An expression vector containing both a DNA encoding an L-sorbose dehydrogenase and a DNA encoding an L-sorbosone dehydrogenase; a transformant having an ability to produce 2-keto-L-gulonic acid (hereinafter 2KLGA) at high yields from D-sorbitol, which is prepared by transforming, with said expression vector, a microorganism capable of producing L-sorbose at high yields from D-sorbitol, which has no or low 2KLGA-decomposing activity or a host microorganism having, in addition to the above-mentioned properties, no or low L-idonic acid-producing activity; and a process for producing 2KLGA, which comprises culturing said transformant in a medium containing D-sorbitol. According to the present invention, 2KLGA useful for the production of L-ascorbic acid can be produced with ease and in larger amounts by a single operation of culture.

The 2KLGA is a key intermediate in the synthesis of L-ascorbic acid. For industrial production, 2KLGA is chemically synthesized from D-sorbitol by oxidation according to the Reichstein's method. Meanwhile, many microorganisms inclusive of the microorganisms belonging to the genus Gluconobacter are known to convert D-sorbitol to 2KLGA through an enzymatic oxidation. The microorganisms belonging to the genus Gluconobacter have been improved by genetic engineering using conjugal transfer and transposon. However, because of the low production of 2KLGA by these microorganisms, they have not been utilized in the industrial production yet.
Accordingly, there has been a desire for a more efficient and simplified method for the production of 2KLGA.
It is also well known that, in secondary metabolite production by microorganisms such as that of 2KLGA, a mere insertion of a gene (group) responsible for the biosynthesis of a substance into a plasmid and culture of the cells of microorganism, which have been recombined with this plasmid, does not necessarily result in an improved production of the desired substance, but rather, may degrade the productivity Thomas, D. I. et al., J. Gen. Microbiol., 137, pp. 2331-2337 (1991)!.

Method for producing 2-keto-L-gulonic acid


A dual adjustable feather jig for simultaneously holding a piece of wood stock firmly against a stationary rip fence and against the top surface of a worktable. The feather jig includes a lower feather board with a ‘T’ in channel bar adjustably mounted on the bottom surface of the lower feather board to laterally adjust the lower feather board over the worktable. Mounted transversely on the lower feather board is an upper feather board assembly that includes a vertical feather board to hold the wood piece against the worktable. The vertical feather board is connected to a slider arm that slides longitudinally over a riser block securely mounted to the lower feather board. Formed on the lateral and lower edges of the lower and vertical feather boards, respectively, are diagonally aligned fingers that press the wood piece against the rip fence and against the top surface of the worktable.

1. Field of the Invention
2. Description of the Related Art
Table saws and router tables (herein after often include a rip fence attached to the top surface of the table and parallel to the saw blade. Most worktables also include a 'T' slot formed on the top surface of the table that extends parallel to the rip fence and on the side of the saw blade or router bit opposite the rip fence. The 'T' slot is designed to receive a 'T' channel attached to the bottom surface of a miter guide that is used to push the wood stock towards the saw blade or router bit.
Heretofore, adjustable feather boards have been used on table saws to 'cut' a piece of wood stock in a longitudinal direction parallel with the grain. Feather boards typically include a set of fingers located along one edge that press the piece of wood stock against the rip fence and prevents it from drifting during the cutting or routing operation.
When cutting a piece of wood stock longitudinally (also, called ripping) or when shaping the wood stock with a router bit, it is also important to firmly hold the wood stock downward against the top surface of the worktable.
Because many rip fences used today are not securely held down at both ends to the worktable, mounting a vertical feather board to the rip fence is undesirable because the rip fence may rise off the worktable. Also, it is impossible to laterally reposition the vertical feather board with respect to the rip fence if the vertical feather board is directly clamped to the rip fence.
Unfortunately, no device exists today that simultaneously holds the wood stock firmly against the rip fence and firmly against the top surface of the worktable.


An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest.

1. Field of the Invention
The present invention relates to devices for detecting electrical wiring. More particularly, the present invention relates to devices for identifying and marking the location of electrical wiring that is partially or completely concealed.
2. Discussion of Background
The use of electrical transmitters and receivers for detecting hidden conductors is known. Grove, U.S. Pat. No. 1,241,963, and Iddings, et al. U.S. Pat. No. 658,013, disclose electrical means for locating concealed pipes. After energizing the pipe system of interest, an exploring coil connected to one or more receivers is surveyed along the area of interest. The coil provides audible notification when the coil passes directly over and along the length of the pipe.
U.S. Pat. No. 1,212,763, issued to Gregory, uses an induction device to produce a high frequency AC current through a concealed conductor. The detector consists of a cylindrical coil with a magnetic coil, connected to a telephone receiver. The receiver produces a distinct buzzing sound when the plane of the detector coincides with the conductor. The conductor can then be traced by moving the detector.
Although numerous devices exist for detecting hidden conductors, there is a need for a more convenient and thorough detection method. Such a method would use a device that is compact, inexpensive, portable, simple to use, accurate, and foolproof. There is also a need for a reliable method of marking or recording the path of the detected conductors.

The United States of America as represented by the United States Department of Energy


A hydraulic closer and dampener that can be removed and replaced by opening a post cap to then lift an internal closer assembly out of the top of an internally pivotable shaft inside a free-standing floor-mounted post. The remainder of the gate mechanism remains functional during such service. An automatic closing speed adjustment is easy to access and set. There are no external hinges, the gate pivots on an axis coaxial to the cylindrical post.

1. Field of the Invention
The present invention relates to industrial pedestrian control gates and fences as used in metro-stations, and more particularly to hollow, cylindrical, floor mounting gate posts with closing dampeners that allow the gate to hinge on an axis coaxial to the post.
2. Description of Related Art
Train, airline, bus, and other transportation stations all employ gates and turnstiles to control and secure various areas. These gates very often have to be able to swing both ways, and some also need to be able to latch securely.
Station agents in secure booths often need to be able to unlock the gates briefly to let authorized riders and ticketholders through. Very often the way this is done in conventional systems is to use an electro-mechanical lock mechanism at the gate with wires buried in the ground or installed in the floors and walls connected to a control switch in the secure booth.
Such lock systems must survive energetic efforts by criminals to kick the gates down, and still be failsafe in the event of a power failure. The gates must unlatch when power is lost so as to not trap people from escape. David Dudley describes such a locking mechanism for a bi-swing train station gate in U.S. Pat. No. 8,186,729, issued May 29, 2012, titled TRAPLOCK FOR BI-SWING GATE (Dudley '729).
Conventional gate and post construction used throughout America are difficult and expensive to manufacture, install, operate, and maintain. What is needed is a gate system with a post mechanism that is easy and inexpensive to manufacture, install, operate, and maintain. One key to all of this is the elimination of external hinges.

Floor-mounting gate-closer post with rotary dampener


The present invention relates to oxidation-stable iron oxide pigments which have a coating of at least one organic substance, to their preparation and to their use.

1. Field of the Invention
The present invention relates to oxidation-stable iron oxide pigments which have a coating of at least one organic substance, to their preparation and to their use.
Iron oxide pigments containing iron in the +2 oxidation state constitute thermodynamically unstable phases in comparison to iron(III) oxide, Fe2O3. In the presence of air or oxygen they may undergo full or partial oxidation, for example2Fe3O4+½O2→3Fe2O3
Such reactions are known, for example, in the case of black iron oxide pigments which correspond in terms of their composition and structure to magnetite. As a result of the oxidation the pigment suffers loss in its most important quality, the color, and hence becomes unusable. The propensity to undergo oxidation increases in line with the degree of fine division and thus with the specific surface area of the pigments.
The same applies to mixtures of black iron oxide with other iron oxide color pigments—red iron oxide and/or yellow iron oxide—as are produced for brown shades.
If with the color pigments it is the loss of coloristic properties that makes them unusable, then with the iron(II)-containing magnetic pigments it is the loss of the magnetic properties, which is induced likewise as a result of oxidation. Particularly at risk are finely divided magnetite pigments and also mixed phases between magnetite (Fe3O4) and maghemite (γ-Fe2O3) with a high iron(II) content. Also sensitive to oxidation, however, are mixed phases of magnetite and/or ferrites, such as cobalt ferrite, for example, and those magnetic pigments which are composed of a core of Fe3O4 and γ-Fe2O3 that is surrounded by a shell of magnetic metal oxides—particularly of iron and of cobalt. In the technical literature one finds, besides the mixed phase designation, the expression "berthollides" for the compositions described here.
2. Brief Description of the Prior Art
DE 27 44 598 A1 discloses reducing the oxidation sensitivity of finely divided ferrimagnetic magnetite particles by treatment with heterocyclic organic compounds. This treatment provides a considerable improvement over the untreated pigments, but one which cannot be raised above a certain level. Morpholine, N-(3-aminopropyl)morpholine, N-(2-hydroxyethyl)piperazine, 1,2,4-triazole and 3-amino-1,2,4-triazole have proved to be particularly effective. The heterocycles used are merely physisorbed on the pigment and are therefore among the water-soluble constituents. This may result in incompatibilities in different binder systems. The magnetite particles are treated with the heterocyclic organic compound, moreover, under a non-oxidizing atmosphere, and the presence of air must be ruled out. The process is therefore costly and complicated.
DE 41 39 052 A1 discloses iron oxide pigments which in order to increase the stability towards atmospheric oxidation are coated with cyclic carboxylic hydrazides of the general formula

