A heating apparatus for heating supply of gaseous fluid 1 heats a relatively low temperature gaseous fluid and feeds a heated supply flow to a high temperature gaseous fluid introduction equipment. The heating apparatus has heat exchangers 11, 12 provided with fluid passages through which the low temperature fluid flow passes, a splitting area 15 for dividing a heated supply flow H of gaseous fluid, which is heated by the heat exchanger, into first and second heated gaseous streams H1, H2, and combustion areas 13, 14 in which a combustion reaction of combustible matter takes place in the existence of the first heated gaseous stream. The heated supply flow or the first stream is introduced into the combustion area and the combustible matter is fed thereto, and the combustion area causes the combustion reaction of combustible matter in the existence of the heated supply flow or the first stream. Hot gas produced by the combustion reaction is exhausted through the heat exchanger. The heat exchanger has a regenerator which accumulates heat in its heat-transferable contact with the hot gas and emits the heat in its heat-transferable contact with the low temperature gaseous fluid. The heating apparatus heats or preheats the low temperature gaseous fluid to a high temperature and feeds the second heated gaseous stream to the equipment.

The present invention relates to heating apparatus and heating method for supply of gaseous fluid, and more particularly, to such apparatus and method in which a relatively low temperature gaseous fluid is heated to a high temperature and a heated supply flow at a high temperature is fed to an equipment, such as a combustion furnace or a combustion equipment to be supplied with high temperature gaseous fluid.
A variety of combustion furnaces or combustion equipments, such as waste incinerator, waste gasification melting furnace, boiler, waste heat recovery boiler, heating furnace, and coal gasification furnace, are practically used in any kind of facilities, e.g., public facility, power generation plant, chemical plant or the like. In general, such a combustion furnace or combustion equipment is provided with a gaseous fluid feeding device for feeding combustion air to a combustion area of the furnace, and the feeding device includes heating means, such as a heat exchanger utilizing the waste heat of the combustion exhaust gas, preheating apparatus or pre-combustor for preheating or causing pre-combustion of combustion air. The heating means heats or preheats intake air or combustion air and feed a high temperature air flow or preheated air flow to a combustion means or firing means such as a burner.
FIG. 34 is a schematic flow diagram generally illustrating an arrangement of a waste gasfication melting furnace provided with such heating means.
A furnace 6 constituting a waste gasfication melting furnace is connected to an intake system with a forced draft fan 102 and a heating device 101, and an exhaust system 7 including a cooling device 71, a flue gas treatment system 72 and a stack 73. The system 7 is, in general, equipped with a series of exhaust gas treatment means, such as a dust collector and a exhaust gas denitration device. In the furnace 6, a melting furnace region 60 with a molten waste fluidized zone 61 in its bottom part, and an upper secondary combustion region 62 above the region 60.
The furnace 6 has a waste inlet opening 63 for charging waste into the region 60 and a secondary material inlet opening 64 for supplying supplementary materials and fuel thereto, the opening 63 being connected to conveying means 66 through a shute 65 and a feeder (not shown) and the opening 64 being connected to a supplementary material feeder (not shown) by a conveyor 67.
In the region 60, a plurality of burner throats 50, 51, 52 are provided below the openings 63 and the conveyor 67. The primary throat 50 in the zone 61 is joined to a heating device 101 through the preheated air supply line HA. Pre-combustion or primary combustion of intake air induced through an inlet 103 and the fan 102 is carried out in the device 101, which feeds high temperature preheated combustion air to the throat 50 through the line HA.
Combustion apparatus provided with such kinds of air heating apparatus permits the oxygen density or excess air ratio of the preheated air to decrease, owing to the pre-combustion or primary combustion. In order to compensate for the reduction of the oxygen density and to ensure a desired combustion reaction in the furnace, the heating device 101 is provided with an oxygen supply line 104 joined to the line HA. The line 104 is connected to an oxygen source 105 having oxygen cylinders, which adds a predetermined flow rate of oxygen (O2) to the preheated air flow through the line HA.
Provision of an oxygen feeder, however, results in an increase of initial construction costs for the furnace or combustion equipment, as well as complication of maintenance of the system. Further, such an expensive oxygen cylinder or the like has to be periodically supplied to the oxygen feeder. Thus, since routine maintenance is necessitated for the oxygen feeder, costs for running and maintaining the system is increased. This is undesirable for practical use in long years.
Research and development as regards a variety of coal firing apparatus, Such as coal fired power generation boiler, pulverized coal firing boiler and coal gasification system, and various types of coal fired combined cycle power generation systems, such as AFBC, PFBC or pressurized CPC, are widely conducted in recent years in response to political or social requirements. In general, these kinds of coal fired systems or equipments are provided with heating devices, such as a heat exchanger using waste heat of combustion exhaust gas, which heat or preheat combustion air of ambient atmosphere to an appropriate temperature and feed the preheated air to combustion means such as a burner for pulverized coal.
