formation of the intergate oxide film 5, a second polycrystalline silicon film is deposited and then configured in second strip films which extend parallel to one another and perpendicular to the n.sup.+ -buried diffused layer 8, thus forming the strip control gates 6 extending in the row direction. Subsequently, the first strip films 4a are patterned by using the strip control gate 6 to define separate floating gates 4 arranged in a matrix.
The conventional EEPROM as described above has a drawback in which erasure current or programming current fluctuates from cell to cell in operation of the flash memory, to thereby reduce the throughput of the flash memory.

Method of making non-volatile semiconductor memory device with the floating gate having upper and lower impurity concentrations


It is known to polymerize olefins using transition metal complexes and/or compounds. There is an ongoing search for catalysts for olefin polymerization which do not rely on transition metals as the active center. The present invention provides novel aluminum phosphinimine complexes which are useful in the polymerization of olefins.

The present invention relates to novel aluminum complexes. The complexes are of aluminum and a bridged phosphinimine compound. The complexes may have one aluminum atom or may be a xe2x80x9cdimerxe2x80x9d having two aluminum atoms.
Over the last fifteen years or so there has been an increasing interest in complexes other than the Ziegler-Natta complexes which have the potential to polymerize olefins. The work of EXXON and Dow have lead to the commercialization of metallocene and constrained geometry catalysts which produce polymers tending to have a single active catalyst site. This type of research has lead to more complex ligand structures such as those of Brookhart which also show activity as polymerization catalysts. These systems are used with transition metals as the active catalyst center. There is a desire to find new species which may be capable of olefin polymerization with metals other than the transition metals.
There was a poster presentation by Christopher M. Ong and Professor Douglas W. Stephan of the University of Windsor at the summer meeting of the Chemical Institute of Canada in Toronto which disclosed aluminum phosphinimine complexes. The complex disclosed is a mono aluminum complex having phenyl substituents on the phosphorus atom and trimethyl silyl substituents on the nitrogen atom. The presentation does not disclose the dimer of the present invention.
Jordan et al. JACS 1997, 119, 8125 xe2x80x9cCationic Aluminum Alkyl Complexes Incorporating Amidinate Ligandsxe2x80x9d, teaches amine, imine and aluminum complexes. The paper does not teach complexes of aluminum phosphinimine. The polymerization activity of the complexes of Jordan is very low.
Gibson et al. Chem. Commun. 1998, 2523 xe2x80x9cNovel Aluminum Ethylene Polymerization Catalysts Based on Monoaonic N,N,N,-Pyridyliminoamide Ligandsxe2x80x9d teaches the polymerization of ethylene using a complex with a xe2x80x9cBrookhartxe2x80x9d tridentate ligand and aluminum. Gibson""s catalyst does not teach the complexes of aluminum phosphinimine of the present invention. Further, the polymerization activity of the complexes of Gibson is very low.
The present invention seeks to provide novel aluminum complexes and processes for polymerizing olefins using such complexes.
The present invention provides a process for preparing a complex of aluminum and a bridged phosphinimine comprising reacting moles of a bridged phosphinimine compound of the formula I:
wherein each R1 is independently selected from the group consisting of C1-8 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical; radicals of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals; and R3 is selected from the group consisting of C1-8 alkyl radicals and C6-12 aromatic radicals which are unsubstituted or substituted with one or more halogen atoms or a C1-4 alkyl radical with an aluminum compound of the formula III (Al(R2)3xe2x88x92nXn) wherein each R2 is independently selected from the group consisting of C1-8 alkyl radicals, X is a halogen atom and n is 0, 1, or 2 under an inert atmosphere, in an inert hydrocarbyl solvent or diluent at a temperature from 50xc2x0 C. to 200xc2x0 C. provided that if the molar ratio of compound of formula I to aluminum compound is from 0.8 to 1.20, R3 can not be phenyl if R1 is trimethyl silyl, X is chlorine and n is 2.
