The present provides for consistent resolution of data conflicts when synchronizing data between two or more devices in order to reduce the likelihood of an infinite synchronization loop within a distributed computing system. More particularly, example embodiments provide for a conflict resolution algorithm capable of generating unique values for properties that are in conflict. Data selection criteria can then be used to determine which of the properties should be used to resolve the conflict. Such data selection criterion increases the likelihood of providing consistent resolution of similar data conflicts between other devices in the distributed system.

1. The Field of the Invention
The present invention generally relates to synchronizing data within a distributed computer system. More particularly, the present invention provides for consistent resolution of data conflicts when synchronizing data between two or more devices in order to reduce the likelihood of an infinite synchronization loop.
2. Background and Related Art
Laptop, handheld, and other portable computers or computing devices have increased in popularity as the devices become smaller in size and less expensive. Additionally, improved operating speed and processing power of portable computers has increased their popularity. Many portable computers are capable of storing multiple application programs, such as address books, games, calculators, and the like. The application programs can be permanently installed in the portable computer during manufacture (e.g., on Read-Only Memory (ROM)). Alternatively, one or more application programs may be installed by the user after purchasing the portable computer.
With the increased popularity and computing power of such devices, people are beginning to store data and applications using more than just a single computing device. Many people, for example, often use laptop computers in addition to their regular desktop computer. Other devices such as cellular telephones, Personal Digital Assistance (PDAs), Internet services, and the like are also used for storing data and applications.
Each of these computing devices may be part of a distributed computing system wherein related information can be correlated and stored on multiple such devices. For example, a user may have a digital address book stored on their desktop work computer, on their PDA, on their cell phone, on an Internet service, etc. Accordingly, while at work, it may be convenient for the user to access contact information, which may include phone numbers and other general contact information. While away from work, however, the user may be able to use the address book in a mobile form such as a personal digital assistance (PDA) or other mobile information storage system. Ideally, the contact information of the PDA should match the contact information at the desktop work computer.
When the same or related information is stored in two places, it is possible for the data to change in one location and not in the other. This problem may be overcome through synchronization, which is an automated process that attempts to ensure that each device within the distributed system has the most current information or data. Synchronization, however, has its own set of problems. For example, when synchronization is initialized between the two devices, current systems detect changed property values by comparing corresponding property values from each device. Such comparison, however, gives no indication as to which device made the change. As such, when a property change has occurred on either device, a conflict occurs and a conflict resolution process must be performed.
Other systems mark a changed property with a tag indicating that a change has occurred, e.g., "change," "delete," "add," or other tag, as appropriate. In such systems, however, when two devices start syncing, one of the devices can create these markers in memory after comparing the data for what needs to be applied. In other words, conflicts must first be reconciled and then the properties can be marked.
Typically, conflicts can be resolved through comparing metadata associated with the property values that give, e.g., time date information. The latest time date information may be considered the most up-to-date information and the properties can be updated accordingly. Many smaller computing devices, however, have limited physical resources and are incapable of maintaining time date information for properties of a data structure item. Further, in a distributing computing network there is typically no single server with a "master" copy of data that can be used to resolve discrepancies or conflicts. Accordingly, in such situations, typically a User Interface (UI) is presented to a user notifying them of the conflict and directing them to choose what value to use to resolve the conflict. This process can become, however, tedious in the event of numerous conflicts and can degrade the user experience.
Some systems have attempted to overcome the above problem by presenting a default value to the user or to resolve the conflict automatically. In either event, the choice is typically based on arbitrary techniques and considerations such as network topology. For example, some systems choose a default value or resolve the conflict through rules that choose the values based on a particular nodes status (e.g., location) within the network. For instance, one rule for resolving conflicts may mandate that if a conflict exits, all servers values should win, or if the choose is between a high fidelity and low fidelity device, then all high fidelity device values should be chosen. Of course, there are a number of network topology choices or other similar choices available.
Although selecting a value based on network topology resolves the conflict, this can also result in values being essentially continuously transferred between nodes in the distributed computing system, which is termed an infinite loop. In such situations, the user can be continually presented with choices of opposing default values to resolve the conflict and/or the data is continually updated on the devices and the user will have to provide some type of intervention in order to stop the changing of the data. Further, continuously transferring data between nodes in a distributed system unnecessarily consumes network bandwidth, preventing other modules from utilizing the network bandwidth. As such, it is desirable to be able to break infinite loops in a distributed network system in order to ensure a good user experience and preserve valuable processing resources.

Methods and systems for halting synchronization loops in a distributed system


A current steering circuit includes a first current steering pair of differentially coupled transconductance devices for current steering an input current signal to an output of the current steering circuit. A linearizer circuit includes a second pair of differentially coupled devices coupled electrically in parallel with the first current steering pair so that any current steering which takes place in the second pair is mirrored by the first pair. The linearizer circuit controls the second differential pair so that the current through the devices of the second differential pair that are coupled to the output device of the first current steering pair is exponentially dependent on the differential input voltage.

1. Field of the Invention
The invention relates generally to current steering circuits for variable gain amplifiers ("VGA's"). More particularly, the invention provides a circuit which improves the linearity (in the dB scale) of the output of a current steering circuit.
2. Description of the Prior Art
VGA's are used in numerous electronic products such as global positioning (GPS) receivers, wireless local area networks and mobile communication devices, such as cordless and cellular phones. In particular, VGA's are used in various parts of such devices, for example, in the radio frequency (RF), intermediate frequency (IF) and the low frequency, or baseband circuits, of these devices.
FIG. 1 illustrates a prior art variable gain amplifier current steering circuit 100 having a differential pair (bipolar transistors Q1, Q2) which steers a portion of an input current signal "I.sub.signal " received at input 102 to the output terminal 104, while the other, unused, portion of the input current signal is directed to ground. The amount of signal current that gets steered to the output depends on the differential control voltage "V.sub.agc " applied to the bases of the transistors Q1, Q2 via the inputs 101, 102. The portion of the input signal current that flows through the transistor Q2 appears at the output terminal, while the remainder flows through the transistor Q1 to ground. In general, applying a higher control voltage to the base of the transistor Q2, as compared to the base of the transistor Q1, will allow a larger portion of the input signal current to be available at the output 104.
The formula for the gain control characteristic of the circuit 100 results from the translinear equations of the circuit loop closed by the base-emitter junction of the transistor Q1, the base-emitter junction of the transistor Q2 and the control voltage V.sub.agc present between the input terminals 101 and 102. The resulting expression is ##EQU1## where I.sub.c1 and I.sub.c2 are the collector currents of transistors Q1 and Q2, respectively, and V.sub.T is the thermal voltage, 26 mV at room temperature. Since I.sub.c1 +I.sub.c2 =I.sub.signal (disregarding the base currents), the gain control expression which follows from Eq. 1 is ##EQU2## For gain control voltages V.sub.agc that are much smaller than 0, Eq. 3 shows a nice control characteristic in which the gain of the current steering circuit 100 is exponentially dependent on the control voltage. ##EQU3## This exponential relationship is commonly referred to as linear-in-dB, since plotted on a dB scale Eq. 3 yields a straight line in a region where V.sub.agc <<0. Unfortunately, going to higher voltages for V.sub.agc, the linear-in-dB relationship of Eq. 2 does not hold anymore. At control voltages of about 0 volts and higher, the gain control curve starts flattening out and approaches unity gain.
The current steering circuit of FIG. 1 and the above analysis (equations 1-3) are known from the text: B. Gilbert, Current-Mode Circuits from a Translinear Viewpoint: a Tutorial, at Chapter 2 (United Kingdom 1990).
The non-linearity of the control characteristic (on a dB-scale) as the control voltage approaches and exceeds zero volts is an important drawback of the circuit for use in variable gain amplifier (VGA) applications, because it decreases sensitivity of the signal gain to control voltage variations at high gain settings.
Accordingly, it is an object of the invention to improve the linearity (in the dB scale ) of the output of a variable gain amplifier.

Current steering variable gain amplifier with linearizer

Philips Electronics North America Corporation


A process for preparing polyolefins by polymerizing or coploymerizing an olefin or olefins in the presence of a catalyst comprising a solid catalyst component and an organometallic compound is provided.