Various types of coal fired devices are known, e.g., stoker combustion type, pulverized coal fired type, fluidized bed type and so forth. In general, the pulverized coal fired type of boiler is preferably adopted as a coal fired boiler in with a large capacity, such as a boiler of power generation station, since such type of boiler presents relatively good response and controllability as to variation of load and effects a desirable combustion efficiency.
In such a pulverized coal fired boiler, coal particles are carried with primary air into a combustion area and rapidly heated by a burner for pulverized coal. As combustion exhaust gas of the boiler contains a relatively large amount of fuel NOx, thermal NOx, sulfur and smoke dust (dust, fly ash), an exhaust system is generally equipped with a series of desulfurizer, denitration device, and electrostatic precipitator (ESP) and so forth.
FIG. 35 is a schematic flow diagram illustrating such a coal fired system.
A coal fired power generation boiler plant comprises a burner for pulverized coal 120 and a pulverized coal fired boiler 110, and the burner 120 is connected with a pulverized coal feeding line CS and a secondary air feeding line CA. The line CA is connected to a forced draft fan 121 through a heating section 181 of a rotary air-preheater APH for heating the secondary air to an order of 300xc2x0 C. The fan 121 feeds intake air from an air intake port 122 and an air intake line OA to the preheater APH and the air preheated thereby is fed to the burner 120 through the line CA. The pulverized coal and air mixed in the burner 120 fires in a combustion area 150 of the boiler 110 to heat superheater 151, reheater 152 and economizer 153 in the area 150, and combustion gas is exhausted through an exhaust gas line E11. The exhaust system including lines E11 to E20 is equipped with exhaust treatment devices wherein electrostatic precipitator (ESP) 171, ammonia injector 172 connected to an ammonia source (not shown), selective catalytic reduction device 173 with catalyst units, heat accumulating section 174 of a rotary air preheater APH for heat recovery, forced induce fan 175, heat accumulating section 176 of a gas-gas heater GGH, booster fan 177, desulfurizer 178, heat emission section 179 of the gas-gas heater GGH, and stack 180 arranged in series.
A high-cycle regenerative combustion system which is capable of preheating such a supply flow of air to the combustion equipment is disclosed in Japanese patent application No. 5-6911 (Japanese patent laid-open publication No. 6-213585) of the present applicant. This system developed by the present applicant includes a regenerator of honeycomb structure with a number of narrow channels or fluid passages which exhibits a high temperature effectiveness and a high volumetric efficiency. High temperature combustion exhaust gas and low temperature supply fluid flow alternately passes through the regenerator, so that the supply flow is heated to a high temperature above 800xc2x0 C. by heat exchange with the exhaust gas through the regenerator.
However, in this kind of system, high temperature combustion exhaust gas effluent immediately after a combustion step has to be introduced into the regenerator, since the high temperature gas possessing sensible heat enough to be efficiently transferable to the low temperature supply flow. Therefore, it would be difficult to apply the conventional regenerative heat exchange system to the aforementioned waste gasification melting furnace or the like, in which the high temperature exhaust gas cannot be readily used.
Further, the fluid passages of the honeycomb regenerator of the above regenerative system is apt to be relatively easily blocked by dust, smoke dust, ash, fly ash or the like, and therefore, relatively clean combustion exhaust gas at a high temperature, which does not contain dust or other foreign matters, should be introduced into the honeycomb regenerator. Therefore, it would be difficult to effectively use such a regenerator in a combustion system which may produce combustion exhaust gas containing dust, ash or other foreign matters.
For instance, high temperature exhaust gas of coal fired combustion equipment includes a substantial quantity of smoke dust, and therefore, the narrow channels of the regenerator are apt to be blocked in a relatively early stage. Therefore, it would be difficult to apply the aforementioned regenerative system to an exhaust system of a coal fired equipment. Thus, it is necessary to develop a heat exchange system applicable to such kinds of combustion equipments.
It is therefore an object of the present invention to provide a heating apparatus and a heating method for heating supply of gaseous fluid which heats a relatively low temperature gaseous fluid and feeds a heated supply flow to a high temperature gaseous fluid introduction equipment, wherein the supply flow can be heated to a high temperature without substantially changing the property of the supply flow, such as its oxygen density.
Another object of the present invention is to provide such an apparatus and method which enable the supply of gaseous fluid for combustion to be heated to a high temperature range above 800xc2x0 C., preferably, above 1,000xc2x0 C.
Still another object of the present invention is to provide such apparatus and method which is capable of producing water gas and which can continuously feed a water gas flow to an equipment consuming the water gas, such as a coal gasification system or a gas turbine plant.