Preference is given to using "phthalic hydrazide" and "maleic hydrazide". When looked at more closely, however, all of the compounds of the general formula given above are merely 3,6-dihydroxy-substituted derivatives of pyridazine, since for the compounds of the general formula given above the following tautomeric form exists:

For "phthalic hydrazide" and "maleic hydrazide", therefore, the names 1,4-dihydroxyphthalazine and 3,6-dihydroxypyridazine, respectively, are also customary. Thus the cyclic carboxylic hydrazides disclosed in DE 41 39 052 A1 are simple nitrogen-containing heterocycles. As already mentioned above, these are merely physisorbed on the pigment and are therefore included among the water-soluble constituents. This may result in incompatibilities in different binder systems.
DE 37 26 048 A1 describes a coating of iron oxide pigments with derivatives of benzoic acid conforming to the general formula
where    X═O or NH and    R=an optionally substituted linear or branched alkyl or alkylene radical having 1 to 30 carbon atoms or an optionally substituted cycloalkyl radical having 5 to 12 carbon atoms or an optionally substituted aryl radical having 5 to 10 carbon atoms or hydrogen. Particular preference is given to salicylic esters containing aliphatic alcohol components having 2 to 18 carbon atoms, such as octyl salicylate or dodecyl salicylate, for example. The derivatives of benzoic acid of the general formula that are used are merely physisorbed on the pigment and are therefore included among the water-soluble constituents. This may result in incompatibilities in different binder systems.
The prior art also describes numerous inorganic coatings, and coatings of mixtures of organic and inorganic substances, for the purpose of enhancing the oxidation stability of iron oxide pigments.
DE 32 11 327 A1, for instance, describes aftertreatment with boron-containing compounds. Those contemplated include ortho-boric acid, tetra-boric acid, meta-boric acid, glassy diboron trioxide, crystalline diboron trioxide, trimethyl borate, triethyl borate, complexes of boric acid with polyhydroxy compounds, and salts of boric acids, such as NH4B5O8*4H2O, Na2B4O6*10H 2O, CaB3O5OH*2H2O or NaBO2, for example. As well, boron/nitrogen compounds or boron-sulphur compounds are mentioned. Preference as boron compounds is given to using boron oxides, boric acids and/or salts of boric acids, with particular preference ortho-boric acid and/or diboron trioxide. In the examples disclosed, pulverized ortho-boric acid and pulverized diboron trioxide are added. The oxidation stability of the pigments stabilized with boric acid is comparable with that of the pigments coated with heterocyclic compounds, with a reduction in the water-soluble fractions at the same time.
DE 43 22 886 A1 discloses iron oxide pigments which have been coated with oxides or hydroxides of boron, of aluminum and/or of silicon, and also with aromatic carboxylic acids of the general formulaAr—(COOX)nwhere Ar is an aromatic optionally substituted by halogen, NH2, OH, NHR, NR2, OR or R, in which R is a linear or branched alkyl radical having 1 to 30 carbon atoms or an optionally substituted aryl radical having 6 to 10 carbon atoms, and X is hydrogen, alkali metal, NR14 with R1═H, alkyl and/or aryl, ½ alkaline earth metal, ⅓ Al or ⅓ Fe, and n is an integer from 1 to 10. In the examples disclosed, mixtures of boric acid and benzoic acid or of boric acid and 4-hydroxybenzoic acid are added.
A committee of experts of the European Union has proposed classing boric acid, borates of ortho-boric acid, such as Na3BO3, and of tetra-boric acid, such as Na2B4O6*10H2O or Na2B4O6*5H2O, for example, and also diboron trioxide, as toxic to reproduction in category 2 (substances which on the basis of clear findings from animal experimentation or of other relevant information should be regarded as embryotoxic or as impairing fertility in humans) and as "toxic" (hazard symbol T) (see the Summary Record of a consultation in connection with the EU "Commission Working Group of Specialized Experts in the Field of Reprotoxicity", Ispra, 5-6 Oct. 2004—date of Record: 22 Nov. 2004). On 8 Sep. 2005 the EU Technical Committee "Classification and Labeling" dealt conclusively with the compounds specified above. By a majority decision the recommendation of the committee of experts was followed, and for these classes of substance the classification "toxic to reproduction category 2" recorded. The R phrases that apply are 60 (May impair fertility) and 61 (May cause harm to the unborn child), and also the hazard symbol T ("toxic") applies (see Summary Record of the meeting of EU Technical Committee "Classification and Labelling", Arona, 8 Sep. 2005). Handling these substances, or using them in a production operation for stabilizing the iron(II)-containing iron oxide pigments, therefore requires corresponding measures in order to protect employees and the environment. For this reason the replacement of the abovementioned compounds is desirable.
It was an object of the present invention, therefore, to provide oxidation-stable iron(II)-containing iron oxide pigments whose oxidation stability is at least as good as that of boron-containing iron oxide pigments but which can be prepared in one step, without the use of inorganic substances, using commercially customary organic substances.

Oxidation-stable iron oxide pigments, process for preparing them and their use


A method is provided for writing into a semiconductor memory which includes a MOS transistor formed on a semiconductor substrate and an anti-fuse formed of an insulating film and an upper electrode on a drain of the MOS transistor. The method includes the steps of applying a first voltage between the upper electrode of the anti-fuse and a source of the MOS transistor to cause dielectric breakdown of the insulating film of the anti-fuse, with the MOS transistor turned on; and applying a second voltage between the upper electrode of the anti-fuse and the semiconductor substrate so that a larger amount of current flows than the amount of current required for breaking down the insulating film of the anti-fuse.

1. Field of the Invention
The present invention relates to a method for writing into a semiconductor memory, and more particularly, it relates to a method for writing into a semiconductor memory which has a memory cell composed of a MOS transistor and an anti-fuse connected to the MOS transistor in series.
2. Related Art
In recent years, as shown in FIG. 2, a PROM memory cell M is known to include an n-channel MOS transistor 8 formed on a surface of a p-type semiconductor substrate 1 and an anti-fuse 7 connected to the MOS transistor 8 in series (e.g., "Dielectric Based Anti-fuse for Logic and Memory IC", IEDM 88, pp. 786-789). The anti-fuse 7 is formed by providing a thin insulating film 10 and an upper electrode 5 on a drain 3 of the MOS transistor 8, as shown in FIG. 3. Reference numeral 2 denotes a local oxidation film for isolating the memory cell M, while numeral 4 denotes a gate electrode. When some information is written in the memory cell M, first, a positive voltage is applied to the gate electrode 4 to turn the MOS transistor 8 on. For keeping the MOS transistor 8 in an ON state, a voltage V.sub.p which can break down the thin insulating film 10 (where the voltage Vp varies depending on the thickness of the thin insulating film 10, for example, if the thickness of the thin insulating film 10 is 50 .ANG., 10 to 15 V is necessary to breakdown the thin insulating film 10) is applied between the upper electrode 5 of the anti-fuse 7 and a source 6 of the MOS transistor 8 in such a direction that the upper electrode 5 turns positive while the source 6 turns negative with respect to electrode 5. In other words, voltage is applied through the MOS transistor 8 to the anti-fuse 7. Then, the insulating film 10 of the anti-fuse 7 is subjected to dielectric breakdown to make the anti-fuse 7 conductive. At this stage, conventionally, the writing operation is completed.
The basic cell construction includes a MOS transistor formed on the semiconductor substrate 1 and the anti-fuse 7 connected to the upper electrode 5 with the thin insulating film 10 as an intermediate covering the MOS transistor, wherein a portion of the thin insulating film 10 lying over the drain 3 is intended to become conductive. As a result, the thin insulating film 10 lying at that portion is made thinner than the thin insulating film lying in other portions. With such a design and with the MOS transistor turned ON, an application of a voltage on the upper electrode 5 breaks down only the insulating film 10 and forms conduction therethrough, wherein a portion of the upper electrode 5 lying over the portion of the insulating film 10 acts as the anti-fuse 7. Accordingly, other memory cells which were not subjected to such writing actions are left as each upper electrode 5 is not made conductive or insulated from the drain 3.
The dielectric breakdown of the anti-fuse 7 is caused by a current in the order of a few .mu. amperes (where this breakdown current changes depending on the characteristics of the MOS transistors). The electrical resistance of the anti-fuse 7 after the dielectric breakdown depends upon the current at the time of the dielectric breakdown. The electric resistance is reduced as the current is increased, while the electric resistance increases as the current decreases. When voltage is applied through the MOS transistor 8 to the anti-fuse 7 in a conventional manner, merely applying the voltage V.sub.p of the order of a few volts leads to a current limit, and the reduction in the electric resistance of the anti-fuse 7 may be limited. As a result, as shown in FIG. 1(a), there arises the problem that, upon the operation of the memory cell M, a voltage-current (V-I) characteristic is shown which curves in a low current range of 5 mA or below (a part shown by an arrow in the drawing), for expressing a non-linearity of the characteristic. The problem becomes more critical as miniaturization of the MOS transistor advances more and more. Since there is a limitation to the supply voltage, the voltage V.sub.p to be applied cannot be so large.
(An anti-fuse element includes that which is disclosed in the U.S. Pat. No. 4,899,205, for example.)