The present invention relates to a process for preparing novel polyolefins. More particularly, the present invention is concerned with a process for preparing polyolefins of good particles having a large average particle diameter and a narrow molecular weight distribution, which process is capable of greatly increasing the polymer yield per solid and that per transition metal, thereby permitting the omission of the step of removing catalyst remaining in the resulting polymer, further capable of increasing the bulk density of the polymer and decreasing a fine particulate portion of the polymer.
Heretofore, in this technical field there have been known many catalysts comprising inorganic magnesium solids as carriers such as magnesium halide, magnesium oxide and magnesium hydroxide and a transition metal compound such as a titanium compound or a vanadium compound supported on the carriers. However, the polyolefins obtained in the prior art are generally low in bulk density, relatively small in average particle diameter and generally wide in particle size distribution so contain a large proportion of fine particles. Besides, when these powdery polymers are subjected to forming, there arise problems such as dusting and lowering of the forming, efficiency. For the reason, improvement has keenly been desired from the standpoint of productivity and polymer handling. Further, still further improvements are considered necessary in order to satisfy the recent keen desire for omitting the pelletizing step and using a powdery polymer directly in a processing machine.
The present inventors have previously found out a novel catalyst component with the above drawbacks remedied and already filed patent applications thereon (see Japanese Patent Publication Nos. 11651/1989 and 12289/1989 and Japanese Patent Laid Open Nos. 149605/1985, 32105/1987 and 207306/1987). The use of this catalyst component can afford a polymer having a high bulk density and a large average particle diameter. However, a further improvement has been considered necessary for omitting the pelletizing step and using a powdery polymer directly in a processing machine.
The present inventors have also proposed a catalyst capable of affording a polymer having a narrow molecular weight distribution and a reduced proportion of low molecular weight components, which is required particularly in the film field (see Japanese Patent Application No. 200348/1989). However, this polymer still cannot be considered satisfactory.
Having made extensive studies for the purpose of remedying such drawbacks and obtaining in an extremely high activity a polymer having a high bulk density, a narrow particle size distribution, an extremely small proportion of fine particles and a narrow molecular weight distribution, the present inventors accomplished the present invention.
More specifically, the present invention resides in a process for preparing a polyolefin by polymerizing or copolymerizing an olefin or olefins in the presence of a catalyst comprising a solid catalyst component and an organometallic compound, the solid catalyst component being prepared by the reaction of the following components [I], [II] and [III]:
[I] a reaction product obtained by the following components (1), (2) and (3) in the presence of a compound represented by the general formula R2OH wherein R2 is a hydrocarbon radical having 1 to 20 carbon atoms or an organic residue containing such an element as oxygen, nitrogen, sulfur, or chlorine:
(1) a silicon oxide and/or an aluminum oxide;
(2) a reaction product obtained by reacting a magnesium halide and a compound represented by the general formula [Me(OR)nXz-n] wherein Me represents an element of Groups I to IV in the Periodic Table, z represents the valence of the element Me, n is 0 less than nxe2x89xa6z, X is a halogen atom, and R is a hydrocarbon residue having 1 to 20 carbon atoms; and
(3) a titanium compound represented by the general formula Ti(OR1)mX4-m wherein R1 is a hydrocarbon radical having 1 to 20 carbon atoms, X is a halogen atom, and m is 0xe2x89xa6mxe2x89xa64;
[II] an organoaluminum compound represented by the general formula Al(OR3)pR4qX3-(p+q) wherein R3 and R4, which may be the same or different, are each a hydrocarbon residue having 1 to 24 carbon atoms, X is a halogen atom or hydrogen atom, and p and q are 0xe2x89xa6p less than 3, and 0xe2x89xa6qxe2x89xa63, provided 0 less than p+qxe2x89xa63; and
[III] a silicon compound represented by the general formula [R5aR6bR7cSi(OR8)dX4-(a+b+c+d)] where R5, R6, R7 and R8, which may be the same or different, are each a hydrocarbon residue having 1 to 20 carbon atoms, X is a halogen atom, and a, b, c and d are 0xe2x89xa6a less than 4, 0xe2x89xa6b less than 4, 0xe2x89xa6c less than 4 and 0 less than dxe2x89xa64, provided 0 less than a+b+c+dxe2x89xa64.
By the process of the present invention there is obtained, in extremely high activity, a polyolefin having a relatively large average particle diameter, a narrow particle size distribution, a reduced proportion of fine particles and a narrow molecular weight distribution. Besides, the bulk density and free fluidity of the polyolefin are high. These characteristics are very advantageous to the polymerization operation.
Further, the polyolefin prepared by the process of the present invention can be subjected to forming not only as pellets but also in the form of powder, without causing any trouble.
It is also a characteristic feature of the present invention that the polymer obtained using the catalyst specified in the present invention is extremely narrow in its molecular weight distribution and small in the amount thereof extracted in hexane, and that the amount of low grade polymers by-produced is very small. Therefore, when film is formed using the polyolefin of a narrow molecular weight distribution prepared by the process of the present invention, it has a lot of merits, for example, high strength and transparency, superior anti-blocking property and heat-sealability.
The present invention will be described concretely hereinunder.
The catalyst used in the polyolefin preparing process of the present invention comprises a solid catalyst component and an organometallic compound, the said solid catalyst component being prepared from the following components [I], [II] and [III]:
[I] a reaction product obtained by the following components (1), (2) and (3) in the presence of a compound represented by the general formula R2OH wherein R2 is a hydrocarbon radical having 1 to 20 carbon atoms or an organic residue containing such an element as oxygen, nitrogen, sulfur, or chlorine:
(1) a silicon oxide and/or an aluminum oxide;
(2) a reaction product obtained by reacting a magnesium halide and a compound represented by the general formula [Me(OR)nXz-n] wherein Me represents an element of Groups I to IV in the Periodic Table, z represents the valence of the element Me, n is 0 less than nxe2x89xa6z, X is a halogen atom, and R is a hydrocarbon residue having 1 to 20 carbon atoms; and
(3) a titanium compound represented by the general formula Ti(OR1)mX4-m wherein R1 is a hydrocarbon radical having 1 to 20 carbon atoms, X is a halogen atom, and m is 0xe2x89xa6mxe2x89xa64;
[II] an organoaluminum compound represented by the general formula Al(OR3)pR4qX3-(p+q) wherein R3 and R4, which may be the same or different, are each a hydrocarbon residue having 1 to 24 carbon atoms, X is a halogen atom or hydrogen atom, and p and q are 0xe2x89xa6p less than 3, and 0xe2x89xa6qxe2x89xa63, provided 0 less than p+qxe2x89xa63; and
[III] a silicon compound represented by the general formula [R5aR6bR7cSi(OR8)dX4-(a+b+c+d)] where R5, R6, R7 and R8, which may be the same or different, are each a hydrocarbon residue having 1 to 20 carbon atoms, X is a halogen atom, and a, b, c and d are 0xe2x89xa6a less than 4, 0xe2x89xa6b less than 4, 0xe2x89xa6c less than 4 and 0 less than dxe2x89xa64, provided 0 less than a+b+c+dxe2x89xa64.
 less than 1 greater than Solid Catalyst Component
1. Component [I]
(1). The silicon oxide used in the present invention is silica or a double oxide of silicon and at least one another metal selected from Groups VII of the Periodic Table.
The aluminum oxide used as component (1) in the present invention is alumina or a double oxide of aluminum and at least one another metal selected from Group I to VIII in the Periodic Table.
As typical examples of the double oxide of silicon or aluminum and at least one another metal selected from Group VII in the Periodic Table there are mentioned various natural and synthetic double oxides such as Al2O3.MgO, Al2O3.CaO, Al2O3.SiO2, Al2O3.MgO.CaO, Al2O3.MgO.SiO2, Al2O3.CuO, Al2O3.Fe2O3, Al2O3.NiO, and SiO2.MgO. It is to be noted that these formulae are not molecular formulae but represent only compositions and that the structure and component ratio of the double oxide used in the present invention are not specially limited thereby. It goes without saying that the silicon oxide and/or aluminum oxide used in the present invention may have a small amount of water absorbed therein or may contain a small amount of impurities.
Although the properties of the silicon oxide and/or aluminum oxide used in the present invention are not specially limited so far as the objects of the present invention are not adversely affected thereby, a silica having a particle diameter of 1 to 200 xcexcm, an average pour volume of greater than 0.3 ml/g and a surface area of greater than 50 m2/g is preferred. Also, it is preferably calcined at 200-800xc2x0 C. prior to use.
(2). As the magnesium halide there is used a substantially anhydrous one. Examples are magnesium dihalides such as magnesium fluoride, magnesium chloride, magnesium bromide, and magnesium iodide, with magnesium chloride being particularly preferred.
These magnesium halides may have been treated with electron donors such as alcohols, esters, ketones, carboxylic acids, ethers, amines, and phosphines.
As examples of the compound of the general formula Me(OR)nXz-n used in the present invention wherein Me represents an element of Groups Ia to IVa in the Periodic Table, z represents the valence of the element Me, n is 0 less than nxe2x89xa6z, X is a halogen atom, and R is a hydrocarbon residue preferably radical, having 1 to 20, preferably 1 to 8, carbon atoms such as, for example, alkyl, aryl, or aralkyl, and Rs may be the same or different, there are mentioned compounds represented by NaOR, Mg(OR)2, Mg(OR)X, Ca(OR)2, Zn(OR)2, Cd(OR)2, B(OR)3, Al(OR)3, Al(OR)2X, Al(OR)X2, Si(OR)4, Si(OR)3X, Si(OR)2X2, Si(OR)X3, and Sn(OR)4. More concrete and preferred examples are Mg(OC2H5)2, Mg(OC2H5)Cl, Al(OCH3)3, Al(OC2H5)3, Al(On-C3H7)3, Al(Oi-C3H7)3, Al(On-C4H9)3, Al (Osec-C4H9)3, Al(Ot-C4H9)3, Al(OCH3)2Cl, Al(OC2H5)2Cl, Al(OC2H5)Cl2, Al(Oi-C3H7)2Cl, Al(Oi-C3H7)Cl2, Si(OC2H5)4, Si(OC2H5)3Cl, Si(OC2H5)2Cl2, Si(OC2H5)Cl3, Si(OCH2C6H5)4, B(OCH3)3, B(OC2H5)3, B(On-C4H9)3 and the like. It is preferable that the reaction ratio of the compound of the general formula Me(OR)nXz-n to the magnesium halide is in the range of 0.01 to 10, preferably 0.1 to 5 in terms of Me/Mg (molar ratio).
The method of reaction between the magnesium halide and the compound of the general formula Me(OR)nXz-n is not specially limited. There may be adopted a method in which both components are co-pulverized using, for example, ball mill, vibration mill, rod mill, or impact mill, at a temperature of 0xc2x0 to 200xc2x0 C., for 30 minutes to 50 hours, in the presence or absence of an inert hydrocarbon solvent. Or there may be adopted a method in which both components are mixed and reacted together under heating at a temperature of 20xc2x0 to 400xc2x0 C., preferably 50xc2x0 to 300xc2x0 C., for 5 minutes to 10 hours, in an organic solvent selected from inert hydrocarbons, alcohols, phenols, ethers, ketones, esters, nitriles and mixtures thereof, and thereafter the solvent is evaporated off. The method of co-pulverizing the two is preferred in the present invention.
(3). As examples of the titanium compound of the general formula Ti(OR1)mX4-m used in the present invention wherein R1 is a hydrocarbon radical having 1 to 20, preferably 1 to 12, carbon atoms such as an alkyl, aryl or aralkyl group, X is a halogen atom, and n is 0xe2x89xa6mxe2x89xa64, there are mentioned titanium tetrahalides such as titanium tetrachloride, titanium tetrabromide and titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxymonochlorotitanium, tetramethoxytitanium, monoethoxytrichlorotitanium, monoethoxytrifluorotitanium, monoethoxytribromotitanium, diethoxydifluorotitanium, diethoxydichlorotitanium, diethoxydibromotitanium, triethoxyfluorotitanium, triethoxychlorotitanium, tetraethoxytitanium, monopropoxytrichlorotitanium, monoisopropoxytrichlorotitanium, dipropoxydichlorotitanium, diisopropoxydichlorotitanium, diisopropoxydibromotitanium, tripropoxyfluorotitanium, tripropoxychlorotitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, monobutoxytrichlorotitanium, monoisobutoxytrichlorotitanium, dibutoxydichlorotitanium, diisopropoxydichlorotitanium, tributoxyfluorotitanium, tributoxychlorotitanium, triisobutoxychlorotitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetra-sec-butoxytitanium, tetra-tert-butoxytitanium, monopentyloxytrichlorotitanium, dipentyloxydichlorotitanium, tripentyloxymonochlorotitanium, tetra-n-pentyloxytitanium, tetra-cyclopentyloxytitanium, monooctyloxytrichlorotitanium, dioctyloxydichlorotitanium, trioctyloxymonochlorotitanium, tetra-n-hexyloxytitanium, tetra-cyclohexyloxytitanium, tetra-n-heptyloxytitanium, tetra-n-octyloxytitanium, mono-2-ethylhexyloxytrichlorotitanium, di-2-ethylhexyloxydichlorotitanium, tri-2-ethylhexyloxymonochlorotitanium, tetranonyloxytitanium, tetradecyloxytitanium, tetraisobornyloxytitanium, tetraoleyloxytitanium, tetraallyloxytitanium, tetrabenzyloxytitanium, tetrabenzhydryloxytitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium, triphenoxychlorotitanium, tri-o-xylenoxychlorotitanium, tetraphenoxytitanium, tetra-o-methylphenoxytitanium, tetra-m-methylphenoxytitanium, tetra-1-naphthyloxytitanium, tetra-2-naphthyloxytitanium and mixtures thereof. Among them, particularly, titanium tetrachloride, monoethoxytrichlorotitanium, diethoxydichlorotitanium, monobutoxytrichlorotitanium, dibutoxydichlorotitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetra-n-hexyloxytitanium, tetra-n-octyloxytitanium and tetra-2-ethylhexyloxytitanium are preferred.
(4) The component [I] used in the present invention is prepared by reacting together (1) a silicon oxide and/or an aluminum oxide (component [I]-(1)), (2) a reaction product obtained by the reaction of a magnesium halide and a compound of the general formula Me(OR)nXz-n (component [I]-(2)) and (3) a titanium compound of the general formula Ti(OR1)mX4-m (component [I]-(3)) in the presence of a compound of the general formula R2OH.
Compounds of the general formula R2OH are those wherein R2 is a hydrocarbon radical having 1 to 20, preferably 6 to 12, carbon atoms, or an organic residue containing such an element as oxygen, nitrogen, sulfur, or chlorine. Preferred examples of such hydrocarbon radical are alkyl, alkenyl, aryl and aralkyl. Particularly preferred are those having a branch structure. As examples of the compound of the general formula R2OH there are mentioned 1-hexanol, 2-methyl-1-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-pentanol, 3-heptanol, 4-heptanol, 2,4-dimethyl-3-pentanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 3,5-dimethyl-1-hexanol, 2,2,4-trimethyl-1-pentanol, 1-nonanol, 5-nonanol, 3,5-dimethyl-4-heptanol, 2,6-dimethyl-4-heptanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, 1-undecanol, 1-dodecanol, 2,6,8-trimethyl-4-nonanol, 1-tridecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, 1-eicosanol, phenol, chlorophenol, benzyl alcohol, methyl cellosolve, and mixtures thereof. Particularly, 2-methyl-1-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,4-dimethyl-3-pentanol, 2-ethyl-1-hexanol, 3,5-dimethyl-1-hexanol, 2,2,4-trimethyl-1-pentanol, 3,5-dimethyl-4-heptanol, 2,6-dimethyl-4-heptanol and 3,5,5-trimethyl-1-hexanol are preferred.
It goes without saying that methanol commercially available as industrial grade alcohol or other modified alcohols such as hexane-modified alcohols may also be used without any trouble.
How to react the components [I]-(l) to [I]-(3) in the preparation of component [I] is not specially limited if only the reaction is conducted in the presence of a compound of the general formula R2OH. These components may be reacted with one another in any of the following orders:
(A) Components [I]-(l) to [I]-(3) are contacted at a time.
(B) Components [I]-(1) and [I]-(2) are contacted together, followed by contact with component [I]-(3).
(C) Components [I]-(1) and [I]-(3) are contacted together, followed by contact with component [I]-(2).