To this end, the present invention provides a heating apparatus for supply of gaseous fluid which heats a relatively low temperature gaseous fluid and feeds a heated supply flow to a high temperature gaseous fluid introduction equipment, which comprises a heat exchanger provided with a fluid passage through which the low temperature gaseous fluid flow passes and adapted to heat the low temperature gaseous fluid, a splitting area for dividing a heated supply flow of the gaseous fluid into first and second gaseous streams, the supply flow having a temperature raised as a result of its passing through said heat exchanger, and a combustion area into which combustible matter is introduced so that a combustion reaction of the combustible matter takes place therein. The heat exchanger, combustion area and splitting area are in communication with each other, so that the second stream is fed to the above equipment, and the hot gas produced by said combustion reaction in the combustion area is exhausted through the heat exchanger. The heat exchanger accumulates heat in its heat-transferable contact with the hot gas and emits the heat in its heat-transferable contact with said low temperature gaseous fluid.
According to the arrangement of the present invention, the hot gas produced in the combustion area passes through the fluid passage of the regenerative heat exchanger to heat it. The hot gas is cooled by the heat accumulating action of the heat exchanger in which the sensible heat of the hot gas is heat-transferred or transmitted to the regenerator and stored therein, whilst the low temperature fluid is heated to raise its temperature with the heat emitting action of the heat exchanger in which the sensible heat stored in the regenerator is transferred to the low temperature fluid to heat it. Thus, the heat exchange between the low temperature flow and the hot gas effected by means of the regenerator allows the low temperature flow to be heated or preheated to a high temperature.
The present invention also provides a heating method for heating supply of gaseous fluid in which a relatively low temperature gaseous fluid is heated and a heated supply flow is fed to a high temperature fluid introduction equipment, comprising first and second heating processes. The first heating process includes steps of introducing the low temperature gaseous fluid through a first heat exchanger at a high temperature so as to heat the low temperature gaseous fluid tip to a high temperature with a heat exchange action in its heat transferable contact with the first heat exchanger, splitting the heated supply flow into first and second gaseous streams, feeding the second stream to the equipment, generating a combustion reaction of the heated supply flow and/or the first stream in a combustion area, introducing hot gas produced by the combustion reaction into a second heat exchanger, and exhausting the hot gas therethrough so that sensible heat of the hot gas is accumulated in a regenerator of the second heat exchanger with a heat exchange action in a heat transferable contact between the hot gas and the second heat exchanger. The second heating process includes steps of introducing the low temperature gaseous fluid through the second heat exchanger at a high temperature so as to heat the low temperature gaseous fluid up to a high temperature with a heat exchange action in its heat transferable contact with the second heat exchanger, splitting the heated supply flow into the first and second gaseous streams, feeding the second stream to the equipment, generating a combustion reaction of the heated supply flow and/or the first stream in the combustion area, introducing hot gas produced by the combustion reaction into the first heat exchanger, and exhausting the hot gas therethrough so that sensible heat of the hot gas is accumulated in a regenerator of the first heat exchanger with a heat exchange action in a heat transferable contact between the hot gas and the first heat exchanger, The first and second heating processes are alternately changed over in a predetermined time interval so that the low temperature flow is continuously heated to the high temperature.
From another aspect of the present invention, this invention provides a heating system for heating a supply of gaseous fluid comprising a plurality of the above heating apparatus arranged in parallel.
From still another aspect of the present invention, a preheating apparatus for preheating combustion air for a combustion furnace, a deodorization apparatus for exhaust gas, a repowering apparatus for exhaust gas of a turbine, a water gas generator, or an inert gas heating apparatus are provided, each having the above described apparatus for heating the supply flow of gaseous fluid.
In a preferred embodiment of the present invention, the first stream is introduced into the combustion area, and the combustible matter generates the combustion reaction in the existence of the first stream and maintains the combustion. The low temperature fluid can be substantially heated to a high temperature range equal to or higher than 800xcx9c1,000xc2x0 C. by the substantially direct heat transmission of the regenerator, with the properties of the fluid, such as its initial oxygen density being kept.
In accordance with another preferred embodiment of the present invention, the heated supply flow is introduced into the combustion area, and the combustible matter generates and maintains the combustion reaction in the existence of the heated supply flow. Thus, the low temperature fluid can be heated to a high temperature range equal to or higher than 800xcx9c1,000xc2x0 C. by the substantially direct heat transmission through the regenerator and the heated flow can take the combustion reaction in the combustion area.