Method for writing into semiconductor memory


An engine control apparatus for controlling an engine which drives a hydraulic pump to discharge operation oil, the engine control apparatus includes: a pump driving power limit unit configured to limit pump driving power, which is power used to drive the hydraulic pump, based on pressure of the operation oil discharged by the hydraulic pump when in a state in which a part of the operation oil discharged by the hydraulic pump is released because pressure of the operation oil discharged by the hydraulic pump has become equal to or higher than preset relief pressure; and an engine output control unit configured to control output of the engine so that target speed, which is speed of the engine set as a target, becomes equal to or higher than a value of a point of time when limiting of the pump driving power is started.

A construction machine, such as an excavator, a bulldozer, a dump truck, or a wheel loader, is provided with a hydraulic pump, which is driven by an engine, in order to supply operation oil to a hydraulic actuator, which is used to actuate a working machine or a vessel. For example, Patent Literature 1 discloses control of lowering an engine speed, not limiting a pump absorption torque, when a hydraulic pump reaches a relief state in connection with driving a hydraulic pump by a diesel engine.

Engine control apparatus and construction machine


A polymerization process for olefinically or acetylenically unsaturated monomers is disclosed. The process comprises contacting the one or more of the monomers with a suitable ionic catalyst system in the presence of a long-chain, linear alkyl ligand-containing organo aluminum compound. Preferred ionic catalysts are derived from 1) bridged hafnium compounds, 2) silicon bridged monocyclopentadienyl titanium compounds and 3) unbridged, bulky Group 15 containing, bulky monocyclopentadienyl titanium compounds, and a non-coordinating anion precursor compound. A class of preferred anion precursors consists of hydrated salts comprising a Group 1 or 2 cation and a non-coordinating anion. Using the preferred ionic catalysts high temperature processes, e.g., at or above 90.degree. C. can be conducted to prepare polyolefins, particularly ethylene copolymers, of both high molecular weight and high comonomer content.