(D) Components [I]-(2) and [I]-(3) are contacted together, followed by contact with component [I]-(1). The above method (D) is preferred. More preferably, components [I]-(2) and [I]-(3) are dissolved and contacted together in advance, using a compound of the general formula R2OH as a solvent, followed by contact with component [I]-(1). In what order the components [I]-(2) and [I]-(3) should be dissolved in the compound of the general formula R2OH is not specially limited. Both may be dissolved at a time, or one may precedes the other.
There also may be adopted the following method. Component [I]-(2) and/or component [I]-(3) are (is) dissolved beforehand in a compound smaller in the number of carbon atom than the compound of the general formula R2OH, namely a compound having 1 to 5 carbon atoms, which is a so-called lower alcohol, and thereafter the components to be reacted are contacted together using the lower alcohol solution containing the component [I]-(2) and/or the component [I]-(3) and in the presence of the compound of the general formula R2OH.
According to a preferred method of contacting the components [I]-(1) to [I]-(3), these components are contacted, mixed and reacted in accordance with any of the foregoing contacting orders at a temperature of 20-300xc2x0 C., preferably 50-150xc2x0 C., for 1 minute to 48 hours, preferably 1 to 5 hours, in the presence of a compound of the general formula R2OH, and thereafter the compound of the general formula R2OH is removed by the reduction of pressure and/or heating.
As to the reaction ratio of the components, it is desirable to react the components [I]-(1) and [I]-(2) in such a manner that the magnesium content in the component [I]-(2) becomes 0.01 to 20 mmol, preferably 0.1 to 10 mmol, more preferably 0.2 to 4.0 mmol, per gram of the component [I]-(1). As to the components [I]-(1) and [I]-(3), it is preferable that the reaction be carried out using 0.01-10.0 mmol, preferably 0.1-5.0 mmol, more preferably 0.2-2.0 mmol, of component [I]-(3) per gram of component [I]-(1), although this ratio differs depending on whether the component [I]-(1) is subjected to a calcining treatment or not or conditions for the calcining treatment if applied.
As to the amount of the compound of the general formula R2OH to be used, it is desirable to use this compound in an amount of 0.1 to 50 g, preferably 1 to 30 g, per gram of component [I]-(2).
2. Component [II]
As examples of the organoaluminum compound of the general formula Al(OR3)pR4qX3-(p+q) used in the present invention wherein R3 and R4, which may be the same or different, are each a hydrocarbon residue preferably radical, having 1 to 24, preferably 1 to 12, carbon atoms, X is a halogen atom or hydrogen atom, and p and q are 0xe2x89xa6p less than 3 and 0xe2x89xa6qxe2x89xa63, provided 0 less than p+qxe2x89xa63 are dimethylaluminum methoxide, dimethylaluminum ethoxide, dimethylaluminum isopropoxide, dimethylaluminum t-butoxide, dimethylaluminum n-butoxide, dimethylaluminum sec-butoxide, diethylaluminum methoxide, diethylaluminum ethoxide, diethylaluminum isopropoxide, diethylaluminum n-butoxide, diethylaluminum sec-butoxide, diethylaluminum cyclohexyloxide, diethylaluminum t-butoxide, dipropylaluminum ethoxide, dipropylaluminum t-butoxide, dibutylaluminum t-butoxide, di-i-butylaluminum methoxide, di-i-butylaluminum ethoxide, di-i-butylaluminum isopropoxide, di-i-butylaluminum i-butoxide, di-i-butylaluminum t-butoxide, di-t-butylaluminum ethoxide, di-t-butylaluminum t-butoxide, dimethylaluminum phenoxide, di-n-hexylaluminum ethoxide, di-n-hexylaluminum isopropoxide, ethylethoxyaluminum chloride, isobutylethoxyaluminum chloride, ethylphenoxyaluminum chloride, phenylethoxyaluminum chloride, ethylethoxyaluminum hydride, ethylmethoxyaluminum chloride, ethylisopropoxyaluminum chloride, ethylbutoxyaluminum chloride, phenylaluminum dichloride, diphenylaluminum chloride, benzylaluminum dichloride, dibenzylaluminum chloride, dimethylaluminum chloride, diethylaluminum fluoride, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, di-isobutylaluminum chloride, methylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquibromide, methylaluminum dichloride, ethylaluminum dichloride, isobutylaluminum dichloride, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-isobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum and mixtures. Particularly, diethylaluminum chloride, ethylaluminum sesquichloride and ethylaluminum dichloride are preferred.
3. Component [III]
As the compound represented by the general formula [R5aR6bR7cSi(OR8)dX4-(a+b+c+d)] there may be used those wherein R5, R6, R7 and R8, which may be the same or different, are each a hydrocarbon radical having 1 to 20 carbon atoms, preferably 1-12 carbon atoms, such as hydrocarbon radical such as alkyl, aryl or aralkyl, X is hydrogen atom or a halogen atom such as chloro, bromo or iodo, and a, b, c and d are 0xe2x89xa6a less than 4, 0xe2x89xa6b less than 4, 0xe2x89xa6c less than 4 and 0 less than dxe2x89xa64, provided 0 less than a+b+c+dxe2x89xa64.
Examples of the silicon compound include various compounds represented by Si(OR8)4, Si(OR8)3X, Si(OR8)2X2, Si(OR8)X3, R5Si(OR8)3, R5Si(OR8)2X, R5Si(OR8)X2, R5R6Si(OR8)2, R5R6Si(OR8)X, R5R6R7Si(OR8) and the like. Concrete examples are Si(OCH3)4, Si(OC2H5)4, Si(Oi-C3H7)4, Si(On-C4H9)4, Si(OCH3)3Cl, Si(OC2H5)3Cl, Si(Oi-C3H7)3Cl, Si(On-C4H9)3Cl, Si(Osec-C4H9)3Cl, Si(OCH3)2Cl2, Si(OC2H5)2Cl2, Si(Oi-C3H7)2Cl2, Si(On-C4H9)2Cl2, Si(OC8H17)2Cl2, Si(OCH3)Cl3, Si(OC2H5)Cl3, Si(Oi-C3H7)Cl3, Si(On-C4H9)Cl3, Si(OC5H11)Cl3, Si(OC8H17)Cl3, Si(OC18H37)Cl3, Si(OC6H5)Cl3, Si(Op-CH3C6H5)Cl3, CH3Si(OCH3)3, CH3Si(OC2H5)3, CH3Si(Oi-C3H7)3, C2H5Si(OCH3)3, C2H5Si(OC2H5)3, C2H5Si(Oi-C3H7)3, i-C3H7Si(OCH3)3, i-C3H7Si(OC2H5)3, i-C3H7Si(Oi-C3H7)3, n-C3H7Si(OCH3)3, n-C3H7Si(OC2H5)3, n-C3H7Si(Oi-C3H7)3, n-C4H9Si(OCH3)3, n-C4H9Si(OC2H5)3, i-C4H9Si(OCH3)3, i-C4H9Si(OC2H5)3, t-C4H9Si(OCH3)3, t-C4H9Si(OC2H5)3,
CH3Si(OCH3)2Cl, CH3Si(OC2H5)2Cl, CH3Si(Oi-C3H7)2Cl, CH3Si(OCH3)2Br, CH3Si(OC2H5)Br, CH3Si(Oi-C3H7)2Br, CH3Si(OCH3)2I, CH3Si(OC2H5)2I, CH3Si(Oi-C3H7)2I, C2H5Si(OCH3)2Cl, C2H5Si(OC2H5)2Cl, C2H5Si(Oi-C3H7)2Cl, C2H5Si(OCH3)2Br, C2H5Si(OC2H5)2Br, C2H5Si(Oi-C3H7)2Br, C2H5Si(OCH3)2I, C2H5Si(OC2H5)2l I, C2H5Si(Oi-C3H7)2I, i-C3H7Si(OCH3)2Cl, i-C3H7Si(OC2H5)2Cl, i-C3H7Si(Oi-C3H7)2Cl, n-C3H7Si(OCH3)2Cl, n-C3H7Si(OC2H5)2Cl, n-C3H7Si(Oi-C3H7)2Cl, n-C4H9Si(OCH3)2Cl, n-C4H9Si(OC2H5)2Cl, n-C4H9Si(Oi-C3H7)2Cl, i-C4H9Si(OCH3)2Cl, i-C4H9Si(OC2H5)2Cl, i-C4H9Si(Oi-C3H7)2Cl, t-C4H9Si(OCH3)2Cl, t-C4H9Si(OC2H5)2Cl, t-C4H9Si(Oi-C3H7)2Cl,
CH3Si(OCH3)Cl2, CH3Si(OC2H5)Cl2, CH3Si(Oi-C3H7)Cl2, C2H5Si(OCH3)Cl2, C2H5Si(C2H5)Cl2, C2H5Si(Oi-C3H7)Cl2, i-C3H7Si(OCH3)Cl2, i-C3H7Si(OC2H5)Cl2, n-C3H7Si(OCH3)Cl2, n-C3H7Si(OC2H5)Cl2, n-C4H9Si(OCH3)Cl2, n-C4H9Si(OC2H5)Cl2, i-C4H9Si(OCH3)Cl2, i-C4H9Si(OC2H5)Cl2, t-C4H9Si(OCH3)Cl2, t-C4H9Si(OC2H5)Cl2,
(CH3)2Si(OCH3)2, (CH3)2Si(OC2H5)2, (C2H5)2Si(OCH3)2, (C2H5)2Si(OC2H5)2, (i-C3H7)2Si(OCH3)2, (i-C3H7)2Si(OC2H5)2, (n-C3H7)2Si(OCH3)2, (n-C3H7)2Si(OC2H5)2, (n-C4H7)2Si(OCH3)2, (n-C4H9)2Si(OC2H5)2, (i-C4H9)2Si(OCH3)2, (i-C4H9)2Si(OC2H5)2, (t-C4H9)2Si(OCH3)2, (t-C4H9)2Si(OC2H5)2,
(CH3)(C2H5)Si(OCH3)2, (CH3)(C2H5)Si(OC2H5)2, (CH3)(i-C3 7)Si(OCH3)2, (CH3)(i-C3H7)Si(OC2H5)2, (CH3)(t-C4H9)Si(OCH3)2, (CH3)(t-C4H9)Si(OC2H5)2,
(C2H5)(i-C3H7)Si(OCH3)2, (C2H5)(i-C3H7)Si(OC2H5)2, (C2H5)(t-C4H9)Si(OCH3)2, (C2H5)(t-C4H9)Si(OC2H5)2,
(CH3)2Si(Oi-C3H7)2, (C2H5)2Si(Oi-C3H7)2, (i-C3H7)2Si(Oi-C3H7)2, (t-C4H9)2Si(Oi-C3H7)2,
(CH3)2Si(OCH3)Cl, (CH3)2Si(OC2H5)Cl, (C2H5)2Si(OCH3)Cl, (C2H5)2Si(OC2H5)Cl, (i-C3H7)2Si(OCH3)Cl, (i-C3H7)2Si(OC2H5)Cl, (t-C4H9)2Si(OCH3)Cl, (t-C4H9)2Si(OC2H5)Cl,
(CH3) (t-C4H9)Si(OCH3)Cl, (CH3)(t-C4H9)Si(OC2H5)Cl,
(CH3)2Si(Oi-C3H7)Cl, (C2H5)2Si(Oi-C3H7)Cl,
(CH3)(t-C4H9)Si(Oi-C3H7)Cl,
(CH3)3Si(OCH3), (CH3)3Si(OC2H5), (C2H5)3Si(OCH3), (C2H5)3Si(OC2H5), (CH3)2(t-C4H9)Si(OCH3), (CH3)2(t-C4H9)Si(OC2H5),
and the like. Among them, Si(OCH3)4, Si(OC2H5)4, Si(OCH3)3Cl, Si(OC2H5)3Cl, Si(OCH3)2Cl2, Si(OC2H5)2Cl2, (CH2)Si (OCH3)2Cl, (C2H5)Si(OC2H5)2Cl, (CH3)2Si(OCH3)2, (C2H5)2Si(OC5H5)2,
are most preferred.
4. Preparation of Solid Catalyst Component
The solid catalyst component used in the present invention is obtained by reacting the components [I] to [III] in any of the following orders:
(A) The components [I] and [II] are reacted at first, and then the component [III] is reacted with the above product.
(B) The components [I] and [III] are reacted at first, and then the component [II] is reacted with the above product.
(C) The components [II] and [III] are reacted at first, and then the component [I] is reacted with the above product.
(D) The components [I] to [III] are reacted at a time.
Reaction methods are not specially limited. For example, according to a preferred method, components to be reacted are contacted at a temperature of 0xc2x0 to 300+ C., preferably 20xc2x0 to 150xc2x0 C., for 5 minutes to 10 hours, in the presence or absence of an inert hydrocarbon solvent inert to conventional Ziegler catalysts, such as, for example, pentane, hexane, cyclohexane, heptane, octane, nonane, decane, benzene, toluene, or xylene. When the reaction is conducted in an inert hydrocarbon solvent, the solvent is preferably removed followed by the second stage reaction which may be conducted in the absence of any solvent or in the presence of a newly added solvent. Also, it is possible that the inert solvent is not removed after the first stage reaction, followed by the second stage reaction in the remaining solvent. Also, it is possible that the first stage reaction is conducted in the absence by evaporation or the like after the reaction. Of course, when the components [I], [II] and [III] are reacted stepwise in the manner as the above (A), (B) and (C), the first and/or second stage reaction may be conducted in the presence or absence of an inert hydrocarbon solvent. For example, the first stage reaction is conducted in an inert hydrocarbon solvent, and then the solvent is removed, of an inert solvent, followed by the second stage reaction in the absence of any solvent or in the presence of a newly added solvent.
As to the reaction ratio of the components [I], [II] and [III], the component [II] is preferably used in such a manner that the component [II]/{the component [I]-(3) in the component [I]} (molar ratio) is 0.01 to 100, more preferably 0.2 to 10, most preferably 0.5 to 5.0. The component [III] is preferably used in such a manner that the component [III]/{the component [I]-(3) in the component [I]} (molar ratio) is 0.01 to 10, more preferably 0.03 to 5.0, most preferably 0.05 to 1.0.
Of course, the reactions for the preparation of each component and the solid catalyst component should be performed in an inert gas atmosphere, and moisture should be avoided.
 less than 2 greater than  Organometallic Compound
The catalyst used in the present invention comprises the above mentioned solid catalyst component and an organometallic compound.
As the organometallic compound used in the present invention, there may be preferably employed an organometallic compound of a metal of Groups I-IV in the Periodic Table which is known as a component of Ziegler type catalyst. Particularly preferred are organoaluminum compounds and organozinc compounds. To illustrate these compounds, mention may be made of organoaluminum compounds of the general formulae R3Al, R2AlX, RAlX2, R2AlOR, RAl(OR)X and R3Al2X3 wherein R, which may be the same or different, is an alkyl or aryl group having 1 to 20 carbon atoms and X is a halogen atom, as well as organozinc compounds of the general formula R2Zn wherein R, which may be the same or different, is an alkyl group having 1 to 20 carbon atoms. Concrete examples are trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisopropylaluminum chloride, diethylaluminum ethoxide, ethylaluminum sesquichloride, diethylzinc, and mixtures thereof.
The amount of the organometallic compound used is not specially limited. But usually it is in the range of 0.1 to 1,000 moles per mole of the titanium compound.
It is also preferable in the present invention that the organometallic compound component be used as a mixture or addition compound of the organometallic compound and an organic acid ester.
Where the organometallic compound component is used as a mixture of the organometallic compound and an organic acid ester, the organic acid ester is used usually in an amount of 0.1 to 1 mole, preferably 0.2 to 0.5 mole, per mole of the organometallic compound. Where it is used as an addition compound of the organometallic compound and the organic acid ester, the molar ratio is preferably in the range of 2:1 to 1:2.
The organic acid ester is the ester of a saturated or unsaturated, mono- or dibasic organic carboxylic acid having 1 to 24 carbon atoms and an alcohol having 1 to 30 carbon atoms. Examples are methyl formate, ethyl acetate, amyl acetate, phenyl acetate, octyl acetate, methyl methacrylate, ethyl stearate, methyl benzoate, ethyl benzoate, n-propyl benzoate, iso-propyl benzoate, butyl benzoate, hexyl benzoate, cyclopentyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzoic acid-4-tolyl, methyl salicylate, ethyl salicylate, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, phenyl salicylate, cyclohexyl p-hydroxybenzoate, benzyl salicylate, ethyl xcex1-resorcinol carboxylate methyl anisate, methyl p-ethoxybenzoate, methyl p-toluylate, ethyl p-toluylate, phenyl p-toluylate, ethyl o-toluylate, ethyl m-toluylate, methyl p-aminobenzoate, ethyl p-aminobenzoate, vinyl benzoate, allyl benzoate, benzyl benzoate, methyl naphthoate, and ethyl naphthoate.
Particularly preferred are alkyl esters, especially methyl esters, of benzoic acid, o- or p-toluic acid and anisic acid.
 less than 3 greater than  Polymerization of Olefin
The olefin polymerization using the catalyst of the present invention can be performed in the form of slurry polymerization, solution polymerization or vapor phase polymerization. The catalyst used in the present invention is particularly suitable for vapor phase polymerization. The polymerization reaction is carried out in the same way as in the conventional olefin polymerization reaction using a Ziegler type catalyst. More particularly, the reaction is performed in a substantially oxygen- and water-free condition in the presence or absence of an inert hydrocarbon. Olefin polymerizing conditions involve temperatures in the range of 20xc2x0 to 120xc2x0 C., preferably 50xc2x0 to 100xc2x0 C., and pressures in the range of atmospheric pressure to 70 kg/cm2, preferably 2 to 60 kg/cm2. Adjustment of the molecular weight can be done to some extent by changing polymerization conditions such as the polymerization temperature and the catalyst mole ratio, but the addition of hydrogen into the polymerization system is more effective for this purpose. Of course, using the catalyst of the present invention, there can be performed two or more multi-stage polymerization reactions involving different polymerization conditions such as different hydrogen concentrations and different polymerization temperatures.
The process of the present invention is applicable to the polymerization of all olefins that can be polymerized using a Ziegler type catalyst, preferably xcex1-olefins having 2 to 12 carbon atoms. For example, it is suitable for the homopolymerization of such xcex1-olefins as ethylene, propylene, 1-butene, 1-hexene and 4-methyl-1-pentene and the copolymerization of ethylene and an xcex1-olefin having 3-12 carbon atoms such as propylene, 1-butene, 1-hexene and 4-methylpentene-1, the copolymerization of propylene and 1-butene and the copolymerization of ethylene and one or more xcex1-olefins.
Copolymerization with dienes is also preferable for the modification of polyolefins. Examples of diene compounds which may be used for this purpose are butadiene, 1,4-hexadiene, ethylidene norbornene and dicyclopentadiene. The comonomer content in the copolymerization may be selected optionally. For instance, when ethylene and a xcex1-olefin having 3-12 carbon atoms is copolymerized, the xcex1-olefin content in the copolymer is preferably 0-40 molar %, more preferably 0-30 molar %.
 less than Effects of the Invention greater than
Homopolymers or copolymers of olefins prepared by using as catalyst the solid catalyst component and the organometallic compound in the present invention are remarkably high in bulk density, relatively large in average particle diameter and narrow in particle size distribution and have a reduced proportion of fine particles, so there is little adhesion of polymer to the reactor walls during polymerization thus permitting stable operations. Besides, not only dusting can be prevented in a forming operation and so the efficiency of the forming operation can be enhanced, but also it is possible to omit a pelletizing step.
Further, since the homopolymers or copolymers in question according to the present invention are narrow in molecular weight distribution, they can be formed into films having high strength and superior in transparency and also superior in anti-blocking property and heat-sealability.