According to a preferred embodiment of the present invention, the apparatus may be provided with a fluid flow introduction passage for receiving the low temperature gaseous fluid flow, a combustion exhaust gas passage for exhausting the hot gas effluent, a heated supply flow delivery passage for delivering the second gaseous stream to the gaseous fluid introduction equipment, changeover means connected to the introduction passage and the combustion exhaust gas passage, first and second fluid flow passages connected to the changeover means, first and second heating devices connected to the first and second fluid flow passages, and the splitting area which is in communication with the first and second heating devices and in communication with delivery passage. The first heating device may have the first heat exchanger connected to the first fluid flow passage and the first combustion area arranged in series with the first heat exchanger, wherein the first fluid flow passage, the first heat exchanger and the first combustion area are in communication with each other so as to direct the heated supply flow to the splitting area. Similarly, the second heating device may have the second heat exchanger connected to the second fluid flow passage and the second combustion area arranged in series with the second heat exchanger, wherein the second fluid flow passage, the second heat exchanger and the second combustion area are in communication with each other so as to direct the heated supply flow to the splitting area. The splitting area is preferably provided with splitting means for splitting the heated supply flow into the first and second gaseous fluid streams and directing the first stream to the first or second combustion area. Further, each of the first and second combustion areas are preferably provided with combustion means for generating the combustion reaction of the combustible matter and maintaining the combustion reaction in a predetermined period of time.
In such a preferred embodiment, the combustion exhaust gas in the combustion area passes through the fluid passages of the regenerator of the first or second heat exchanger so as to heat the regenerator. Tile switching control with respect to the changeover means is conducted in a predetermined time interval, so that the heat accumulation action and the heat emission action are alternately repeated in a short term of time, whereby the sensible heat processed by the combustion exhaust gas in the combustion area is transferred and transmitted to the regenerator and accumulated therein during the heat accumulation action, and the sensible heat stored in the regenerator is dissipated to the low temperature fluid to be heated during the heat emission. As the result, the heat exchange action between the low temperature fluid and the combustion exhaust gas is successively carried out by the regenerator, so that the low temperature fluid can be heated to a high temperature equal to or higher than 800xcx9c1,000xc2x0 C. by the substantially direct heat exchange therebetween through the regenerator.
Preferably, the changeover means takes a first position in which the introduction passage is in communication with the first fluid flow passage and the combustion exhaust gas passage is in communication with the second fluid flow passage, and a second position in which the introduction passage is in communication with the second fluid flow passage and the combustion exhaust gas passage is in communication with the first fluid flow passage. The changeover means is adapted to be alternately switched to either of the first and second positions in a predetermined time interval. The combustion exhaust gas is delivered through the regenerator of the first heat exchanger to the first fluid flow passage, while the combustion means of the first combustion area is in a combustion operation in the second position of the changeover means. On the other hand, the combustion exhaust gas is delivered through the regenerator of the second heat exchanger to the second fluid flow passage while the combustion means of the second combustion area is in a combustion operation in the first position of the changeover means. More preferably, the changeover means is alternately switched to either of first and second positions in a predetermined time interval set to be no longer than 60 seconds, preferably no longer than 30 seconds, so that each of the regenerators of the first and second heat exchangers repeatedly perform heat accumulation and heat emission in correspondence with the time interval to heat the low temperature fluid and cool the combustion exhaust gas.
The splitting may divide the heated flow into the first and second streams by control of fluid pressure (control of static pressure and/or dynamic pressure). The splitting means defined by an orifice or restriction can effect a function to control fluid pressure balance of the heating devices and a function to control direction of the first and second streams. In a preferred embodiment, the splitting area is provided with a fluid passage inclined to the center axis of the heating device, and regulation and resistance means positioned in the inclined passage for regulating the direction of the flow and increasing pressure loss of fluid flow. This means may be a honeycomb structure which is substantially the same as the structure of the regenerator.
In a preferred embodiment, the heating apparatus comprises a fuel feed line for introducing a fuel into the combustion area and fuel control means for controlling the fuel feed line. The fuel may be combustible exhaust gas of a combustion furnace. The hydrocarbon fuel or the combustible exhaust gas is alternately introduced into the combustion areas to cause the combustion reaction therein.
The heating apparatus may be provided with first and second exhaust gas introduction passages for introducing combustion exhaust gas, which is produced in a combustion furnace or combustion equipment, into the combustion area, and control valve means for controlling the flow of the introduction passages.
Preferably, the first and second heating devices are arranged in parallel and in communication with each other through a communication passage defining said splitting area. The communication passage is provided with a constriction functioning as an orifice regulating a fluid pressure of said heated supply flow and act as a deflector directing the fluid in an inlet opening of the heated supply flow passage.
In one preferred embodiment of the invention, odorous exhaust gas of painting process or the like, in which odorous components or odorous matters are contained, is alternately introduced into the first and second combustion areas through odorous exhaust gas introduction means so as to take a thermal decomposition reaction therein for deodorizing the odorous gas.
In another preferred embodiment of the invention, the low temperature fluid essentially consists of ambient atmospheric air or inert gas, and the second stream heated to a high temperature of at least 800xc2x0 C., preferably a temperature equal to or higher than 1000xc2x0 C., is delivered to a combustion furnace or a combustion equipment as being a combustion air flow or an inert gas flow at a high temperature.