Ionic catalyst systems for olefin polymerization based on transition metal compounds such as metallocene compounds are recent but now well-known. Such metallocene compounds are based on transition metals capable of supporting at least one pi-bound aromatic ligand, typically a cyclopentadienyl or substituted cyclopentadienyl ligand and at least one additional ligand which can be abstracted so as to form a catalytically active cation structure. Co-catalyst anions are needed to stabilize these cations, which are highly reactive, but those anions must be capable of doing so without either closely coordinating with the cation that its reactivity, and thus polymerization activity, is diminished, or transferring an anionic fragment to the cation so as to alter its polymerization capability. Single coordination complexes and multi-nuclear coordination complexes based on the Group IIIA or 13 elements, such as boron or aluminum, have shown particular suitability as effective co-catalyst anion sources. See, the disclosures in EP-A-0 277 003, EP-A-0 277 004 and their equivalents, U.S. Pat. Nos. 5,198,401 and 5,278,119, particularly Examples 27 and 32. Example 32 of '119 discloses the use of bis(trimethylsilylcyclopentadienyl) hafnium dimethyl as the metallocene compound. Example 27 of '401 lists dimethylsilylbis (indenyl) zirconium dimethyl in column 9, line 16.
Homogeneous processes such as high pressure, high temperature polymerization processes, such as those at 500 bar and above, have shown particular suitability with such catalyst systems since these systems exhibit greater stability than those using alumoxanes co-catalysts at 160.degree. C. and above. This allows for the greater productivity that occurs with greater reactivities at high temperature, the high pressure maintaining an essentially single phase reaction medium while permitting the higher temperatures. See U.S. Pat. No. 5,408,017 and equivalent WO-A-93/05732. A generic, broad description of suitable metallocene compounds is given as is a generic description of suitable anion precursors. The examples include the metallocene compounds dimethylsilylbis (4,5,6,7 tetrahydro-indenyl) zirconium dimethyl and dimethylsilylbis (4,5,6,7 tetrahydro-indenyl) hafnium dimethyl. The former showed significantly higher catalyst productivity (expressed as kg-PE/g-activator) in Table 2, ranging from 100 to 160, while that of the hafnium compound exhibited only 60. A similar olefin polymerization process that can be operated at high temperature and pressure is disclosed in WO 95/07941. The principal problem addressed is build up of polar material in recycle streams of the reactor, the solution is the use of bulky scavengers, e.g., those having at least one tertiary carbon atom, such as triisobutyl alumoxane. Me.sub.2 Si(Ind).sub.2 Hf Me.sub.2 is shown in Comparative Example 3 and Example 4, and said to be active longer and illustrative of high conversions.
The selection of substituents on the pi-bound, cyclopentadienyl ligands in the metallocene compounds has been identified as a means of increasing performance in olefin polymerization processes. For example, see U.S. Pat. No. 5,304,614 where specifically substituted indenyl ligands and their methods of preparation are described. Very high molecular weight polyethylene at high activity is said to be possible by use of the described metallocene compounds based on any of the group IVB, Vb or VIb metals. Zirconium and hafnium are said to be preferred and the preferred substituent structure is characterized by 1) alkylene or silylene groups bridging two cyclopentadienyl ligands bound to the metal atoms and 2) 4,7-substituted benzo groups fused on the respective sides opposite the H- or C.sub.2 to C.sub.4 2-substituent on those same cyclopentadienyl groups. Examples 14-18 are of homopolymer polyethylene using specifically substituted bis(indenyl)zirconocenes with an alumoxane co-catalyst at a temperature of 70.degree. C. and ethylene pressure of 5 bar. Productivity ranged from 35 to 56 g PE for 1 hour of polymerization reaction. The highest production was reported for Me.sub.2 Si (3,4,7-Me.sub.3 Ind).sub.3 Zr Cl.sub.2.
In EP-A1-0 612 768, bridged and unbridged hafnium metallocene compounds stabilized by non-coordinating anions after activated with alkyl-aluminum co-catalysts are said to demonstrate high catalyst activity over the zirconium analogues when utilized in processes at temperatures at or exceeding 120.degree. C. The medium pressure solution processes are preferably to be conducted at pressures of 500 to 3500 kg/cm.sup.2. All listed hafnocenes are dichloride-substituted embodiments and each of the working examples of the invention is alkylene bridged, with cyclopentadienyl, indenyl or fluorenyl pi-bound ligands.
Catalyst systems based on monocyclopentadienyl titanium compounds activated with alumoxane suitable for the preparation of ethylene-.alpha.-olefin copolymers of high molecular weight and high a-olefin content are described in U.S. Pat. No. 5,264,405. This patent teaches that the cyclopentadienyl group should be fully substituted with methyl groups and bridged to an amido group having an aliphatic or alicyclic hydrocarbyl ligand bonded through a 1.degree. or 2.degree. carbon. Copolymerization of ethylene with propylene in Example 45 with a bridged monocyclopentadienyl Group 4 metal catalyst compound at 80.degree. C. produced a copolymer with 20 wt. % ethylene having an M.sub.n of about 20,080. In each Example 55 with the same catalyst as with Example 45, at a reaction temperature of 140.degree. C., an ethylene-propylene copolymer having a density of 0.863, indicative of an amorphous ethylene copolymer, exhibited an M.sub.n of about 46,500.
Due to the sensitivities of ionic catalyst systems to polar impurities, solution polymerization processes utilizing scavenging compounds, for example alkyl aluminum compounds or alkyl alumoxanes, have been described. See, for example, U.S. Pat. Nos. 5,153,157 and 5,241,025, describing Group-IIIA metal scavenger compounds and processes. WO-A-94/07927 addresses a similar process as adapted for monocyclopentadienyl catalyst systems, it describes advantages of bulky scavengers when the monocyclopentadienyl catalyst compounds do not contain bulky substituents to impede interaction with the scavenging compounds. Triisoprenyl aluminum is exemplified and triisobutyl aluminum is listed along with tri-n-octyl and tri-n-hexyl aluminum as suitable bulky scavengers.
In view of the breadth of the disclosures concerning the use of metallocenes for olefin polymerization, and the general industrial need to employ the most effective catalysts and processes so as to have increased productivities while maintaining both comonomer incorporation and high molecular weight polymer preparation capability, additional investigative efforts were required. In particular general knowledge based on observations in the field gave rise to the traditional understanding that under temperatures exceeding about 80.degree. C. increased comonomer incorporation using metallocene catalysts resulted in lower molecular weight polymer.
Invention Disclosure
It has been discovered in resulting investigations that even when subjected to the demanding conditions of high temperature in solution and high pressure processes, high molecular weight ethylene copolymers (M.I..ltoreq.10, preferably, M.I..ltoreq.1) can be polymerized in the presence of stable, single-sited discrete ionic catalyst systems, for example, those having cations derived from the transition metal compound group consisting of 1) bridged, unsubstituted- or substituted-indenyl, or fluorenyl group containing, hafnium compounds; 2) bridged hetero-atom containing, substituted or unsubstituted monocyclopentadienyl titanium compounds; 3) unbridged, bulky Group 15 containing, bulky monocyclopentadienyl titanium compounds; 4) Group 4 or 5 compounds containing bulky chelating diamide ancillary ligands; and 5) Group 8 metal diimine compounds wherein the metal is in a +2 oxidation state, such as Pd(II) and Ni(II). Accordingly the invention is in part a process for copolymerizing ethylene and at least one higher olefin, that is C.sub.3 to C.sub.20, preferably C.sub.4 to C.sub.8, alpha-olefin, diolefin, or C.sub.4 to C.sub.20 cyclic olefin, comprising the step of contacting said monomers with one or more of the stable, single-sited ionic catalysts with a cation above and a stabilizing, compatible non-coordinating anion in a polymerization reaction with a reaction medium temperature of 90.degree. C. or above, and optionally at a pressure exceeding 50 bar, preferably exceeding 75 bar for solution processes and 500 bar for high pressure supercritical phase processes. The invention is also in part a modified process comprising the additional step of introducing into either the reaction medium, recycle stream or the monomer feedstocks prior to the polymerization reaction, a scavenger for polar impurities, most preferably a trialkyl aluminum each alkyl being a long-chain, linear-alkyl.
Detailed Description and Best Mode of the Invention
The bridged hafnium compounds of the invention include those having one or more carbon, silicon, or germanium atoms bridging two cyclopentadienyl (Cp) ligands of the hafnium metal centers, said ligands optionally containing one or more hydrocarbon substituents. When the Cp ligand is an indenyl or fluorenyl group, substitutions can be made either on the 5 or 6 member ring carbon atoms. Substituents typically include one or more C.sub.1 to C.sub.30 hydrocarbon groups selected from linear, branched, cyclic, aliphatic, aromatic or combined groups, whether in a fused-ring or pendant configuration. For the purposes of this application the term "hydrocarbon" is meant to include those compounds or groups that have essentially hydrocarbon characteristics but optionally contain not more than about 10 mol. % non-carbon, polar atoms, such as oxygen, sulfur, nitrogen and phosphorous. Similarly the use of hetero-atom containing cyclopentadienyl rings, where a non-carbon atom replaces one of the ring carbons, is considered for this specification to be within the terms "cyclopentadienyl", "indenyl", and "fluorenyl".
Specific bridged hafnium catalysts include those derived from: (1) indenyl-based complexes such as the rac- or meso-isomer of dimethylsilyl bis (indenyl)hafnium dimethyl, dimethylsilyl bis(4,5,6,7-tetrahydro-indenyl) hafnium dimethyl, dimethylsilyl bis(2-methyl-indenyl) hafnium dimethyl, dimethylsilyl bis(2-propyl-indenyl) hafnium dimethyl, dimethylsilyl bis(4-methyl, 2-phenyl-indenyl) hafnium dimethyl; (2) cyclopentadienyl complexes such as dimethylsilyl (cyclopentadienyl)(tetramethyl cyclopentadienyl) hafnium dibenzyl, dimethylsilyl bis(cyclopentadienyl) hafnium dimethyl; and (3) fluorenyl-based complexes such as dibutylsilyl (fluorenyl) (cyclopentadienyl) hafnium dimethyl and dimethylsilyl (indenyl) (fluorenyl) hafnium dihydride, or i-propyl (cyclopentadienyl) (fluorenyl) hafnium dimethyl.
In particular, for the bridged bis indenyl hafnium compounds, it has been found that increasing the degree of substitution on the indenyl ligands is effective for increased comonomer incorporation, an effect surprising in view of the general knowledge in the art. Thus when the indenyl substituents include at least two sigma bound hydrocarbon radicals replacing hydrogen atoms on the ring atoms, the performance exceeds that where either of zero substituents or just one substituent are present. For example dimethylsilyl bis(2-methyl, 4-phenyl-indenyl) hafnium dimethyl has been found to provide one or both of higher comonomer incorporation and higher molecular weight as compared to dimethylsilyl bis(2-methyl-indenyl) hafnium dimethyl, which is better in one or both of these features than dimethylsilyl bis(indenyl) hafnium dimethyl. Thus preferably the ligation on the indenyl radicals in the bulky hafnium compounds will generally comprise two or more C.sub.1 to C.sub.30 hydrocarbon substituents as defined above.
The silicon bridged hetero-atom containing, substituted or unsubstituted monocyclopentadienyl titanium compounds of the invention are any of those described in the art, see for example those described in U.S. Pat. No. 5,264,405, WO 92/00333 and U.S. Pat. No. 5,408,017. The substituted cyclopentadienyl ligand is one having hydrocarbon substituents as defined for the cyclopentadienyl, indenyl and fluorenyl ligands of the bridged hafnium compounds above. Each document in incorporated by reference for purposes of U.S. patent practice.
The unbridged, bulky Group 15 containing, bulky monocyclopentadienyl titanium compounds of the invention are unbridged titanium compounds having ancillary ligands including a substituted, bulky cyclopentadienyl ligand, a substituted, bulky Group 15 heteroatom ligand, and two uninegative, activation reactive ligands at least one of which that can be abstracted for activation of the remaining metal compound to a catalytically active state and one of which is either similarly abstractable or has a .sigma.-bond to the transition metal into which an olefin or diolefin can insert for coordination polymerization. Typically, for any of the catalysts of this invention, uninegative, activation reactive ligands are selected from the group comprising hydride, lower alkyl, e.g., C.sub.1 to C.sub.4, or silyl. The bulky cyclopentadienyl ligand is one having substituents as defined for the cyclopentadienyl, indenyl or fluorenyl ligands of the bridged hafnium compounds above, particularly lower alkyl-substituted ligands, such as tetramethyl and pentamethyl cyclopentadienyl ligands. The bulky Group 15 heteroatom ligand is typically a hydrocarbon substituted Group 15 element, preferably nitrogen, wherein the hydrocarbon substituents are covalently bound to the heteroatom through a secondary or tertiary carbon or silicon atom. See also, copending application U.S. Ser. No. 08/545,973, filed Oct. 20, 1995 (Atty. Docket No. 95B059) which is incorporated by reference for purposes of U.S. patent practice.
Ionic catalysts derived from Group IVB metal precursors where the ancillary ligand system does not contain a cyclopentadienyl ligand may also be employed in this invention. In general, these systems will be prepared from an ionic activator or Lewis Acid activator and a Group IVB metal containing precursor of the following general formula: ##STR1## wherein:
A is an optional bridging substituent,
L.sub.1 and L.sub.2 are the same or different non-Cp ancillary ligands,
M is a Group IVB metal, and
R.sub.1 and R.sub.2 are the same or different .sigma.-bonded groups such as hydride or hydrocarbyl.
An example of a suitable non-Cp ancillary ligand system is described in "Conformationally Rigid Diamide Complexes: Synthesis and Structure of Tantalum(III) Alkyne Derivatives", D. H. McConville, el al, Organometallics 1995, 14, 3154-3156. Among the Group 4 metals, the Group 4 metals are preferred especially those of titanium. The Group 4 metal compounds will additionally comprise at least two uninegative, activation reactive ligands at least one of which that can be abstracted for activation of the remaining metal compound to a catalytically active state and one of which is either similarly abstractable or has a .sigma.-bond to the transition metal into which an olefin or diolefin can insert for coordination polymerization. The Group 4 metal compounds having the described ligands can be prepared as illustrated in the Organometallics article except that the Group 5 metal halide is replaced with a Group 4 tetrahalide
The Ni.sup.2+ and Pd.sup.2+ complexes of the invention are diimine complexes that can be prepared by methods equivalent to those used for the compounds described in "New Pd(II)- and Ni(II)-Based Catalysts for Polymerization of Ethylene and .alpha.-Olefins", M. Brookhart, el al, J. Am. Chem. Soc., 1995, 117, 6414-6415. These can be either the dialkyl ether adducts as described, or alkylated reaction products of the described dihalide complexes that can be activated to a cationic state by the anion precursors according to the invention.