The present invention also provides a complex of formula IV:
wherein each R1 is independently selected from the group consisting of C1-8 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical; radicals of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals; R2 is independently selected from the group consisting of C1-8 alkyl radicals, X is a halogen atom and a is 1 or 2; and R3 is selected from the group consisting of C1-8 alkyl radicals and C6-12 aromatic radicals which are unsubstituted or substituted with one or more halogen atoms or a C1-4 alkyl radical.
The present invention further provides a complex of the formula V:
wherein each R1 is independently selected from the group consisting of C1-8 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical; radicals of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals; R2 is independently selected from the group consisting of C1-8 alkyl radicals, X is a halogen atom and a is 1 or 2; and R3 is selected from the group consisting of C1-8 alkyl radicals and C6-12 aromatic radicals which are unsubstituted or substituted with one or more halogen atoms or a C1-4 alkyl radical provided that R3 can not be phenyl if R1 is trimethyl silyl, X is chlorine and n is 2.
The present invention further provides a process for the polymerization of alpha olefins at a temperature from 20xc2x0 C. to 250xc2x0 C. and at a pressure from 15 to 4500 psig in the presence of the complexes of formula IV and an activator selected from the group consisting of:
(i) aluminoxane compounds R202AlO(R20AlO)mAlR202 wherein each R20 is independently selected from the group consisting of C1-20 hydrocarbyl radical and m is from 5 to 30 to provide a molar ratio of aluminum in the activator to aluminum in the complex from 20:1 to 1000:1;
(ii) anions of the formula [B(R18)4]xe2x80x94 wherein each R18 is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted by up to 5 substituents selected from the group consisting of a fluorine atom, a C1-4 alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom and a silyl radical of the formula xe2x80x94Si(R19)3; wherein each R19 is independently selected from the group consisting of a hydrogen atom and a C1-4 alkyl radical; and an activator of the formula [B(R18)3] wherein R18 is as defined above, to provide a molar ratio of B:Al from 0.4 to 1.2; and
(iii) a mixture of (i) and (ii) above.
The present invention further provides a process for polymerizing one or more C2-8 olefins at a temperature from 20xc2x0 C. to 120xc2x0 C. and at a pressure from 15 to 4500 psig in the presence of a complex of the formula V:
wherein each R1 is independently selected from the group consisting of C1-8 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical; radicals of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals; R2 is independently selected from the group consisting of C1-8 alkyl radicals, X is a halogen atom and a is 1 or 2; and R3 is selected from the group consisting of C1-8 alkyl radicals and C6-12 aromatic radicals which are unsubstituted or substituted with one or more halogen atoms or a C1-4 alkyl radical and an activator selected from the group consisting of:
(i) aluminoxane compounds R202AlO(R20AlO)mAlR202 wherein each R20 is independently selected from the group consisting of C1-20 hydrocarbyl radical and m is from 5 to 30 to provide a molar ratio of aluminum in the activator to aluminum in the complex from 20:1 to 1000:1;
(ii) anions of the formula [B(R18)4]xe2x80x94 wherein each R18 is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted by up to 5 substituents selected from the group consisting of a fluorine atom, a C1-4 alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom and a silyl radical of the formula xe2x80x94Si(R19)3; wherein each R19 is independently selected from the group consisting of a hydrogen atom and a C1-4 alkyl radical; and an activator of the formula [B(R18)3] wherein R18 is as defined above, to provide a molar ratio of B:Al from 0.8 to 1.2; and
(iii) a mixture of (i) and (ii) above.
The term xe2x80x9cscavengerxe2x80x9d as used in this specification is meant to include those compounds effective for removing polar impurities from the reaction solvent. Such impurities can be inadvertently introduced with any of the polymerization reaction components, particularly with solvent, monomer and catalyst feed; and can adversely affect catalyst activity and stability. It can result in decreasing or even elimination of catalytic activity, particularly when an activator capable of ionizing the catalyst is also present.