In still another preferred embodiment of the invention, exhaust gas of a turbine is alternately introduced into the first and second combustion areas and the second stream is directed to a waste heat recovery boiler defining the high temperature gaseous fluid introduction equipment.
According to a preferred embodiment of the invention, the regenerator is a ceramic honeycomb structure having a number of fluid passages or channels through which the low temperature fluid and the exhaust gas of the combustion area alternately pass. The regenerator may have channels defined by cell holes of a square or triangular cross-section, and the thickness and of the cell wall are pitch preferably corresponds to the dimensions ensuring the maximum value of the volumetric efficiency and the temperature effectiveness ranging from 0.7 to 1.0. More preferably, the thickness of the cell wall is no greater than 1.6 mm and the pitch thereof is no greater than 5.0 mm.
In a preferred embodiment of the invention, combustion assist air is additionally introduced into the combustion areas through assist air feeding means so as to supplement or compensate the combustion air required for the combustion reaction in the combustion area. The assist air promotes the combustion reaction so that substantially complete combustion can be achieved in the combustion area and the heat sufficient for the heat exchange with the low temperature fluid can be obtained.
In a preferable embodiment of the invention for production of water gas, the heating apparatus comprises a superheated steam introduction passage for feeding superheated steam as the low temperature gaseous fluid, an exhaust gas passage for exhausting the hot gas produced in the combustion area, changeover means connected to the introduction passage and the exhaust gas passages, first and second fluid flow passages connected to the changeover means, first and second heating devices connected to the first and second fluid flow passages, and a water gas delivery passage to be in communication with the first and second heating devices. The first heating device is provided with the first heat exchanger connected to the first fluid flow passage and the first combustion area arranged in series with the first heat exchanger, and the second heating device is provided with the second heat exchanger connected to the second fluid passage and the second combustion area arranged in series with the second heat exchanger. The first and second combustion areas are provided with combustion means for feeding oxidizer and hydrocarbon fuel to the superheated steam heated by heat exchanges. The first and second heat exchangers heat the superheated steam to a high temperature so that the water gas reaction of the high temperature steam takes place in the heat exchangers and the combustion areas. Tile water gas thus produced is split into the first and second stream in the splitting gas, and the second stream is fed to a water gas consuming device such as a coal gasification device or a power generation system. The first stream is directed into the other combustion area to take a combustion reaction in the existence of the oxidizer and fuel to produce a high temperature gas, which is discharged through the heat exchanger. Tile sensible heat of the gas is accumulated in the regenerator.
In a preferable embodiment of the invention for coal fired gasification process, a low temperature combustion air fed to a coal fired combustion device or a pulverized coal fired boiler is introduced into the heating apparatus, in which the combustion air is heated by the heat exchanger at a high temperature. The apparatus feeds a second stream at a high temperature to the coal fired device. Combustion exhaust gas of the coal combustion device containing combustible matters is introduced into the combustion area of the heating apparatus to be mixed with the first stream at a high temperature, so that a secondary combustion reaction of the exhaust gas is caused therein. The secondary combustion exhaust gas produced by the secondary combustion reaction is exhausted through the heat exchanger. Tile sensible heat of the secondary combustion exhaust gas is accumulated in the regenerator by heat exchange therewith. The first and second heating processes are alternately carried out in a predetermined time interval, so that the low temperature supply air is continuously heated to the high temperature range by heat exchange between the coal combustion exhaust gas and combustion air though the regenerator. Thus, the preheated air at a high temperature is introduced into the combustion device.
In a preferred embodiment of the present invention, the coal combustion device is a pulverized coal boiler and the combustible exhaust gas thereof contains unburnt fuel components, hydrogen and carbon. The preheated air is heated tip to a temperature above the self-ignition temperature of the combustible components and the combustion exhaust gas is alternately fed to the first and second combustion area to be mixed with the first stream therein, thereby taking a secondary combustion reaction.

Heating apparatus and heating method for supply of gaseous fluid


A semiconductor memory device is capable of transferring address signals at high speed and improving the operation reliability even though an input rate of an address signal increases, and thus a degradation of an operation speed caused by applying a bus inversion scheme can be prevented and power consumption can be reduced. The semiconductor memory device includes a bus inversion decoding block configured to determine whether a plurality of address signals are inverted or not by decoding an indication control signal, and an address buffer block configured to receive two address signals per one cycle of an external clock, align the received address signals for parallel processing, and transfer the address signals or inverted address signals according to an output of the bus inversion decoding block.

The present invention relates to a high-speed semiconductor memory device, and more particularly to a semiconductor memory device operating with an address to which a bus inversion scheme is applied.