In general effective scavenging compounds for ionic polymerization catalysts include those aluminum alkyl compounds listed in U.S. Pat. Nos. 5,153,157 and 5,241,025. The term "scavenger" is used in its art-recognized sense of being sufficiently Lewis acidic to coordinate with polar contaminates and impurities adventiously occurring in the polymerization feedstreams or reaction medium. In particular, for processes utilizing recycle streams of unconverted monomer for reprocessing, the necessity to use polar compounds as catalyst deactivators, or "killers", such as water or lower alcohols, effectively necessitates the use of scavengers, as does the natural occurrence of polar impurities in monomer feedstreams. It has been discovered, however, that the use of excess scavenger has a deleterious effect on catalyst performance, and that the proper choice of scavenger is important to minimize the effects. Addition of excess scavenger causes lower productivity, molecular weight and comonomer incorporation. This effect can be easily seen by comparing Examples 1.2, 1.6, 1.7, and 1.8 in Table 1 of the examples section, when the addition of 6 equivalents of triethylaluminum (TEAL) caused an increase in productivity but as more TEAL was added productivity decreased as did the molecular weight and comonomer content of the product. Replacing TEAL with triisobutyl aluminum (TIBA) (Examples 1.9-1.12) improved the catalyst performance under excess scavenger conditions but did not completely remedy the situation.
Experiments under high temperature conditions showed similar trends. In order to further improve the performance of the ionic catalyst system, a systematic study of more substituted scavengers was carried out. Based on the observation that TIBA performed better than TEAL, it was expected that more highly substituted aluminum alkyl compounds, such as Al(CH.sub.2 CMe.sub.3).sub.2 Me, where Me is methyl, would be superior to TIBA because of the increase steric bulk around the Al atom. Comparative tests under high temperature conditions showed that Al(CH.sub.2 CMe.sub.3).sub.2 Me was inferior to TIBA and caused sudden loss of productivity at very low levels of scavenger. Further studies showed that the preferred scavenger is a long chain, linear tri-alkyl aluminum compound, and that longer chains are preferred over shorter chains.
Non-limiting examples of effective long chain, linear tri-alkyl ligand-containing scavengers include those comprised in the group defined by the formula M'R'R"R'", where M' is Al, and each of the R groups independently is a C.sub.4 or higher linear, branched or cyclic alkyl group, preferably C.sub.6 or higher, most preferably C.sub.8 or higher. The long chain, linear alkyl aluminums where each alkyl substituent was of a length of C.sub.8 or higher, preferably C.sub.9 and higher were observed to exhibit optimal performance, that defined as having the least deleterious effect when used at a level in excess of the optimum level as described in the following paragraph. Specifically included are: tri-n-octyl aluminum, tri-n-decyl aluminum, tri-n-dodecyl aluminum, tri-n-hexadecyl aluminum, and the higher carbon number equivalents, e.g., (C.sub.20).sub.3 Al, including those with mixed ligation, and mixed scavenger compounds as well. The hydrolyzed derivatives of these alkyl-ligand containing organoaluminum compounds will additionally be suitable. Additionally, it will be apparent that those scavenging compounds comprising both long-chain, linear and bulky ligands or mixed linear ligands, each ligand as described above, will also be suitable, but perhaps less desirable due to more involved or expensive syntheses.
The long chain, linear-alkyl ligand-containing scavengers of the foregoing paragraph will be useful in any insertion polymerization process for olefinically or acetylenically unsaturated monomers with any of the ionic catalyst systems known in the art or those in development, where such make use of non-coordinating anions and the resulting catalyst sensitivities require elimination of polar impurities. Suitable catalyst systems appear in the catalyst references listed in the Background in this application, additional catalysts include those Group 5 and 6 transition metal catalyst systems of WO 94/01471 based on U.S. Ser. No. 08/086,772 filed Jul. 1, 1993, the disclosures of which are incorporated by reference for purposes of U.S. patent practice. Examples of suitable process conditions include those of gas phase, solution, slurry or bulk polymerization processes for any polymers or copolymers of two or monomers selected from the group consisting of ethylene, propylene, C.sub.4 -C.sub.20 .alpha.-olefins, strained ring cyclic olefins, macromers of up to 100 or more mer units having olefinic unsaturation in the 1-position, or acetylenically unsaturated monomers. Such processes utilize -50.degree. C. to 300.degree. C. temperature and 0 to 3000 bar pressure. Polymers and copolymers having molecular weights equivalent to an M.I. of 100 and below can be prepared in these processes.
The scavengers, whichever are selected, should be utilized in a manner consistent with the sought productivity, polymer molecular weight, and polymer comonomer content. In particular, only that amount sufficient to neutralize the effects of the adventitious catalyst poisons should be utilized, the better purified the comonomer feedstreams into the reactor and as well the other feedstreams or added reactants and recycle, the less scavenger will be required. The amount is preferably as little as possible and can be adjusted empirically by observing the rates of reaction, adiabatic temperature rise, and other indicators of reaction efficiencies observable in the polymerization process, each being maximized holding all variables other than the addition of scavenger constant. Excess scavenger has been observed to cause a reduction in productivity, molecular weight and comonomer incorporation.
Means of preparing the ionic catalyst systems comprising cations of the described transition metal compounds and suitable non-coordinating anions are conventionally known, see for example U.S. Pat. No. 5,198,401 and WO 92/00333. Typically the methods comprise obtaining from commercial sources or synthesizing the selected transition metal compounds comprising an abstractable ligand, e.g., hydride, alkyl or silyl group, and contacting them with an ionizing non-coordinating anion source or precursor in an aromatic solvent. The anion source acts to ionize the transition metal compounds by abstracting the univalent hydride, alkyl or silyl ligand that complements its total valency. The abstraction leaves the transition metal compounds in a +1 cationic state, which is counterbalanced by the stable, compatible and bulky, non-coordinating anion. See the filler description in U.S. Pat. No. 5,198,401, referred to above. Conditions of adiabatic polymerization processes such as practiced at high pressure, result in temperatures exceeding 160.degree. C. and above. These higher operating temperatures lead to increasing instability that is reflected in more difficult higher olefin comonomer incorporation and reduced molecular weight polymer. However, the single site catalysts of this invention under those same conditions evidence higher stability, greater comonomer incorporation and higher retained molecular weight as evidenced in the tabulated observations below.
The non-coordinating anion sources of the invention includes any of those conventionally known to be useful for olefin polymerization with metallocenes, including those known to be useful with the single cyclopentadienyl containing Group 4 transition metals. A representative listing of suitable anions is in U.S. Pat. No. 5,198,401, EP-A-0 426 637, EP-A-0 427 697, EP-A-0 520 732, EP-A-0 573 403, WO 95/24268 and U.S. Pat. No. 5,387,568. Those may be introduced into the catalyst preparation step as either ionic compounds having a cation which abstracts a non-cyclopentadienyl ligand of the transition metal compounds or as neutral compounds which upon abstraction of the non-cyclopentadienyl ligand, leave as a by-product the non-coordinating anion portion. Additionally, it is known that the use of alkylating compounds along with an anion source enables the use of transition metal compounds having ligands too strongly bound to the transition metal center to be abstracted by the anion source, e.g., transition metal dihalides. Typical alkylating sources may be any of the strongly Lewis acidic organoaluminum compounds such as the lower carbon number alkyl aluminums and alkylalumoxanes. See EP-A-0 500 944, EP-A-0 570 982 and EP-A1-0 612 768 for in situ processes describing the reaction of alkyl aluminum compounds with dihalo-substituted metallocene compounds prior to or with the addition of activating anion precursor compounds. Each of the above documents is incorporated by reference for purposes of U.S. patent practice. Most preferably transition metal compounds not having halide ligands on the metal center are used for the ionic catalyst systems of this invention since in situ alkylation processes may result in competing reactions and interactions that tend to interfere with the overall polymerization efficiency under conditions of high temperature in accordance with this invention.
A class of preferred anion precursor compounds are hydrated salts comprising a Group 1 or 2 cation and a non-coordinating anion as described above. The hydrated salts can be prepared by reaction of the metal cation-non-coordinating anion salt with water, for example, by hydrolysis of the commercially available or readily synthesized LiB(pfp).sub.4 which yields Li.multidot.H.sub.2 O! B(pfp).sub.4 !, where (pfp) is penta- or perfluorophenyl. The by-product of ionization of the abstractable ligand-containing transition metal compounds with this precursor is LiOH which is non-volatile and thus is not recycled in the separation phase wherein the polymer is removed from monomer and any diluent prior to recycle. Tests have shown that this low-cost precursor operates to form ionic catalysts having properties essentially equivalent to those formed with the preferred precursor compounds represented by Ph.sub.3 C!B(pfp).sub.4 ! and PhMe.sub.2 NH!B(pfp).sub.4 !, Ph representing phenyl and Me representing methyl. As with the long chain, linear-alkyl ligand-containing scavengers noted above, this non-volatile by-product anion precursor will be suitable for use with any of the ionic catalyst systems known in the art or those in development, where such make use of non-coordinating anions. Catalytically suitable transition metal compounds capable of cationization include those Group 4 to 6 and 8 compounds addressed above. Again, examples of such include gas phase, solution, slurry and bulk polymerization processes for any polymers or copolymers of two or monomers selected from the group consisting of ethylene, propylene, C.sub.4 -C.sub.20 .alpha.-olefins, strained ring cyclic olefins, macromers of up to 100 or more mer units having olefinic unsaturation in the 1-position, or acetylenically unsaturated monomers. Such processes utilize -50.degree. C. to 300.degree. C. temperature and 0 to 3000 bar pressure.
Known alkylalumoxanes are additionally suitable as catalyst activators for the invention single-site transition metal compounds comprising halide ligands, however these are less preferred since the alumoxane activators are less temperature stable at or above about 160.degree. C. The alumoxane component includes all those useful as a catalyst activator, typically such will be an oligomeric aluminum compound represented by the general formula (R--Al--O).sub.n, which is a cyclic compound, or R(R--Al--O).sub.n AlR.sub.2, which is a linear compound. In the general alumoxane formula R is a C.sub.1 to C.sub.5 alkyl radical, for example, methyl, ethyl, propyl, butyl or pentyl and "n" is an integer from 1 to about 50. Most preferably, R is methyl and "n" is at least 4. Alumoxanes can be prepared by various procedures known in the art. For example, an aluminum alkyl may be treated with water dissolved in an inert organic solvent, or it may be contacted with a hydrated salt, such as hydrated copper sulfate suspended in an inert organic solvent, to yield an alumoxane. Generally, however prepared, the reaction of an aluminum alkyl with a limited amount of water yields a mixture of the linear and cyclic species of the alumoxane.
A preferred process of polymerization is that conducted at high pressure, that is at from 200 to 3000 bar, preferably from 500 to 2500 bar in a homogeneous single phase or two fluid phases, with or without unreactive diluents or sulvents at temperatures generally above the melting point of the polymer being produced. Such processes are typically known and may include the use of scavenger compounds and catalyst deactivation or killing steps, see for example U.S. Pat. No. 5,408,017, WO 95/07941, and WO 92/14766. Each of these documents and their U.S. counterparts are incorporated by reference for purposes of U.S. patent practice. Preferred catalyst deactivators, or killers, include high molecular weight, non-recyclable compounds, such as poly vinyl alcohol which exhibit the functional capacity to complex with the catalysts so as to deactivate them while not forming volatile polar by-products or residual unreacted compounds.
Another preferred process in which any of the catalyst, cocatalyst and scavenger selections disclosed in this application can be advantageously practiced is that of a continuous, solution process operated at or above 90.degree. C. to 120.degree. C., even above 150.degree. C. or above 160.degree. C., up to about 300.degree. C. Typically this process is conducted in an inert hydrocarbon solvent, linear, cyclic or branched aliphatic, or aromatic, at a pressure of from 20 to 200 bar. The disclosures of U.S. patent applications Ser. No. 08/426,363, filed Apr. 21, 1995, and Ser. No. 08/545,973 (Atty. Docket 95B059), filed Oct. 20, 1995, provide relevant description, even when operated at the elevated temperature ranges under supercritical conditions disclosed in this application. These documents also are incorporated by reference for purposes of U.S. patent practice.
For optimal polymerization results the processes should be designed or conducted such that the cocatalyst components, that is the transition metal compounds and the anion precursor compounds, are maintained separately until just prior to or during polymerization use in the chosen reactor. An example is the use of dual injection of each catalyst component directly into the reactor or the use of T- or multi-joint mixing chambers just prior to injection into the reactor. Alternatively the catalyst may be formed in-situ by the independent addition of ionic activator, ligand stabilized metal halide, and scavenger directly into the reactor or the use of T- or multi-joint mixing chambers just prior to injection into the reactor. Additional optimization can be achieved when the scavenger compound is introduced into the reactor independently of the catalyst system, or compounds.
Though directed specifically for high temperature, particularly high pressure or solution, processes, it will be apparent that the use of heterogeneous support material such as polymeric and metal or metalloid oxide supports will enable slurry or gas phase use of the process steps and components described and will likely achieve similar benefits of higher productivities, higher molecular weights, and higher levels of comonomer incorporation for the ethylene copolymer products capable of production using the disclosed copolymerizable monomers. Illustrative support methods appear in WO 91/09882, WO 94/00500, WO 94/03506, WO 94/07928, and in WO 96/04319 based on U.S. application Ser. No. 08/474,948 filed Jun. 7, 1995, in turn based on U.S. Ser. No. 08/285,380 filed Aug. 3, 1994. A suitable slurry process is described in U.S. Pat. No. 5,229,478. Each of the foregoing are incorporated by reference for purposes of U.S. patent practice.
The following examples are presented to illustrate the foregoing discussion. All parts, proportions and percentages are by weight unless otherwise indicated. Although the examples may be directed to certain embodiments of the present invention, they are not to be viewed as limiting the invention in any specific respect. Methods of determining MW and monomer contents by GPC and NMR for the illustrative EPC examples of the invention are described in U.S. Pat. No. 5,229,478 which is incorporated by reference for purposes of U.S. patent practice. For the following examples certain abbreviations have been utilized for convenience: Cp (cyclopentadienyl), Me(methyl), Ind (indenyl), Ph (phenyl), pfp (pentafluorophenyl), r-(racemic), Et (ethyl), Cp* (permethylated cyclopentadienyl), Cod (cyclododecyl), TOA (tri-n-octyl aluminum), TEAL (triethyl aluminum) and TIBA (triisobutyl aluminum).