A method for imparting an aluminide coating to an alloy gas turbine engine component, heat treating the component, and quenching the component. The component is exposed to a source of aluminum at an elevated temperature in a coating furnace to deposit an aluminum-based oxidation barrier on the component, heated in the coating furnace to a temperature of at least the solution temperature of the alloy, and quenched by flowing a chilled inert gas around the component in the coating furnace to cool the component from the temperature of at least the solution temperature of the alloy to a temperature at which a gammaxe2x80x2 phase of the alloy is set in the alloy in less than about 10 minutes.

This invention relates to a method for coating components of gas turbine engines, such as by aluminide coating, heat treating the components, and rapidly quenching the components in a combined operation using a single apparatus.
To provide protection against high temperature oxidation and hot corrosion, components of gas turbine engines such as turbine airfoils are subjected to, for example, diffusion aluminide coating. Diffusion coatings are imparted by a thermal/chemical reaction process typically requiring a reducing or inert atmosphere at an elevated temperature. A diffusion aluminide coating, for example, may be imparted at roughly 1975xc2x0 F. (1080xc2x0 C.).
Engine components are often strengthened after diffusion coating by being subjected to aging. In order to optimize these aging effects, it is necessary to first set the gxe2x80x2 (gamma prime) phase by quenching the components rapidly to below the age temperature after holding the component steady for, for example, 4 hours, at the alloy solution temperature. Heretofore, it has only been possible to achieve the quench rate necessary to set the gxe2x80x2 phase by using a vacuum furnace. Such furnaces have not been employed for coating operations because the byproducts from such operations damage the furnace""s ability to maintain desired vacuum level. Furnaces suitable for coating operations have not been able to achieve the rapid quench rate required to set the gxe2x80x2 phase. Diffusion coating furnaces have not been capable of quenching the components to below the age temperature sufficiently rapidly. As such, aluminide coated components have been coated in a diffusion coating furnace, allowed to cool, removed from the diffusion coating furnace, placed in a heat treatment furnace, heated to the solution temperature, held at that temperature for the required time period, then rapidly quenched.
Briefly, therefore, the invention is directed to a method for imparting an aluminide coating to an alloy gas turbine engine component, heat treating the component, and quenching the component by exposing the component to a source of aluminum at an elevated temperature in a coating furnace to deposit an aluminum-based oxidation barrier on the component, heating the component in the coating furnace to a temperature of at least the solution temperature of the alloy, and quenching the component by flowing an inert gas around the component in the coating furnace to cool the component from the temperature of at least the solution temperature of the alloy to a temperature at which a gammaxe2x80x2 phase of the alloy is set in the alloy in less than about 10 minutes.
In another aspect, the invention is directed to a method for imparting an aluminide coating to alloy gas turbine engine components, heat treating the components, and quenching the components, all in a coating vessel of a coating furnace such that the ratio of the mass of the components to the volume of the coating vessel is less than about 12 lbs/cubic foot (200 kg/cubic meter).
The invention is further directed to a method for imparting an aluminide coating to a plurality of Ni-based alloy gas turbine engine components, heat treating the components, and quenching the components in which the components are arranged irregularly with respect to each other in a coating can in a coating furnace to reduce reflection of heat between said components, thereby facilitating rapid quenching.