In a system with a variety of semiconductor devices, a semiconductor memory device serves as data storage. The semiconductor memory device outputs data corresponding to addresses received from a data processor, e.g., a central processing unit (CPU), or stores data received from the data processor into unit cells selected by addresses inputted together with the data.
As the operating speed of the system is increasing, the data processor requires the semiconductor memory device to input and output data at higher speed. To this end, internal circuits of the semiconductor memory device must be able to operate at high speed and transfer signals or data therebetween at high speed.
The operating speed of the semiconductor memory device can be increased by performing internal operations at higher speed or increasing the signal and data input/output speed. As one example, a double data rate (DDR) memory device can increase the data output speed by outputting data in synchronization with a falling edge as well as a rising edge of a system clock. Since the DDR memory device inputs and outputs two data per clock cycle via one input/output terminal in one cycle, its data input/output speed is faster than that of the existing semiconductor memory device. Recently, a semiconductor memory device capable of inputting or outputting four data in one cycle of a system clock was proposed. Although the data input/output speed of the semiconductor memory device is gradually increasing, an input/output speed of an address or command signal is unsatisfactory.
In a typical semiconductor memory device, an address is inputted together with an external operation command signal in synchronization with a rising edge of a clock. That is, the semiconductor memory device receives external address and operation command signal in synchronization with a rising edge of an external clock and performs an internal operation. However, as the operating speed of the semiconductor memory device is increasing, an address can be inputted two times in one cycle of the system clock.
Graphics double data rate version 5 (GDDR5) memory devices for graphic works are designed to receive addresses at a rising edge and a falling edge of an external clock. That is, the GDDR5 memory devices can receive the addresses two times in one cycle of the external clock. Thus, compared with the typical semiconductor memory device, the number of address pins is reduced or the operating speed can be increased by connecting extra pins to a power voltage terminal or a ground terminal. Since an external operation command signal is still inputted in synchronization with a rising edge of an external clock, the address input speed is two times faster than a command input speed.
Since the addresses are inputted two times in one cycle of the external clock, the address transition increases two times and a voltage toggling often occurs at the address input port, causing a lot of current consumption. As one example, a swing width of an address signal can be defined in a range from VIH(Vref+0.12V) at a logic high level to VIL(Vref−0.12V) at a logic low level. Therefore, if the transitions occur two times more than the conventional art, the power consumption will also increase.
As the signal input speed increases in the same time, a bus inversion scheme is applied to the semiconductor memory device in preparation for the increasing transitions. According to the bus inversion scheme, a previously transmitted value and a current value to be transmitted are compared with each other. When transitions occur more than half of a total bit number to be transferred, a signal transmitter transmits an inverted value of the current value to be transmitted, and a signal receiver recognizes the current value by inverting the received signal. On the other hand, when transitions occur less than half of the total bit number, the signal transmitter transmits the current value and the signal receiver recognizes the received signal as it is. At this point, the signal transmitter and the signal receiver additionally transmit indication control signals indicating whether they transmit the current value or its inverted value.
A case where the bus inversion scheme is applied to 8-bit bus will be described in more detail. For example, assuming that "00011100" is a previously transmitted signal and "00001010" is a current value to be transmitted, a transition should occur at 3 bits. In this case, since three bits of the total eight bits have only to be changed, the signal transmitter transmits the current value to be transmitted. If a value to be newly transmitted after the transmission of "00001010" is "11100111", transmission should occur at six bits. In this case, transitions occur more than half of the total eight bits, thus increasing the power consumption. Therefore, using the bus inversion scheme, the signal transmitter inverts the values "11100111" to be transmitted, and transmits "00011000". The signal transmitter activates the indication control signal and indicates that the transmitted value is the inverted value. In this manner, compared with the previously transmitted value "00001010", transitions occur at 2 bits of the eight bits. Consequently, the power consumption can be reduced, compared with the case where the transitions occur at six bits.
If such a bus inversion scheme is applied to multi-bit address signals inputted from the outside, an address input rate is increasing and the power consumption is reduced. However, when carrying out the bus inversion scheme, an operation speed may be lowered, or an operation margin for internal operation may be reduced, degrading the whole operation stability of the semiconductor memory device. In particular, if a delay occurs in the input of the address signal, an operation of reading data from or writing data to a cell corresponding to an address signal becomes slow, degrading the performance of the semiconductor memory device.

Semiconductor memory device using bus inversion scheme


This invention is a solution process for the preparation of ethylene-xcex1-olefin-diolefin copolymers comprising contacting ethylene, one or more xcex1-olefin monomer, and one or more cyclic diene monomer, with a catalyst composition comprising a bridged, bis(cyclopentadienyl) zirconium compound having an unsubstituted cyclopentadienyl ligand, a multiply substituted cyclopentadienyl ligand, said ligands bridged by a covalent bridging group containing one or more Group 14 element, and two uninegative, activation reactive ligands and a catalyst activator compound. The invention process exhibits high catalyst activity, high comonomer incorporation and high diene monomer conversion rates and is particularly suitable for the preparation of elastomeric ethylene-propylene or ethylene-propylene-diene monomer elastomers.