High temperature olefin polymerization process


A waffle maker having a base and a waffle mold supported by the base. The waffle mold has a first heating plate and a second heating plate, wherein the second heating plate is movable with respect to the first heating plate. A first heating element is arranged on the waffle mold for heating the first and second heating plates. The waffle maker further includes a sensor configured to detect motion in a detection area. A control unit of the waffle maker is in communication with the sensor and the first heating element, such that when the presence of a human is detected in the detection area, the control unit heats the first heating element to a predetermined pre-heat temperature.

Various appliances for preparing food or beverages include at least one heating element that is used to heat or cook the food or beverage. Examples of such appliances include waffle makers, toasters, heating trays, electric kettles, panini presses, and electric grills or griddles, among others. The appliances may be used as consumer products in a household and may be kitchen appliances, or the appliances may be used in a commercial setting, such as in a restaurant, bar or the like. In order to quickly prepare food, it can be useful to pre-heat the appliance prior to the time the appliance is used to prepare food. However, if the heating element is active even when the appliance is not being used to prepare food, the appliance may consume a considerable amount of electricity and the useful life of the appliance may be reduced.
Accordingly, there is a need in the art for appliances having heating elements for preparing food that operate efficiently to allow for pre-heating of the appliance without wasting electricity.

System and method for operating a heating element of an appliance


A technique for coordinating the operation of subscriber units such as in a wireless communications system so that high-probability-of-interference communications do not take place at the same time in adjacent cell sites. A base station becomes aware of expected periods or time slots of high relatively expected interference from remote units operating in a neighboring cell site, and then schedules only low interference level transmissions for its own remote units during such periods. Expected interference information can be exchanged by base stations directly, through a centralized base station controller-initiated schedule, or by relaying resource load status messages via remote units located near all boundaries.

The so-called near-far problem is well documented in certain wireless communications systems, such as cellular telephone systems. This problem is an artifact of a point-to-multipoint architecture wherein base stations are located in cells. In this architecture, each base station services a number of subscriber units, such as portable handsets, located throughout a cell. The remote subscriber units may be located at various distances from the base station within the cell, and may even be mobile within a cell or between cells.
It becomes desirable in such systems, and in particular, those making use of Code Division Multiple Access (CDMA) type modulation, for precise control over the power levels of the transmitted signals. This is in particular important for reverse link signals, that is, the signals traveling from the subscriber units towards the base station. It is desirable for these signals to all arrive at the base station with approximately the same power level, although they may have to travel over various distances. This is advisable in general for a point-to-multipoint system, but particularly important where CDMA codes are used, because the mathematical premise behind the correct functionality of CDMA coded signals assumes that all transmitters are operating at the same power level. The most widely used approach to solving this problem is for the base station to precisely control the transmit power level at each originating subscriber unit. However, even with precise power level control, subscriber units located in outlying areas of the cell must transmit at higher power levels than do the units located closer in to the base station. The so-called near-far problem thus originates from the fact that the high power transmissions from units located at the outlying areas of the edges of the cell may interfere with the operation of the lower power units closer into the base station.
Of course in a cellular system there are typically many cells each of which are adjacent to other cells and which may have overlapping areas of coverage of other cells. In such a system, mobile units located at the far edges of the cell operating at high power may not only interfere with units located in their own cell, but also with other mobile units located in the adjacent cell. Thus an uncoordinated transmission originating from such a mobile unit operating at high power on the edge of the cell may not only degrade the performance of other units within its own cell, but also affect the performance of other mobile units located in adjacent cells as well.
While this can be tolerated to some extent in analog systems, for CDMA systems, this not only results in interfering with individual communications between individual mobile units and the base station but may also affect the available capacity of the entire adjacent cell. In other words, in CDMA systems, interference between the operation of different mobile units causes degradation in the performance of other units to the extent that the available data rates are reduced. That is, the codes used in a code division multiple access system are based upon a mathematical premise that the individual signals arrive at the receiver with approximately the same power levels. If the signals do not arrive with equal power, errors will occur in the decoding process.