Combined coat, heat treat, quench method for gas turbine engine components


Systems and methods have been developed for promoting media objects to users. More specifically, systems and methods have been developed for profiling a user media repository and delivering promotional media objects to the user's media repository based upon the profile.

Increasingly the Internet and other networks (e.g., wired and wireless networks) are utilized to transmit content in the form of media objects (e.g., video, audio, etc.) between users and content providers or distributors. Users may consume (e.g., watch, listen to, etc.) or otherwise utilize this content in various locations and with various media applications (e.g., client devices). Advertisers, promoters and other third parties who wish to market or otherwise offer media objects to users often must evaluate market trends in order to determine what kind of content will appeal to consumers.


Methods for remotely detecting a gun muzzle flash, using frequency-optimized detection methods. Small explosive charges are best detected at I/R and visible wavelengths, using optical detectors, whereas large explosive charges may also be detected with antennas. Details of the time course and spectral properties of the flash can be used to distinguish gun muzzle flashes from other radiation.

The remote detection of a gun that has just launched a projectile is of interest in both military and civil situations. Immediate and accurate location of a firing gun enables retaliatory action to remove the threat. It also makes feasible the deployment of protective systems. This is of great interest both in large conventional battlefield maneuvers and in the growing number of isolated sniper and ambush-type situations.
A literature survey of discussions of electromagnetic radiation from detonation of conventional explosives is contained in a report by Jonathon E. Fine and Stephen J. Vinci, "Causes of Electromagnetic Radiation from Detonation of Conventional Explosives: A Literature Survey", Army Research Lab Adelphi, (December, 1998), also available at www.stormingmedia.us/cgi-bin/04/0479/A047953-83-1t.php. This report states that observers have detected radiation at frequencies as low as 0.5 Hz and up to as high as 2 GHz. Many investigators believe that the likeliest cause is charged particles created by ionization within the explosive region.
Although some modeling and observations have been reported, analysis has been crude and observations have been few. Detailed dependences of the radiation on the size of the explosive charge or with observation wavelength have not been determined. As a result, it is not clear what the optimum wavelengths are to use for observing the gun fire, or how distant the detection apparatus might be from the gun.

Frequency-optimized detection of gun muzzle flashes


A filter apparatus for filtering fluids such as gases or liquids includes a casing defining an inlet and an outlet, and having a peripheral wall extending between the inlet and outlet. The peripheral wall defines a chamber having a longitudinal axis and a cross-sectional area, when viewed in the direction of the longitudinal axis, which increases between the inlet and the outlet. A bed of particulate filtering media is disposed within the chamber, the media ranging in size between relatively large particles disposed adjacent the inlet and smaller particles disposed closer to the outlet. Preferably, the size of the particles is chosen based upon the relationship between the lifting force exerted on the particles by a fluid flowing upward through the chamber and the weight of the particles. As the lifting force exerted on the particles varies, due to varying velocity of the fluid passing upward through the chamber, the size of the particles is also varied at a corresponding rate so that all particles are effected equally by the lifting force of the fluid and mixing of the particles is inhibited.

1. Field of the Invention
The present invention relates generally to devices for filtration of fluids, and in particular to an apparatus for filtering fluids through the use of a casing defining a chamber of variable cross-sectional area along the length thereof for receiving a bed of stratified particulate filtering media.
2. Discussion of the Prior Art
It is well known to filter water and other fluids by passing it through a bed of porous medium, such as sand, anthracite or a combination of both. Filtration is used to produce water of suitable quality for drinking and most industrial uses, including process fluid filtration, waste water treatment, water re-use, gas cleaning, boiler makeup or special processing cooling purposes.
The purpose of filtration is to remove particulate matter from the fluid. More sophisticated filtration systems are needed where it is desired to remove the highest percentage of particulate matter. Filtration involves adsorption, straining, sedimentation, interception, diffusion and inertial compaction.
Conventional filters may be of either gravity or pressure construction. In most such filters, the flow of fluid is downward. Sand or anthracite is usually the filter medium in a bed consisting of either one or two grades of sand or anthracite, with a total depth of 15 to 30 inches. Further, a gravel bed supports the filter medium, and prevents fine sand or anthracite from passing into the underdrain system and distributes backwash water. The supporting bed consists of 1/8 to 11/2 inch gravel in graded layers to a depth of 12 to 16 inches.
One variant of the conventional filter is a stratified upflow filter. In stratified upflow filters, a single medium of graded sand is often used, with the finest sand grade at the top of the bed, and the coarsest sand below. Gravel is generally located at the bottom of the unit retained in a fixed position by grids. The gravel is used to ensure proper water distribution during the service cycle. During operation, larger, coarse particles are removed at the bottom of the bed, while smaller particles are allowed to penetrate further into the media. Typical service flow rates are 5 to 10 gpm/sq.ft.
Conventional fluid filters of the type described above perform adequately in most environments, but experience common problems. One of the principal problems which must be addressed by all filters of this type is that, while the obvious purpose of the filter is to trap as much particulate matter as possible through the initial contact of the water with the filtration media, at the same time some penetration of the media is absolutely essential to prevent rapid loss of pressure head. In other words, in order to promote efficiency, it is beneficial to strike the most positive balance between the highest rate of flow and the lowest loss of pressure head on the one hand, and the highest degree of effluent quality on the other. Conventional filters frequently have difficulty in achieving a high degree of efficiency.
A second problem, related to the first, is created by the need to backwash the filter system in order to remove trapped particulate matter. Because of the relative inefficiency of many conventional filtration systems, it is necessary to backwash such systems at short intervals in order to remove the particles and restore the filter to its maximum efficiency. This frequent backwashing further reduces efficiency by removing the filtration system from its filtering cycle.
Yet another difficulty is presented by the backwashing itself. That is, each backwashing cycle causes fluidization of the particulate media, causing the smaller media to migrate within the chamber and mix with the larger media. This migration is aggravated by the need for frequent backwashing in less efficient conventional filters. The net result of the mixing is frequently to upset the stratification of the bed, thus further decreasing the efficiency of the filter.