In the complexes of the present invention each R1 may be independently selected from the group consisting of C1-8 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical; and radicals of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals.
If R1 is a hydrocarbyl radical it may be selected from the group consisting of a C1-4 straight or branched alkyl radical or a C6-12 cyclic aliphatic or aromatic radical. Suitable hydrocarbyl radicals include methyl, ethyl, propyl, butyl, iso-butyl, tert-butyl and phenyl radicals.
In the complexes of formula V, R1 may be a silyl radical of the formula Si(R4)3 wherein each R4 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals, preferably R4 is selected from the group consisting of C1-4 alkyl radicals. It should be noted that when R4 is methyl, R3 can not be phenyl, X can not be chlorine and n can not be 2.
In the complexes of the present invention R3 may be selected from the group consisting of consisting of C1-8 alkyl radicals and C6-12 aromatic radicals which are unsubstituted or substituted with one or more halogen atoms or a C1-4 alkyl radical. Suitable radicals include C1-4 straight chained or branched alkyl radicals and C6-12 cyclic aliphatic or aromatic radicals. These radicals include methyl, ethyl, propyl, butyl, iso-butyl, tert- butyl, and phenyl radicals.
In some embodiments of the present invention the R1 substituents are the same. In some embodiments of the present invention the R3 substituents are the same.
The bridged phosphinimine compound of formula I above may be reacted with an aluminum compound of formula III (Al(R2)3xe2x88x92nXn) wherein each R2 is independently selected from the group consisting of C1-8 alkyl and alkoxy radicals, X is a halogen atom and n is 0, 1, or 2. In some embodiments of the present invention R2 may be selected from the group consisting of C1-4 alkyl radicals. Suitable halogen atoms include chlorine atoms.
If the bridged phosphinimine compound of formula I is reacted with from about 0.8 to about 1.2, preferably from about 0.95 to about 1.05 moles of the aluminum compound of formula III per mole of phosphinimine; a compound of formula V:
wherein R1 and R3 are as defined above, is obtained.
The bridged phosphinimine compound of formula I above may be reacted with an aluminum compound of formula III (Al(R2)3xe2x88x92nXn) wherein each R2 is independently selected from the group consisting of a C1-8 alkyl radical, X is a halogen atom and n is 0 or 1. In some embodiments of the present invention R2 may be selected from the group consisting of C1-4 alkyl radicals. Suitable halogen atoms include chlorine atoms.
If the bridged phosphinimine compound of formula I is reacted with from about 1.8 to about 2.2, preferably from about 1.95 to about 2.05 moles of the aluminum compound of formula III per mole of phosphinimine; a compound of formula IV:
wherein R1, R2 and R3 are as defined above, is obtained.
The reaction is conducted under an inert atmosphere, such as argon, in an inert solvent or diluent such as a hydrocarbyl solvent or diluent at temperature from about 50xc2x0 C. to 200xc2x0 C., preferably from about 120xc2x0 C. to 180xc2x0 C.
The resulting compounds of either formula V or IV may then be used to polymerize one or more olefins, generally alpha olefins, typically having from 2 to 10, preferably 8 carbon atoms or less. Illustrative non-limiting examples of such alpha-olefins are one or more of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene.
The compound and an activator are dissolved or suspended in an inert solvent or diluent such as a hydrocarbyl solvent or diluent in the presence of an activator and the ethylene is introduced into the reaction vessel.
The polymerization may be conducted at temperatures from about 20 to about 250xc2x0 C. Depending on the product being made, this temperature may be relatively low such as from 20xc2x0 C. to about 120xc2x0 C. (desirably 119xc2x0 C. or less) for a slurry polymerization or from about 120xc2x0 C. to 250xc2x0 C. for a solution polymerization. The pressure of the reaction may be as high as about 15,000 psig (103.5 MPa gauge) (for the older high pressure processes) or may range from about 15 to 4,500 psig (0.1035 MPa gauge to about 31.01 MPa gauge).