Queuing far/far service requests in wireless network


An apparatus is described for forwarding data in a data communications network having as components nodes and links therebetween in which nodes obtain a reachability metric between a neighbor node and one or more other nodes in the network and in which a repair path is created between an instigating repair node and a receiving repair node around a failure component therebetween. A propagatable repair address for the receiving repair node is reachable by the repair path notvia the failure component. The apparatus is arranged to treat propagatability of the repair address differently via the failure component than via other components.

The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In computer networks such as the Internet, packets of data are sent from a source to a destination via a network of elements including links (communication paths such as telephone or optical lines) and nodes (for example, routers directing the packet along one or more of a plurality of links connected to it) according to one of various routing protocols.
One class of routing protocol comprises Routing Vector Protocols according to which the path to a network destination is determined based on a reachability metric. One such protocol comprises a distance vector protocol such as the Routing Information Protocol (RIP) which is described in Internet Engineering Task Force (ietf) request for comments (RFC) 1058 and 1723.
A problem that arises with routing vector protocols such as RIP is that if a component fails in the network then packets may be lost while the network converges on a changed topology. For example if node A fails then according to normal forwarding, until node B has updated its forwarding information base, it will forward packets for nodes A and D to node A and those packets will be lost.

This patent is subject to a terminal disclaimer.

Forwarding data in a data communications network


A shoe having improved stability and cushioning by incorporating aspects similar to certain structures of the human foot. The shoe includes a shoe sole having a contour similar to that of the human foot, including a sole inner surface and a sole outer surface each having concavely rounded portions. The shoe sole further includes a compartment or compartments to provide cushioning similar to the fat pads of the human foot. The compartment or compartments include a pressure transmitting medium, such as a gas, gel or liquid. The shoe may also include a shoe upper enveloping at least a part of the shoe sole to provide stability similar to that provided by the outer surface of the human foot.

This invention relates generally to the structure of footwear. More specifically, this invention relates to the structure of athletic shoe soles that copy features of the underlying support, stability and cushioning structures of the human foot. For example, this invention relates to support and cushioning which is provided by shoe sole compartments filled with a pressure-transmitting medium like liquid, gas, or gel. The pressure-transmitting medium provides cushioning progressively, thereby causing tension in flexible and relatively inelastic sides of a shoe sole. These compartments of the shoe sole provide support and cushioning similar in structure to the fat pads of the natural human foot, which simultaneously provide both firm support and progressive cushioning.
Existing cushioning systems cannot provide both firm support and progressive cushioning without also obstructing the natural pronation and supination motion of the foot. This is because the overall concept on which existing shoe cushioning systems are based is inherently flawed. For example, existing shoe cushioning systems do not provide adequate control of foot motion or stability. Conventional systems are generally augmented with rigid structures on the sides of the shoe uppers and the shoe soles, like heel counters and motion control devices, in order to provide control and stability. Unfortunately, these rigid structures seriously obstruct natural pronation and supination motion and actually increase lateral instability.
In marked contrast to the rigid-sided designs, the human foot provide stability at it sides by putting those sides, which are flexible and relatively inelastic, under extreme tension. The tension is caused by the pressure of compressed fat pads, wherein the fat pads become temporarily rigid when outside forces make that rigidity appropriate, thereby producing none of the destabilizing lever arm torque problems of the permanently rigid sides of existing shoe sole designs.
Among other objects, this invention attempts, as closely as possible, to replicate features of the naturally effective structures of the human foot that provide stability, support, and cushioning.
This and other objects of the invention will become apparent from a detailed description of the invention which follows taken with the accompanying drawings.


A method for detecting the presence or absence of pathogenic. STEC in food samples includes                incubating the food sample in a culture medium to obtain an E. coli stock medium;        lysing the E. coli to obtain a E. coli DNA; and        subjecting the DNA to PCR, and amplifying the following genes or fragments thereof:                    stx1 and/or stx2 encoding Shiga toxin 1 and Shiga toxin 2,            for each STEC serogroup to be determined, the subtype of the eae gene of that serogroup encoding an intimin, and            for each STEC serogroup to be determined, a biomarker gene specific for that serogroup;and, if stx1 and/or stx2 and the eae gene and the specific biomarker gene for at least one serogroup are amplified in the PCRs:                        verifying the presence of the one or more specific serogroups of STEC by PCRs on concentrates of the E. coil stock medium.

Among the strains of STEC, seven serogroups, i.e., O157, O26, O45, O103, O111, O121, and O145, have been identified to be associated with severe illness in humans. These serogroups are referred to in the following as STEC Top7. The United States Department of Agriculture (USDA) has implemented regulations applicable to the analysis of certain raw beef products which define in addition to the serogroup O157 six further serogroups as identified above as adulterants.
When determining the presence or absence of these strains of STEC, typically a food sample is added to a culture medium enabling growth of E. coli to provide an E. coli stock medium.
Subsequently, lysis of the E. coli in the stock medium provides for a sample solution comprising E. coli DNA.
The subsequent detection of the above-mentioned serogroups in the samples in a reliable manner using conventional methods is a time consuming procedure.
The use of polymerase chain reaction (PCR) for detecting the major STEC virulence genes stx1, stx2, eae, and serogroup-specific genes is set out in the ISO 13136 technical specification (ISO/TS 13136:2012). PCR positive samples have to be confirmed by cultural methods as the different genes could belong to different strains, leading to false positive results.

Method for determining the presence or absence of shiga toxin-producing


A motion guide device includes a plurality of rolling element guide members provided along the entire length of a rolling element rolling surface so as to guide the unloaded side of a plurality of rolling elements that perform a rolling movement under load between the rolling element rolling surface and a loaded rolling element rolling surface. The rolling element guide member includes a beam member an outer member including a rolling element guide surface for guiding the unloaded side of the rolling elements, and the beam member and the outer member are insert-molded. Such a structure provides the motion guide device including the rolling element guide member that enables low cost manufacturing of a complex shape and capability of secure installation and guidance of the rolling elements with no deflection and can be adapted for use in various types by optionally selecting a connecting means.

A motion guide device, which is a mechanical element for guiding linear movement or curvilinear movement of a moving body such as a table and in which rolling elements such as rollers are interposed between guide portions, provides a smooth movement so that the motion guide device is used in various fields such as robots, machine tools, semiconductor and LCD manufacturing equipment, and medical equipment.
A linear guide, which is a type of motion guide device, includes a track rail mounted on a base and a moving block which is assembled to the track rail so as to be movable relative to one another and on which a moving body is mounted. The track rail is provided with a rolling element rolling surface extending in a longitudinal direction. The moving block is provided with a loaded rolling element rolling surface opposing the rolling element rolling surface and a rolling element circulation path for circulating rolling elements. The rolling elements are rollably interposed between the rolling element rolling surface of the track rail and the loaded rolling element rolling surface of the moving block. When the moving block moves linearly relative to the track rail, the rolling elements interposed between the track rail and the moving block perform a rolling movement and endlessly circulate through the rolling element circulation path.
In such a motion guide device, the rolling elements that endlessly circulate in line in the rolling element circulation path are required to perform a smooth rolling movement. This is because if the rolling elements do not endlessly circulate in an aligned state, for example if skew occurs in which the rolling element is inclined with respect to the normal axis of rotation, high-accuracy guiding movement is inhibited by causing wear on the rolling element and the rolling surface, for example, and this results in a short life. Accordingly, a conventional motion guide device is provided with a rolling element guide member along the entire length of a loaded rolling element rolling surface so as to guide the unloaded side of rolling elements that perform a rolling movement under load between a rolling element rolling surface and a loaded rolling element rolling surface. The rolling element guide member used in the conventional motion guide device is disclosed as a "guide member" in the following Patent Literature 1.


A method for handling Proximity-based Service (ProSe) discovery, comprising: performing a ProSe communication preparation procedure, in response to a received ProSe discovery request message, with a first UE and a second UE, for guiding ProSe discovery between the first UE and the second UE, wherein the received ProSe discovery request message indicates ProSe identifiers of the first UE and the second UE for ProSe communication and the ProSe communication preparation procedure comprises transmitting a first request message including scheduled information for the first UE and a second request message including scheduled information for the second UE, to the first UE and to the second UE respectively, and receiving response messages from the first and second UE; determining if a direct radio link between the first UE and the second UE is feasible for ProSe communication based on the received response messages from the first and second UE.