Kansas State University Research Foundation


A DRAM comprising word lines parallel to an X-axis and bit lines parallel to a Y-axis wherein the memory cell consists of a transistor and a stacked-type charge-storage capacitor is disclosed. The storage node electrode of the stacked-type charge-storage capacitor is formed to project on the surface of the silicon substrate a rectangle of which the major sides are oblique to the X-axis and Y-axis or a pattern consisting of at least two different rectangles. Thereby the perimeter of the storage node electrode becomes more than that in the prior art. This enables the realization of charge-storage capacitors having larger capacitance value than in a conventional DRAM under the same manufacturing conditions. This effect is marked under the conditions where the film thickness of the storage node electrode is more than 1/2 of the minimum feature size, and the distance between two adjacent storage node electrodes is equal to the minimum feature size.

1. Field of the Invention
This invention relates to a semiconductor memory device, and more particularly to the shape and arrangement of storage node electrodes of the charge-storage capacitors in a DRAM comprising memory cells each consisting of a transistor and a stacked-type charge-storage capacitor.
2. Description of the Prior Art
DRAM stores information as an electric charge in charge-storage capacitors. From the viewpoint of stable operation and the memory retention time, it is desired to make the capacitance of the charge-storage capacitor as large as possible. On the other hand, it is needed for higher integration of DRAM to miniaturize the memory cell, accompanied by to smaller allowable projective plane area for the charge-storage capacitor. The projective plane area is smaller than the size of the memory cell. For solving this contradiction, in the DRAM comprising memory cells each consisting a transistor and a charge-storage capacitor, as the structure of the charge-storage capacitor became used firstly planar type, followed by trench type, and then stacked type. With deeper trench, the trench-type charge-storage capacitor can have larger side-face area accompanied by increasing capacitance. The stacked-type charge-storage capacitor can have larger capacitance due to the storage node electrode essentially higher or thicker, and hence having larger side face area. The newest stacked-type charge-storage capacitor is intended to have further increased capacitance by the use of fin-structured storage node electrode. (Fin-structure has been impossible to be applied to trench type.) Unless specified structure such as fin-structure is taken into consideration, the capacitance of the charge-storage capacitor depends only on the surfaces of the top and side faces of the storage node electrode.
Of recent stacked-type DRAMs, the most compact one is exemplified in IDEM Technical Digest pp. 596-599, 1988.
On the surface of a p-type substrate, word lines parallel to the X-axis and bit lines parallel to the Y-axis orthogonal with the X-axis are formed as a matrix arrangement. The size of the memory cell in the DRAM is 2Pw.times.P.sub.B, Pw being the pitch of the word lines (the word line width plus the distance between the word lines) and P.sub.B being the pitch of the bit lines (the bit line width plus the distance between the bit lines). An active area is formed of, for example, an area defined by the ith and i+1th bit lines and the jth and j+1th word lines, for example, an area defined by the i+1th and i+2th bit lines and the j+2th and j+3th word lines, and an area connecting between these areas. This active area includes a n.sup.+ -type self-aligned diffusion regions. The n.sup.+ -type diffusion region defined by the ith and i+1th bit lines and the jth and j+1th word lines serves as node diffusion region for (i+1, J+1) bit. The n.sup.+ -type diffusion region between j+1th and j+2 word lines serves as bit diffusion region for (i+1, J+1) bit and (i+1, j+2) bit. The n.sup.+ -type diffusion region defined by i+1th and i+2the bit lines and j+2th and j+3th word lines serves as node diffusion region for (i+1, j+2) bit. The j+1th word line, the node diffusion region for (i+1, J+1) bit, and the bit diffusion region for (i+1, J+1) bit and (i+1, J+1) bit constitute a transistor for (i+1, j+1) bit. Similarly the j+2th word line, the node diffusion region for (i+1, J+2) bit, and the bit diffusion region for (i+1, J+1) bit and (i+1, J+2) bit constitute a transistor for (i+1, j+2) bit.
The bit diffusion region for (i+1, J+1) bit and (i+1, J+2) bit is provided with a bit contact hole connecting to i+1th bit line. The node diffusion region for (i+1, j+1) bit is provided with a storage node contact hole connecting to the storage node electrode for a charge-storage capacitor of (i+1, j+1) bit. The node diffusion region for (i+1, j+2) bit is provided with a storage node contact hole connecting to the storage node electrode for a charge-storage capacitor of (i+1, j+2) bit. The top faces of the storage node electrodes of these charge storage capacitors project generally rectangles on the surface of the silicon substrate. Of the rectangle, the major sides are parallel to bit lines or Y-axis and the minor sides to word lines or X-axis.
In such a stacked-type DRAM, the capacitance of a charge-storage capacitor is created by a storage node electrode, a cell plate electrode and a capacitive dielectric film between these electrodes. The capacitance value of the charge-storage capacitor depends on the dielectric constant and the thickness of the capacitive insulating film, and the electrode area which is the area of the opposed surfaces of the storage node electrode and the cell plate electrode. Assuming capacitive insulating film is of a certain kind and has a fixed thickness, then only increase of the electrode area is responsible for increase in the capacitance value of this capacitor. The electrode area is equal to the surface area of the storage node electrode.
Of the storage node electrode, the surface area A.sub.T0 is the sum of the area A.sub.t0 of the top face and the area A.sub.s0 of the side face. Strictly speaking, the top face is a curved surface which projects an area smaller than the cell size 2Pw.times.P.sub.B on the surface of the silicon substrate. Using minimum feature size for fabricating this DRAM, F, as the distance between two storage node electrodes gives the maximum value of A.sub.T0. Under this condition, the top face projects a rectangle of which the major sides are parallel to bit lines on the silicon substrate surface. The rectangle has an area of (2Pw-F).times.(P.sub.B -F) and a perimeter, L.sub.P0, of 2.times.(2Pw+P.sub.B -2F). Assuming d in the film thickness or height of the storage node electrode, the area of the size face, A.sub.s0, is given as 2.times.(2Pw+P.sub.B -2F).times.d.
The conventional method for increasing the surface area of the storage node electrode, A.sub.T0, is generally to reduce F, especially to increase d. Further increase of it can be achieved by forming irregularities on the top and side faces. Such methods for increasing the storage node electrode surface area, A.sub.T0, however, involve process of fabrication, and thus the increase of A.sub.T0 is limited by the manufacture techniques of the times so far as the shape and arrangement of storage node electrodes in the prior art are used. In other wores, it is impossible to increase the perimeter and also the surface area A.sub.T0 of the storage node electrode independent of manufacture techniques.

Semiconductor memory device having stacked-type capacitor of large capacitance


A dimming control circuit for dimming light emitting diodes receives an AC input voltage signal from a dimming circuit. The control circuit includes a power stage and a current control loop coupled to the power stage. An AC detector is operable to detect an instantaneous value of the AC input voltage signal and to generate a signal indicating whether the AC input voltage signal is present or absent. A current control circuit is operable responsive to the signal to adjust the operation of the current control loop and to control current through the light emitting diodes to achieve the desired dimming, and to prevent inrush current on the AC input voltage signal.

Conventional incandescent lighting systems utilize dimming control circuits or dimmers to adjust the intensity or brightness of light provided by the system. A conventional dimmer works by adjusting the portion of an alternating current (AC) half wave that is supplied to the incandescent light being powered. Such an AC signal is a sinusoidal AC power signal and the "half wave" of the signal corresponds to this sinusoidal signal during half the period of the signal, as will be understood by those skilled in the art. The portion of the AC power signal that is actually supplied through the dimmer to an incandescent light or other load being powered is commonly referred to as the "conduction angle" of the AC power signal. To control the brightness of the light provided by the system the dimmer reduces the portion of each AC half wave that is supplied to the light and thereby controls the root-mean-square (RMS) voltage supplied to the light. The RMS voltage supplied to the light determines the brightness of the light being provided and in this way the dimmer controls the brightness.
In light emitting diode (LED) lighting systems, which are becoming popular replacements for conventional incandescent lighting systems, control circuitry operates to maintain a desired average current supplied to the LEDs being powered to thereby achieve the desired illumination. These control systems maintain the desired average current independent of variation in the supplied AC input voltage. As a result, conventional dimmers cannot be utilized with these LED control circuits since the control circuits will simply adjust the current supplied to the LEDs to maintain the desired average current in response to changes in the AC input voltage caused by the dimmer. It is, however, desirable to utilize conventional dimmers with such LED lighting systems to provide compatibility of LEDs with existing incandescent lighting systems.

Method and system for dimming AC-powered light emitting diode (LED) lighting systems using conventional incandescent dimmers


The present invention is a device, which illuminates light inside of a tractor trailer truck van and other loading vehicles at a loading dock during loading and unloading procedures. As professionals working with such vehicles understand, natural lighting is simply not enough to prevent serious loading and unloading accidents, primarily at the deep end of the truck trailer van body. The loading dock spot light of the present invention with its short body design helps prevent fork trucks from hitting and destroying it. The overall short body of the light structure is designed to stay out of the primary main path of the fork truck traffic, allowing the light emitted from the light bulb to just peek beyond the loading dock door seal edge. The present invention is a simple mechanical device, which reduces loading dock operator confusion during loading and unloading operation, maintenance, and repair.