Solution polymerization processes are fairly well known in the art. These processes are conducted in the presence of an inert hydrocarbon solvent typically a C5-12 hydrocarbon which may be unsubstituted or substituted by C1-4 alkyl group such as pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane or hydrogenated naphtha. An additional solvent is Isopar E (C8-12 aliphatic solvent, Exxon Chemical Co.).
The polyethylene polymers which may be prepared in accordance with the present invention typically comprise not less than 60, preferably not less than 70, most preferably not less than 80 weight % of ethylene and the balance of one or more C4-10 alpha olefins, preferably selected from the group consisting of 1-butene, 1-hexene and 1-octene.
The activator may be selected from the group consisting of:
(i) an aluminoxane; and
(ii) an activator capable of ionizing the catalyst (which may be used in combination with an alkylating activator).
The aluminoxane activator may be of the formula (R20)2AlO(R20AlO)mAl(R20)2 wherein each R20 is independently selected from the group consisting of C1-20 hydrocarbyl radicals, m is from 0 to 50, and preferably R20 is a C1-4 alkyl radical and m is from 5 to 30. The aluminoxane activator may be used prior to the reaction but preferably in situ alkylation is typical (e.g. alkyl groups replacing leaving ligands, hydrogen or halide groups).
Activation with aluminoxane generally requires a molar ratio of aluminum in the activator to the catalyst from 20:1 to 1000:1.
The activator of the present invention may be a combination of an alkylating activator which also serves as a scavenger other than aluminoxane in combination with an activator capable of ionizing the catalyst.
The alkylating activator (which may also serve as a scavenger) may be selected from the group consisting of: (R)pMgX2xe2x88x92p wherein X is a halide, each R is independently selected from the group consisting of C1-10 alkyl radicals, preferably C1-8 alkyl radicals and p is 1 or 2; (R)qZnX2xe2x88x92q wherein R is as defined above, X is halogen and q is 1 or 2; (R)sAlX3xe2x88x92s wherein R is as defined above, X is halogen and s is an integer from 1 to 3. Preferably, in the above compounds R is a C1-4 alkyl radical and X is chlorine. Commercially available compounds include triethyl aluminum (TEAL), diethyl aluminum chloride (DEAC), dibutyl magnesium ((Bu)2Mg) and butyl ethyl magnesium (BuMgEt).
The activator capable of ionizing the catalyst may be selected from the group consisting of:
(i) compounds of the formula [R15]+[B(R18)4]xe2x80x94 wherein B is a boron atom, R15 is a cyclic C6-7 aromatic cation or a triphenyl methyl cation and each R18 is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted with from 3 to 5 substituents selected from the group consisting of a fluorine atom, a C1-4 alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom, and a silyl radical of the formula xe2x80x94Sixe2x80x94(R19)3 wherein each R19 is independently selected from the group consisting of a hydrogen atom and a C1-4 alkyl radical; and
(ii) compounds of the formula [(R16)tZH]+[B(R18)4]xe2x80x94 wherein B is a boron atom, H is a hydrogen atom, Z is a nitrogen atom or phosphorus atom, t is 3 and R16 is selected from the group consisting of C1-8 alkyl radicals, a phenyl radical which is unsubstituted or substituted by up to three C1-4 alkyl radicals, or one R16 taken together with the nitrogen atom to form an anilinium radical and R18 is as defined above; and
(iii) compounds (activators) of the formula B(R18)3 wherein R18 is as defined above.
In the above compounds, preferably R18 is a pentafluorophenyl radical, R15 is a triphenylmethyl cation, Z is a nitrogen atom and R16 is a C1-4 alkyl radical or R16 taken together with the nitrogen atom to form an anilinium radical which is substituted by two C1-4 alkyl radicals.