In a typical mobile communications environment, a user equipment (UE) device such as a mobile phone (also known as a cellular or cell phone), a laptop computer with wireless communications capability, or a personal digital assistant (PDA), may communicate voice and/or data signals with one or more service networks. The wireless communications between the UE and the service networks may be in compliance with various wireless technologies. A long-term evolution (LTE) system, initiated by the third generation partnership project (3GPP), is now being regarded as a new radio interface and radio network architecture that provides a high data rate, low latency, packet optimization, and improved system capacity and coverage. An evolution of core network with non-radio access aspects, known as System Architecture Evolution (SAE), is also initiated by 3GPP in accompanying with LTE.
Evolved Packet System (EPS) is a purely IP based network, consisting of user equipments (UEs), a LTE radio access network known as Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and a SAE core network known as Evolved Packet Core (EPC). The EPS uses the concept of "EPS bearers" to route IP traffic from a gateway in external packet data networks to the UE. A bearer is an IP packet flow with a specific Quality of Service (QoS) between the gateway and the UE. The E-UTRAN is simply a network of plurality of evolved Node-Bs (eNBs) communicating with a plurality of UEs, which generate a flat architecture and there is no centralized controller. The eNBs are normally inter-connected via the X2-interface and towards the EPC by the S1-interface. The EPC includes a mobility management entity (MME), a Home Subscriber Server (HSS), a serving gateway (SGW), a packet data network gateway (PDN GW or PGW). The MME deals with the control plane. It handles the signalling related to mobility and security for E-UTRAN access. The MME is responsible for the tracking and the paging of UE in idle-mode. It is the termination point of the Non-Access Stratum (NAS). The MME handles bearer management and connection management. The HSS is a database that contains user-related and subscriber-related information. The HSS also provides support functions in mobility management, call and session setup, user authentication and access authorization. The Serving GW is the point of interconnect between the radio-side and the EPC, and it serves the UE by routing the incoming and outgoing IP packets. The PDN GW is the point of interconnect between the EPC and external IP networks called PDN (Packet Data Network), and it routes packets to and from the PDNs.
A long term evolution-advanced (LTE-A) system, as its name implies, is an evolution of the LTE system and has a similar network structure to the LTE system.
In LTE-related systems, Proximity-based Service (ProSe) communication has been developed as a technology which allows UEs to communicate directly with each other in close proximity without transmitting/receiving data and/or control signals to the other via an eNB, which means a local or direct path can be used between the UEs. Therefore, in the 3GPP LTE spectrum, the operator can move the data path (i.e., user plane) off the access to core networks to direct links between the UEs.
Regarding proximity discovery procedures, it is still not clear how the network conducts proximity discovery for two UEs located in proximity and determines to set up proximity communication for two UEs within E-UTRAN coverage.
In addition, some problems may be encountered while performing the proximity discovery procedures in the wireless communications system. For example, power consumption on channels due to a lack of E-UTRAN coordination between two ProSe-enabled UEs, radio link quality for reducing UE's power consumption between two ProSe-enabled UEs in the proximity, potential interference caused by other general UEs in the proximity, delay time resulting from fine tracking on UEs' geographical locations, which may require the ProSe-enabled UEs to report location information for aiding the accuracy of the estimated locations, and so on. As a result, a method for implementing proximity-based service (ProSe) discovery and communication that may solve these problems is required.

Method for handling proximity-based service discovery and communication in a wireless communications system


Systems and methods for speed estimation based on stride data using predictive modeling relate to portable wireless devices (202) that contain GPS or other location resources to generate position and speed data. The device (202) also incorporates an accelerometer (212) or other motion sensor. When GPS signals are interrupted, an estimation module (216) and associated logic generates a speed estimate based solely on stride frequency data from the accelerometer (212). Unlike conventional estimators, the estimation module (216) operates on a non-deterministic basis, generating an estimated speed using a joint probability distribution derived from previous speed and stride data captured while positioning signals are available. The estimation module (216) can continue to operate when GPS signals are available, and either filter the GPS speed measures for spurious signals, or further train the estimation module (216) with new position data. The estimation module (216) can also incorporate altitude measurements when estimating speed.

In competitive running and other personal recreational applications, portable electronic devices may track the location and speed of a user wearing or carrying the device. In conventional devices of this type, the user's speed while running or performing other activities can often be tracked using positioning platforms, including global positioning satellite (GPS) tracking systems, by dividing elapsed distance by elapsed time. Sometimes, however, signals from GPS satellites can be obscured by trees, buildings, weather, and other obstructions. When GPS signals are corrupted or unavailable, the user will often find it convenient to continue to receive an indication of speed using alternative techniques.
An alternative technique that provides a speed value for a runner or other user detects the stride frequency of that user's walking or running pace. It has been known to use an accelerometer built into a portable electronic device to detect the comparatively sharp acceleration at the start of the user's forward stride. By tracking successive strides, the user's stride frequency can be determined.
In known platforms, the stride frequency can be used as an input to a linear, polynomial, or other deterministic model to generate an estimated current speed of the user's walking or running activity. In known estimators of this kind, the device assumes that the user's speed is related to the frequency of their detected strides in a deterministic or closed-form fashion. Sometimes there are different deterministic models for a walking user and a running user. The deterministic models can be based on human biomechanical models or other calculations which assume a direct correspondence between the stride frequency observed for the user and the user's immediate speed at that stride frequency.
However, empirical use of known speed estimator devices has shown that the estimated speed output obtained from these types of deterministic algorithms does not always match up well with actual speed. A user's estimated speed using deterministic models can differ by forty percent or more when compared to the speed as measured by accurate GPS reception.
There is an opportunity to develop methods and systems for speed estimation, in which an estimation of a user's speed while running or performing other activities can be generated with comparatively high accuracy even when GPS or other location services are not available.


Content to be presented on a ticker of a communication device is conveyed by being transmitted using one or more transmission modes that are intelligently selected according to various criteria. The mode is chosen from among a plurality of transmission modes available, such as Bluetooth, WiFi, WiMAX or other 802.11 wireless networks; AM or FM radio waves; paging networks; paging channels on cellular or PCS networks; SMS transmissions; and vertical blanking interrupts on TV transmissions. Selection of the transmission mode is based in part upon at least one consideration, such as: content size, type or subject matter; user preferences; location of the communication device; available bandwidth; current network loads; time of day; the number of other users receiving the same content, and; transmission cost. Once the mode is selected, content is transmitted to the communication device and presented in a ticker of the device.

1. Field of the Invention
The present invention relates generally to communications systems, methods and devices. More particularly, exemplary embodiments of the invention concern systems and methods directed to selecting the optimal mode or modes to transmit data to the ticker of a communication device.
2. Related Technology
The popularity of the Internet has given rise to a consumer demand for uninterrupted access to information. To accommodate the consumer demand, a plethora of information services have been developed to cater to consumers accustomed to accessing timely, personalized news and information. An example of an information service developed to cater to consumer desire for access to news and information is scrolling information displays. Scrolling information displays, referred to herein as "tickers," are one type of content display mechanism that can give a viewer a quick, high-level update of news and information. Therefore, tickers have become commonplace on television news and sports programs, providing viewers with "at-a-glance" headlines, breaking news, weather reports, sports scores and other updates.
Not only do tickers provide at-a-glance updates during television programs, tickers also serve as information displays on computers and other electronic devices. One early example of a ticker on a personal computer (PC) system is the ticker provided by Pointcast. Through the Pointcast service, PC users could subscribe to news and information channels of interest and receive periodic updates on their computer displays, often in the form of a scrolling information display at the bottom of the user's display screen. An even earlier example of the use of tickers in conjunction with a PC was the ticker provided by gaming company Catapult Entertainment, Inc. In addition to providing users with gaming-related information, the Catapult ticker was also interactive through the use of the computer mouse. Rather than being limited to the information in the ticker, the user could use the mouse to click on an item in the ticker having a Universal Resource Identifier (URI) associated with the item, which would then cause a web page to be displayed with additional information about that item.
More recently, through the use of messaging systems with near-universal reach such as the Short Message Service (SMS), mobile workers can now receive up-to-the-minute business, financial and customer information on their mobile devices. Ticker information is supplied through various news and entertainment content providers and from other information sources, including corporate portals and customer relationship management applications. Furthermore, tickers are beginning to appear as a method for dynamic information display on mobile communication devices, such as cellular telephones, personal digital assistants (PDAs), and "smart" phones.
While the value of receiving personalized, timely information in a condensed, quickly-read format such as a ticker is indisputable, the information tickers known in the art could be significantly improved. One area for improvement concerns data transmission modes. Currently, content can be transmitted to a communication device using any of a number of data transmission modes, including, but not limited to, cellular networks, internet protocol (IP) networks such as the Internet, the Short Message Service (SMS), satellite and terrestrial radio broadcasts, the 802.11 family of wireless local area networks, and Bluetooth networks.
Since it is likely that providers will transmit content of varying sizes and data types via numerous delivery mechanisms in order to deliver content to a device and populate its ticker, it would be valuable to both the communication device user and to the content provider to be able to selectively transmit content over multiple data transmission modes. In exemplary embodiments of the invention, optimal data transmission modes can be selected based on the characteristics of the content to be transmitted and other considerations, such as network traffic loads. Selectively transmitting content for display on a ticker over multiple data transmission modes would improve efficiency in transmitting data; while at the same time allow content providers and communication device users greater flexibility in transmitting data. Greater flexibility and efficiency in data transmission would also enhance user accessibility to content.

Systems and methods for populating a ticker using multiple data transmission modes