This invention relates to the preparation of ethylene-xcex1-olefin polymers under solution polymerization conditions using catalyst compositions based on biscyclopentadienyl derivatives of zirconium.
Polymers comprising ethylene and at least one or more xcex1-olefin and optionally one or more diolefin make up a large segment of polyolefin polymers and will be addressed for convenience as xe2x80x9cethylene-xcex1-olefin-diolefin copolymersxe2x80x9d herein. Such polymers range from crystalline polyethylene copolymers to largely amorphous elastomers, with a new area of semi-crystalline xe2x80x9cplastomersxe2x80x9d in between. In particular, ethylene-xcex1-olefin-diolefin elastomers are a well established class of industrial polymers having a variety of uses associated with their elastomeric properties, their thermo-oxidative stability, their solubility in hydrocarbon oleaginous fluids, and their capability for modifying the properties of polyolefin blends. Included in this terminology are the commercially available EPM (ethylene-propylene monomer) and EPDM (ethylene-propylene-diene monomer) rubbery polymers, both being vulcanizable by cross-linking, the addition of the diolefin, also known as diene monomer, providing increased ease of both cross-linking and functionalization.
Commercially prepared ethylene-xcex1-olefin-diolefin elastomers have been traditionally been made via Ziegler-Natta polymerization with homogenous catalyst compositions largely based on vanadium or titanium. Newer metallocene catalyst compounds have received attention due to their ease of larger monomer incorporation and potential increases in polymerization activities. U.S. Pat. No. 5,324,800 describes metallocenes having substituted and unsubstituted cyclopentadienyl ligands which are suitable for producing high molecular weight olefin polymers, including linear, low density copolymers of ethylene with minor amounts of xcex1-olefin. WO95/277147 describes bridged and unbridged Group 4 metallocene compounds wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms. These compounds are said to be useful for ethylene copolymerization and propylene polymerization, including elastomeric copolymers of ethylene, xcex1-olefins and non-conjugated diolefins. Ethylene copolymerization with propylene is reported in examples 28-30 and in Table 3, U.S. Pat. No. 5,543,373 describes bridged metallocenes having two differing xcfx80 ligands which are said to be of high activity. Copolymers of ethylene with 1-olefins and/or one or more diene monomers are produced in a preferred process according to the invention. Example R illustrates an ethylene-propylene-diene terpolymer rubber prepared with dimethylsilanediyl(2-methyl4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl) zirconium dichloride.
Ethylene copolymerization is described in WO 95/27717 with zirconocenes having a Cp cyclopentadienyl group with one or two alkylenic cycles of 4 to 8 carbon atoms and a Cpxe2x80x2 cyclopentadienyl group having up to 4 R substituents. Example 12 illustrates the preparation of isopropyliden(cyclopentadienyl) (2,3-cyclotetramethyleneinden-1-yl) zirconium dichloride. Example 19 illustrates syndiotactic propylene polymerization with this catalyst.
A high temperature solution process for the preparation of ethylene-xcex1-olefin copolymers is described in EP-A-0 612 769. The catalyst compositions are based on bis(cyclopentadienyl/indenyl/fluorenyl) titanocenes/zirconocenes which are combined with an alkyl aluminum compound and an ionizing ionic compound which provides a non-coordinating anion. Asymmetrically substituted catalysts are illustrated. The solution process conditions are described to range from 120 to 300xc2x0 C. at pressures from atmospheric to 200 kg/cm2. In the examples of this process the metallocene compound is reacted with the organoaluminum compound, then reacted with ionizing ionic compound, and subsequently added to the polymerization reactor. High molecular weight polymer is said to be produced at high efficiency.
A high activity supported catalyst suitable for ethylene copolymers is described in U.S. Pat. No. 5,240,894. The catalyst isopropylidene(cyclopentadienyl)(fluorenyl) zirconium dichloride is a preferred metallocene embodiment. Example 10 illustrates an ethylene-propylene copolymerization.
It remains important in industry to develop efficient copolymerization processes, and in particular, those capable of high productivity of polymer per unit weight of catalyst compound.
The invention is a polymerization process for the preparation of ethylene-xcex1-olefin-diolefin copolymers comprising contacting ethylene, one or more xcex1-olefin monomer, and optionally, one or more cyclic diolefin monomer, with a catalyst composition prepared from at least one a catalyst activator and at least one bridged, bis(cyclopentadienyl) zirconium compound having an unsubstituted cyclopentadienyl ligand, a bulky, substituted cyclopentadienyl ligand, said ligands bridged by a covalent bridging group containing one or more Group 14 element, said process conducted in a solution polymerization process. The invention process exhibits high catalyst activity, high comonomer incorporation and high diene monomer conversion rates.