The activator capable of ionizing the catalyst abstracts one or more R2 substituents so as to ionize the catalyst center into a cation, but not to covalently bond with the catalyst; and to provide sufficient distance between the ionized catalyst and the ionizing activator to permit a polymerizable olefin to enter the resulting active site. Examples of compounds capable of ionizing the catalyst include the following compounds:
triethylammonium tetra(phenyl)boron,
tripropylammonium tetra(phenyl)boron,
tri(n-butyl)ammonium tetra(phenyl)boron,
trimethylammonium tetra(p-tolyl)boron,
trimethylammonium tetra(o-tolyl)boron,
tributylammonium tetra(pentafluorophenyl)boron,
tributylammonium tetra(pentafluorophenyl)boron,
tri(n-butyl)ammonium tetra(o-tolyl)boron,
N,N-dimethylanilinium tetra(phenyl)boron,
N,N-diethylanilinium tetra(phenyl)boron,
N,N-diethylanilinium tri(phenyl)n-butylboron,
N,N-2,4,6-pentamethylanilinium tetra(phenyl)boron,
di-(isopropyl)ammonium tetra(pentafluorophenyl)boron,
dicyclohexylammonium tetra(phenyl)boron,
triphenylphosphonium tetra(phenyl)boron,
tri(methylphenyl)phosphonium tetra(phenyl)boron,
tri(dimethylphenyl)phosphonium tetra(phenyl)boron,
tropillium tetrakispentafluorophenyl borate,
triphenylmethylium tetrakispentafluorophenyl borate,
benzene (diazonium) tetrakispentafluorophenyl borate,
tropillium phenyltrispentafluorophenyl borate,
triphenylmethylium phenyltrispentafluorophenyl borate,
benzene (diazonium) phenyltrispentafluorophenyl borate,
tropillium tetrakis (2,3,5,6-tetrafluorophenyl) borate,
triphenylmethylium tetrakis (2,3,5,6-tetrafluorophenyl) borate,
benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,
tropillium tetrakis (3,4,5-trifluorophenyl) borate,
benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,
tropillium tetrakis (1,2,2-trifluoroethenyl) borate,
triphenylmethylium tetrakis (1,2,2-trifluoroethenyl) borate,
benzene (diazonium) tetrakis (1,2,2-trifluoroethenyl) borate,
tropillium tetrakis (2,3,4,5-tetrafluorophenyl) borate,
triphenylmethylium tetrakis (2,3,4,5-tetrafluorophenyl) borate, and
benzene (diazonium) tetrakis (2,3,4,5-tetrafluorophenyl) borate.
Readily commercially available activators which are capable of ionizing the catalyst include:
N,N-dimethylaniliniumtetrakispentafluorophenyl borate,
triphenylmethylium tetrakispentafluorophenyl borate, and
trispentafluorophenyl boron.
If the catalyst is a mono aluminum compound (e.g., of formula V) and the activator is ionic (i.e., a boron compound) the molar ratio of boron in the activator to aluminum in the complex may be from about 0.8 to about 1.2, preferably from about 0.9 to 1.1. If the aluminum compound contains two aluminum atoms (e.g. the xe2x80x9cdimerxe2x80x9d) the molar ratio of boron in the activator to aluminum in the complex may be from about 0.4 to about 1.2, preferably from about 0.5 to 1.1.
If the aluminum compound of formula IV or V is activated with a combination of an aluminum alkyl compound (which may include aluminoxane), and a compound capable of ionizing the catalyst; the molar ratios of aluminum in the compound of formula IV or V:metal in the alkylating agent (e.g. Al):metalloid (e.g. boron or phosphorus) in the activator capable of ionizing the catalyst (e.g. boron) may range from 1:1:1 to 1:100:5 for the complexes of formula V and from 1:1:0.4 to 1:100:5 for complexes of formula IV.
Preferably, the alkylating activator is premixed/reacted with the catalyst and the resulting alkylated species is then reacted with the activator capable of ionizing the catalyst.