The standard loading dock lights for loading and unloading tractor trailer vans usually have long cumbersome arms and get damaged easily in heavy traffic areas at loading dock facilities. Loading dock lights with arms, elbows or extensions break in usage over time. They are costly to keep repairing, costly with the down time of no light when broken and get in the way of the forklift, forklift driver and payload. The short body pipe mount and door jamb loading dock spot light is an economical alternative. The standard loading dock lights for loading and unloading tractor trailer vans usually have long cumbersome arms and get damaged easily in heavy traffic areas at loading dock facilities. Many loading dock spot lights have been developed to light a tractor trailer van or other vehicles.
For example, U.S. Pat. No. 5,709,458 discloses a dock light. This invention requires a powered cooling fan to prevent the unit from overheating. It is also extensible by means of a gooseneck arrangement. Such an arrangement can be susceptible over time to wear and the effects of gravity. The present invention does not use such a system.
U.S. Pat. No. 5,357,414 discloses a modular cantilevered electrical light fixture. The nature of a cantilevered light is susceptible over time to wear and the effects of gravity. The present invention does not use such a system.
U.S. Pat. No. 4,973,016 discloses a dock fan and light cantilever-mounted articulated multi-arm utility support assembly. As in the prior inventions, a cantilevered light is susceptible over time to wear and the effects of gravity. The present invention does not use such a system.
U.S. Pat. No. 5,258,898 discloses an electrical lighting support assembly. As in the prior inventions, a cantilevered light is susceptible over time to wear and the effects of gravity. The present invention does not use such a system.
U.S. Pat. No. 4,880,193 discloses a less than 360 degree lamp swivel. This invention describes a swivel which connect two or more articulated swing arms mounted to a fixed structure on one end with a lamp on the other end. As described herein, such an arrangement is susceptible over time to damage, wear, and the effects of gravity. The present invention mounts directly to a solid structure, which renders it less vulnerable to damage and wear.
U.S. Pat. No. 4,726,552 discloses a lamp swivel. Again, this invention describes articulated cantilevered arms which will droop over time, and are more vulnerable to external damage than is the present invention
U.S. Pat. No. 4,319,314 discloses a light fixture with internal connection zone. This invention is concerned with means to connect internal lamp wiring in a tubular, extended arm.
U.S. Pat. No. 4,814,955 discloses a swivel device for mounting a spotlight. This invention is limited to a bidirectional swivel mount for a light, not specific to a loading dock.
U.S. Pat. No. 5,213,413 discloses a combined light and light support bracket. This invention uses an articulated support arm with a junction box and switch arrangement mounted near the light fixture itself. This invention is highly susceptible to damage from fork lift trucks and the like.


A premix burner is provided, with a swirl generator and a downstream mixer tube for combusting gaseous and liquid fuel which during entry of combustion air is introduced into the burner interior space of the swirl generator and/or is introduced into the burner interior of the swirl generator on a burner axis, and also with a fuel lance which is arranged on the burner axis. The premix burner, in the transition section from the swirl generator to the mixer tube, includes at least one additional feed for introducing gaseous and/or liquid premix fuel from the wall region into the burner interior space of the mixer tube.

Burners for combusting liquid and/or gaseous fuels, especially for use in a gas turbine, are known, which on the one hand have a high stability during operation, and on the other hand have good characteristics with regard to NOx values.
Thus, the so-called EV burner became known from EP-A1-321809. The premix burner which is described there is a conical burner which comprises a plurality of shells, a so-called double-cone burner, for creating a closed swirled flow in the cone head, which flow, on account of the increasing swirl along the cone point, becomes unstable and changes into an annular swirled flow with backflow in the core. Fuels, such as gaseous fuels, are injected along the passages which are formed by the individual adjacent shells, —also referred to as air inlet slots, and are homogeneously intermixed with air, before combustion commences as a result of ignition at the stagnation point of the backflow or backflow bubble, which fulfills the function of a device-free flame retainer. Liquid fuels are preferably injected via a central nozzle at the burner head and then evaporate in the cone cavity. A further important development in the field of premix burners involves the so-called AEV burner, as is known for example from EP-A1-704 657. The proposed burner has a swirl generator on the head side, which uses the aerodynamic basic principles of the EV burner which is already described above, for example according to EP-A1-0 321 809. This swirl generator is arranged upstream of a mixing section, the construction of which is explained in more detail further below. In principle, however, the use of an axial or radial swirl generator is also possible. Furthermore, it is also possible to provide a swirl generator which comprises a cylindrical or virtually cylindrical tube in which air flows into the inside of the tube via similar longitudinal slots, as in the case of the EV swirl generator, wherein the desired swirl formation of the air is carried out by means of a conically extending inner body for maximizing the sought-after premixing with a fuel which is injected at a suitable point, wherein this inner body conically tapers in the flow direction, with which the requirements for an efficient swirled flow are also provided in this case. Both the embodiments for the swirl generation which are referred to here, and the said printed publications, are an integrating element of this description. The mixing section itself preferably comprises a tubular mixing element, —subsequently referred to as a mixer tube, which permits a perfect premixing of the fuel, or fuels, which is or are used. The flow from the swirl generator in this case is transferred smoothly into the mixer tube. This takes place as a result of a transition geometry which comprises transfer passages which form the head part of this mixer tube, and which, as already indicated, transfer the flow into the adjoining effective throughflow cross section of the mixer tube. This loss-free, per se, flow guiding between swirl generator and mixer tube first of all prevents the direct formation of a backflow zone at the outlet of the swirl generator. Initially, the swirl intensity in the swirl generator is selected via its geometry so that the breaking up of the vortex does not take place in the mixer tube but further downstream at the combustion chamber inlet, wherein the length of this mixer tube is dimensioned so that a satisfactory mixing quality for all fuel types results. If, for example, the swirl generator which is used is constructed according to the principle features of the double-cone burner, then the swirl intensity results from the design of the corresponding cone angle, of the air inlet slots, and their number. In the mixer tube itself, the axial velocity profile has a distinct maximum on the axis and consequently prevents flashbacks in this region. The axial velocity decreases towards the wall. In order to also prevent flashbacks in this region, provision is made for various measures. For example, for one thing the overall velocity level can be raised by using a mixer tube with a sufficiently small diameter. Another possibility is to increase the velocity only in the outer region of the mixer tube by a small portion of the combustion air flowing into the mixer tube via an annular gap or through film layer holes downstream of the transfer passages.
Provision is frequently made in such burners for a plurality of fuel injection nozzles which are arranged in groups in order to thus ensure a stable combustion in different load ranges, for example special pilot nozzles for the low load range. In this case, the flame position can shift considerably, depending upon the piloting, and in such a case thermo-acoustic fluctuations can also occur in transition sections as a result of periodic change of the flame front positions.
These thermo-acoustic oscillations constitute a danger for each type of combustion application. They lead to pressure oscillations of high amplitude, to limitation of the operating range, and can increase pollutant emissions. This especially applies to combustion systems with low acoustic damping, such as annular combustion chambers with reverberative walls. In order to enable a high power conversion over a wide operating range with regard to pulsations and pollutant emissions, an active control of the combustion oscillations may be necessary.
In the prior art, as combustion concepts for partial load operation of such burners, for example so-called burner staging is known, in which individual burners are purposefully deactivated so that the remaining burners can be operated at full load. In particular, in the case of annular combustion chambers with a plurality of burner rings of different radius, which are offset in relation to each other, this concept can be used quite successfully.
As a result of fuel staging inside a burner, the flame position can be influenced and therefore influencing of flow instabilities and also time delay effects can be reduced (described for example in EP-A1-1 292 795).
It is also known to provide so-called pilot lances in such burners. Pilot fuel (gaseous or liquid) can be specifically fed centrally via a lance for the piloted operation of the burner, as is described for example in EP-A1-0 778 445 for the case of a double-cone burner, and in WO-A-93/17279 and also in EP-A1-0 833 105 for premix burners without, or with, a downstream mixing section.


A method of coating a component (6) having at least one passage (16) entirely therethrough. The method comprising the steps of applying a coating (28) to a region of the surface (22) of the component (6), adjacent to one end of the passage. Then directing a liquid jet (38) through the other end of the said passage (16) so as to remove at least a portion of any coating material (28) located within, or obstructing, the passage (16). In this method the jet is channelled by a first portion (42) of the passage (16) before it encounters the coating material (28) within, or obstructing, the passage (16). In particular the jet (38) is a water jet, which is used to remove a ceramic coating (28) from a component (6). The method has particular use in clearing cooling holes (16) within combustor components or turbine blades. The method can also be used in the repair of such components (6).

Gas turbine engines operate at extremely high temperatures for increased performance and efficiency. A limiting factor in most gas turbine engine designs, however, is the maximum temperature that various components of the engine can tolerate. One such particular component area which is so limited is the combustion chamber of a gas turbine engine.
One method to increase the maximum allowable temperature and/or decrease the component metal temperature is to provide cooling holes in the walls of the component. These holes allow cool air to flow through and along the walls of the component exposed to the high gas temperatures. As the air flows along the surface of the walls it forms a cool layer. This cool layer reduces the temperature of the wall surface and physically keeps the hot gases from contacting the walls of the component, thereby permitting the component to withstand higher gas temperatures than would otherwise be possible.
Another method of allowing higher gas temperatures to be used is to apply a protective thermal barrier coating to the walls of the component that are exposed to the hot gases. In the case of combustors this is, in particular, the inner walls of the flame tube, the outer walls being exposed to cooler compressor delivery air. Such coatings conventionally comprise, for example a MCrAlY material which offer thermal and corrosion protection. MCrAlY refers to known coating systems in which M denotes nickel, cobalt,iron or mixtures thereof; Cr denotes chromium; Al denotes aluminium; and Y denotes yttrium. A further ceramic layer is also often applied on top of the MCrAlY layer to give improved thermal protection. In such an arrangement the MCrAlY layer acts as a bond coat for the ceramic coating layer. An example of such a ceramic coating material is yttria stabilised zirconia which is applied on top of an MCrAlY layer.
The MCrAlY and ceramic protective coatings are typically applied by physical vapour deposition (PVD), chemical vapour deposition (CVD) or plasma spraying means. Examples of such protective coatings and the methods of applying them are well known and are described in: U.S. Pat. No. 4,321,311, U.S. Pat. No. 5,514,482, U.S Pat. No. 4,248,940 among many others.
Cooling holes and protective coatings can, and are, used in conjunction to allow operation of a component at a high temperature. There are two basic methods for producing such components that have cooling holes and a protective coating. In the first method the coating is applied to the component and then the holes are drilled through the coated component. Examples of this method are described in pending European Patent Application Number 97305454 in which laser drilling is used to penetrate a thermal barrier coating and the metal of the component. A problem with this method is that, by design, the thermal barrier coating is resistant to heating produced by the laser to drill through the material. Consequently drilling of the coating requires a high power laser, a prolonged operation, and results in considerable heating of the surrounding area which can be undesirable. Problems also exist if mechanical drilling techniques are used since the thermal barrier coatings are generally brittle. Mechanical drilling can crack and damage the coating in the region around the holes causing the coating to fall off the component either during the machining operation or prematurely during service.
In the second method holes are drilled in the component and then the coating is applied to the drilled component. This method does not have any of the problems associated with drilling/machining through the coating described above. However application of the coating after the holes have been drilled does tend to at least partially block some or all of the holes. This restricts the flow of cooling air through the holes and can result inadequate cooling of the component producing hot spots, overheating and possible failure of the component. Furthermore the blocking of the cooling holes is unpredictable and so designing the holes to accommodate a degree of blockage is problematic and also, if it is possible will reduce the efficiency of the engine.
Consequently any coating material blocking the cooling holes has to be removed. The problem of cooling hole blockage and a method of removing the coating from a cooling hole is described in EP 0,761,386. According to this patent an abrasive slurry under pressure is directed at the coating on the component. This slurry flows through the cooling holes thereby removing the coating material that is blocking the hole. A similar technique using a high pressure fluid jet is also described in JP 8108400.
A problem with both of these methods of clearing the holes is that the high pressure fluid jet, and the abrasive slurry, as well as removing the coating material from within the hole can also undesirably damage the remainder of the coating on the component. In particular the coating material in the region around the cooling hole is often damaged. This damage to the coating can reduce the coating thickness and/or reduce its adhesion to the component resulting in the coating falling off.
Further problems are that the high pressure fluid, and the abrasive slurry, have to be accurately directed at the specific cooling holes. This requires that the high pressure fluid jet, or abrasive slurry, be accurately controlled and directed. This is however difficult to achieve in a production environment and the machines capable of such accurate control are expensive. An alternative way of accurately directing the abrasive slurry or jet at a particular hole is to use a protective maskant or suitable tooling to mask some of the holes, and possibly the surrounding area of the coating. The mask protects the areas of the component from the jet or abrasive slurry and accurately directs the high pressure fluid or abrasive slurry into the holes. The mask is then removed and applied to a different area and cooling holes in order to clear all of the holes of the component. This process is, however, slow and is not conducive to a production environment. There is also a possibility that if a maskant is used that the maskant may not be fully removed and may itself block the cooling holes. A maskant, or the method of removal of the maskant, may also damage the coating.