It is believed the complexes of the present invention may be used in the presence of a support. An exemplary list of support materials include metal oxides (such as silica, alumina, silica-alumina, titania and zirconia); metal chlorides (such as magnesium chloride); talc, polymers (including polyolefins); partially prepolymerized mixtures of a group 4 metal complex, activator and polymer; spray dried mixtures of the group 4 metal complex, activator and fine xe2x80x9cinertxe2x80x9d particles (as disclosed, for example, in European Patent Office Application 668,295 (to Union Carbide)).
A typical support material is silica. The silica may be pre-treated with an aluminoxane (especially methylaluminoxane or xe2x80x9cMAOxe2x80x9d) prior to the deposition of the aluminum complex. The procedure for preparing xe2x80x9csupported MAOxe2x80x9d which is described in U.S. Pat. No. 5,534,474 (to Witco) is preferred for reasons of economy. It will be recognized by those skilled in the art that silica may be characterized by such parameters as particle size, pore volume and residual silanol concentration. The pore size and silanol concentration may be altered by heat treatment or calcining. The residual silanol groups provide a potential reaction site between the aluminoxane and the silica (and, indeed, some off gassing is observed when aluminoxane is reacted with silica having residual silanol groups). This reaction may help to xe2x80x9canchorxe2x80x9d the aluminoxane to the silica (which, in turn, may help to reduce reactor fouling).
The particle size, pore volume and residual silanol concentration may be influenced by reactor conditions. Typical silicas are dry powders having a particle size from 1 to 200 microns (with an average particle size from 30 to 100 being especially suitable); pore size from 50 to 500 Angstroms; and pore volumes of from 0.5 to 5.0 cubic centimeters per gram. As a general guideline, the use of commercially available silicas, such as those sold by W. R. Grace under the trademarks Davison 948 or Davison 955, are suitable.
In a solution polymerization, the monomers are dissolved/dispersed in the solvent either prior to being fed to the reactor or for gaseous monomers, the monomer may be fed to the reactor so that it will dissolve in the reaction mixture. Prior to mixing, the solvent and monomers are generally purified to remove polar moieties. The polar moieties or catalyst poisons include water, oxygen, metal impurities, etc. Preferably steps are taken before provision of such into the reaction vessel, for example by chemical treatment or careful separation techniques after or during the synthesis or preparation of the various components. The feedstock purification prior to introduction into the reaction solvent follows standard practices in the art (e.g. molecular sieves, alumina beds and oxygen removal catalysts) are used for the purification of ethylene, alpha-olefin and optional diene. The solvent itself as well (e.g. cyclohexane and toluene) is similarly treated. In some instances, out of an abundance of caution, excess scavenging activators may be used in the polymerization process.
The feedstock may be heated prior to feeding into the reactor. However, in many instances it is desired to remove heat from the reactor so the feedstock may be at ambient temperature to help cool the reactor.
Generally, the components may be premixed in the solvent for the reaction or fed as separate streams to the reactor. In some instances, premixing is desirable to provide a reaction time for the catalyst components prior to entering the reaction. Such an xe2x80x9cin line mixingxe2x80x9d technique is described in a number of patents in the name of DuPont Canada Inc. For example, it is described in U.S. Pat. No. 5,589,555 issued Dec. 31, 1996.
The reactor may comprise a tube or serpentine reactor used in xe2x80x9chigh pressurexe2x80x9d polymerizations or it may comprise one or more reactors or autoclaves. It is well known that the use in series of two such reactors each of which may be operated so as to achieve different polymer molecular weight characteristics. The residence time in the reactor system will depend on the design and the capacity of the reactor. Generally, the reactors should be operated under conditions to achieve a thorough mixing of the reactants. On leaving the reactor system, the solvent is removed and the resulting polymer is finished in a conventional manner.

Aluminum complexes for olefin polymerization

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