Method of unblocking an obstructed cooling passage


An automatic redundancy system may exploit an existing microprocessor management system on chip for carrying out autonomously, without communicating with an external testing machine, the operations of: writing data in the memory array according to one or more pre-established test patterns, verifying data successively read from the memory array, and substituting failed elements of the memory array with equivalent redundancy structures. A logic structure may detect and store memory array failures upstream of the output data path. Thereby, data collection relating to failures may be accomplished more quickly and without any interaction with the testing machine apart from communicating the end of the execution of the redundancy process.

The market for FLASH memory devices offers small margins for manufacturers of memory devices. The industry is studying new manufacturing techniques and methods to improve both yield and productivity. A known technique for increasing yield comprises implementing row, column, and sector redundancy. These techniques, even if they increase the yield, also increase relatively the time used for testing the devices on wafer, for example, Electric Wafer Sort (EWS). This increase in testing time is because the test machine, besides detecting the physical position of the failed element in the array, may implement a series of procedures for mapping the failed element (row, column, sector) onto an available valid spare resource. This may limit productivity, and for improving it, further investments are made for improving the throughput of validated devices.
The devices being fabricated may be usually tested on wafer using techniques, for example, EWS, for determining the presence of failed elements (rows, columns, or whole sectors), and for repairing them by substituting the failed element with spare resources available on chip. As schematically depicted in FIG. 1A, the whole test, substitution, and verification process may be carried out by the test machine establishing communication with each single die in order to: 1. carry out specific tests for determining the presence of eventual failures; 2. store (in the test machine) the position of the failures detected in the memory array of cells; 3. apply the redundancy rules of the particular architecture (written in the software for managing the test machine) used for mapping correctly the failed element on an equivalent spare (redundancy) element; and 4. write in a nonvolatile fashion in the memory under test the information obtained in the previous steps.
This process may have two drawbacks: complex test programs may be developed for carrying out the search of and implementing complex techniques for repairing eventual failures; and the time used by the test machine for testing each single die, for determining eventual failures, and for arranging substitution by spare resources, where it is possible, may be relatively long. This resulting increase in yield due to redundancy may reduce productivity because of testing. It is possible to compensate for this reduction of productivity by buying and installing numerous test machines.
In order to improve productivity, architectures of memory devices that contemplate integrating in the same device dedicated structures for simplifying the operations carried out by the test machine have been disclosed. The prior published European patent application No. EP 1,624,465 "Programmable multi-mode built-in self-test and self-repair structure for embedded memory arrays," in the name of Assignee of the present application, discloses an architecture developed to provide a tool for the analysis of failures that may suggest possible effective modifications of certain process conditions for reducing the number of failures. The article "Programmable Built-In Self-Testing of Embedded RAM Clusters in System-on-Chip Architectures", by A. Benso, et al., IEEE Communications Magazine, September 2003, pages 90 to 97, provides another example of these known approaches.
These known techniques may have the drawback of using integrated complex dedicated structures, such as dedicated processors, for realizing a so-called Built In Self Test (BIST) system or, as in the case of the above mentioned prior application, for realizing a Built In Self Test and Self Repair (BISR) system. The realization of which uses silicon real estate. This may render these architectures unusable on stand alone FLASH memory devices. It may be employed in systems on chip or on complex architectures of chips that include, for commercial purposes, microcontrollers and large volatile memory arrays (RAM). Moreover, these systems may contemplate an interaction with the EWS test machine for collecting verification data when reading the memory and for carrying out redundancy operations and read operations. These operations are carried out for verifying the correct functionality of memory locations and involve the whole data path of the memory device.
On another account, modern nonvolatile FLASH memory devices (even stand alone devices) may include a small microcontroller system for managing operations of the memory, the system comprising a microprocessor and a related ROM storing program codes for executing the various functions. The system may also comprise an internal address counter, one or more auxiliary RAM memory arrays, for example, for managing the protection of sectors and for storing configuration information of the device that are read during the turn on phase, and arrays of CAMs or a reserved sector of the non volatile memory array, inaccessible by the user, in which, during a phase of test on wafer of the device being fabricated, redundancy and configuration information of the inner circuitry and other specific parameters of the device under test are permanently written.

Memory device with fail search and redundancy


A binder for making metallurgical coke and a process for making the binder. The binder is thermally hydrocracked pitch which has been de-ashed. The binder may be mixed with low rank bituminous coal, heated to make coke which is acceptable as a metallurgical coke. The thermally hydrocracked pitch may be de-ashed by mixing with a solvent, and separating the insoluble portions from the soluble portions using a centrifuge. The soluble portions may be separated from the solvent, for example, in a fractionating section, and used as the binder with poor coking coal to make metallurgical coke.

Metallurgical coke has a variety of uses. For example, metallurgical coke can be used for friction materials, for conductive flooring, for foundry coatings, for corrosion materials, for foundry carbon raiser, as a reducing agent, in drilling applications, as ceramic packing media, and for heat-treatment, for oxygen exclusion and electrolytic processes. Metallurgical coke can be also used as a filler coke for poly-granular carbon products.
However, the majority of metallurgical coke is used as a fuel, as well as a reducing agent, for producing iron and steel. More specifically, metallurgical coke is added to iron ore in a blast furnace to produce pig iron which can be processed into other products.
In order to make metallurgical coke, coal is heated in the absence of air, and the coal will soften, plasticize, and then re-solidify into coke. More specifically, coal is fed into coke ovens and subjected to oxygen-free pyrolysis, and heated to approximately 1100° C. This melts the coal and drives off any volatile compounds and impurities to leave pure carbon. The purified, hot, liquefied carbon solidifies into lumps called coke that, for example, can be fed into a blast furnace along with iron ore and limestone to produce pig iron that is further processed to produce steel and steel alloys.
In order to be acceptable as metallurgical coke, the resultant coke must have sufficient stability to support the temperatures, and physical and chemical processes in the blast furnace. Thus, the characteristics and qualities of the coal used to make the coke are important in determining if the coal can be used to make metallurgical coke.
Coal is typically divided into four categories (or ranks): anthracite; bituminous; sub-bituminous; and, lignite. Each type of coal has different sets of physical properties that are based upon a variety of factors. Three of the more relevant factors that impact the coal's physical properties are the moisture, volatile content, and carbon content. Additionally, the levels of sulfur and ash in coal are typically used in determining if the coal is good coking coal. For example, a good coking coal may have a moisture content between 2-15%, a volatile content between 32-36%, a carbon content between 45-85%, and ash content between 3-12% and a sulfur content between 0.7-4%.
Additionally, the Crucible Swelling Number (CSN) (also referred to as Free Swelling Index (FSI)) is one qualitative measurement that can be used to evaluate the properties of the coal. A coal with a low CSN, for example between 0 to 2, is believed to be unsuitable for making metallurgical coke. Additionally, a coal with a high CSN, for example 8 or 9, is also believed to be unsuitable for making metallurgical coke.
If the coal meets the appropriate standards and thus, has acceptable physical characteristics as well as low enough levels of impurities), it is considered "good coking coal" (or "metallurgical coal"). On the other hand however, if the coal does meet one or more of the standards for the good coking coal, it is considered "poor coking coal" (or "non-metallurgical coal") and is not used by itself to make metallurgical coke.
Since good coking coal is both rare and expensive in comparison to poor coking coal, efforts have been made to utilize poor coking coal to produce metallurgical coke. One known method for using poor coking coal to produce metallurgical coke involves mixing the poor coking coal with good coking coal. The mixture typically must provide an acceptable base to acid ratio. The base to acid ratio for the coal is defined as the amount of the basic oxides (Fe2O3, CaO, MgO, K2O, Na2O) divided by the amount of the acidic oxides (SiO2, Al2O3, TiO2). If the resulting mixture has an acceptable base to acid ratio, it can be used to produce metallurgical coke. However, this method still requires the use of good coking coal, which, again is expensive and rare in comparison to poor coking coal.
Another method of using poor coking coal to produce metallurgical coke involves mixing poor coking coal with one or more binders. The binder(s), together with the poor coking coal, can be heated to make a coke that has the appropriate properties associated with metallurgical coke.
Pitch is a viscoelastic polymer that can be derived from a variety of sources and which has been used as a binder with poor coking coal to make metallurgical coke. Pitch can come from a variety of sources, for example, thermal hydrocracking of petroleum residues, petroleum processing by distillation and solvent de-asphalting, and destructive distillation of coal to name a few. The source of the pitch will impact the pitch components (and the pitch properties).
Thermally hydrocracked pitch is readily abundant and comprises a solid waste product from the various reactions of petroleum residues to produce various desirable products like gasoline, diesel, gas oil and other hydrocarbon materials. Typically, thermally hydrocracked pitch comprises a mixture of coke, spent catalyst, and, some heavy hydrocarbons (i.e., hydrocarbons having 20 or more carbon atoms).
While it has been suggested to use neat (i.e., unaltered) thermally hydrocracked pitch as a binder for making metallurgical coke, thermally hydrocracked pitch contains various chemicals and impurities that are or may be undesirable in metallurgical coke.
It would be desirable to provide a process for making a thermally hydrocracked pitch based binder which can be used with poor coking coal to produce acceptable metallurgical coke.

Binder for metallurgical coke and a process for making same