The ethylene-xcex1-olefin-diolefin copolymers of this invention (hereinafter referred to as xe2x80x9cEPCxe2x80x9d) is meant to include copolymers, terpolymers, tetrapolymers, etc. It typically comprises ethylene, one or more alpha -olefins, and optionally, one or more cyclic diolefin monomers; it is typically substantially amorphous, and it will typically have a substantially random arrangement of at least the ethylene and the alpha-olefin monomers. Thus both of ethylene-containing elastomer and plastomer copolymers can be prepared by the invention process.
The EPC capable of preparation in accordance with the invention process generally can have a molecular weight range typically between about 20,000 and up to about 500,000 or higher, more typically between about 60,000 and 300,000 where the molecular weight is number-average (xe2x80x9cMnxe2x80x9d).
Typically elastomeric EPC is xe2x80x9csubstantially amorphousxe2x80x9d, and when that term is used to define the EPC elastomers of this invention it is to be taken to mean having a degree of crystallinity less than about 25% as measured by means known in the art, preferably less than about 15%, and more preferably less than about 10%. The three major known methods of determining crystallinity are based on specific volume, x-ray diffraction, and infrared spectroscopy. Another well-established method, based on measurement of heat content as a function of temperature through the fusion range, is carried out using differential scanning calorimetric measurements. It is known that these independent techniques lead to reasonably good experimental agreement. The degree of randomness of the arrangement of monomers in the EPC elastomeric polymers also affects the crystallinity and is appropriately characterized by the degree of crystallinity.
Additionally, it is known in the art that the tendency of a particular combination of catalyst composition and monomers to produce blocky, random, or alternating polymers can be characterized by the product of the reactivity ratios defined for the given monomers under the specific reaction conditions encountered. If this product is equal, to 1.0, the sequence distribution will be perfectly random; the more the product is less than 1.0, the more the monomers will tend to have a xe2x80x9cblockyxe2x80x9d sequence distribution. Generally speaking, the segments of a polymer which crystallize are linear segments of a polymer which have a number of identical (both by chemical make-up and stereo-specific orientation) units in a row. Such segments are said to be xe2x80x9cblockyxe2x80x9d. If there is little or no such sequential order within the segments making up a polymer chain, that chain will be very unlikely to conform itself into the correct shape to fit into the spatial order of a crystal and will accordingly exhibit a low degree of crystallinity. See, xe2x80x9cEthylene-Propylene Copolymers. Reactivity Ratios, Evaluation and Significancexe2x80x9d, C. Cozewith and G. Ver Strate, Macromolecules, Vol. 4, No. 4, 482-4899 (1971). The EPC elastomers of this invention accordingly can be characterized in one embodiment by the limitation that its method for preparation has a reactivity ratio product less than 2.0, preferably less than about 1.5, and more preferably less than about 1.25.
The EPC elastomers of the invention will contain about 10 to about 91 weight percent ethylene, preferably about 20 to 88 weight percent ethylene. The EPC elastomers of the invention preferably contain from 35 to 75 weight percent ethylene.
The xcex1-olefins suitable for use in the preparation of the EPC, or for the polyethylene copolymers, are preferably C3 to C20 xcex1-olefins, but will include higher carbon. number olefins such as polymerizable macromers having up to five hundred carbon atoms, or more. Illustrative non-limiting examples of such xcex1-olefins are one or more of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene. Included in the term xcex1-olefins for the purposes of describing effectively copolymerized monomers are the constrained-ring cyclic monoolefins such as cyclobutene, cyclopentene, norbornene, alkyl-substituted norbornene, alkenyl-substituted norbornene, and the higher carbon number cyclic olefins known in the art, see U.S. Pat. No. 5,635,573, incorporated herein by reference for purposes of U.S. patent practice. The xcex1-olefin content of the EPC ranges depending upon selection of the specific xcex1-olefin. or xcex1-olefins, being more for lower carbon number monomers, for example, about. 10 to about 91 wt. %, preferably about 20 to about 88 wt. % for propylene; and, 5 to 35 mol. %, preferably 7.5 to 25 mol. % and most preferably 10 to 20 mol. % for 1-octene. The EPC elastomers typically have above about 25 mol. % xcex1-olefin incorporation. For the more crystalline polyethylene copolymers the range of comonomer incorporation will typically be below 25 mol. % and more typically below about 15mol. %. In terms of polymer density, the elastomers are typically below about 0.860 g/cm3, and the plastomer ethylene copolymers are from about 0.860 to 0.915.
The diene monomers, or diolefins, useful in this invention include those typically used in known EPDM polymers. The typically used diene monomers are generally selected from the cyclic diolefins having about 6 to about 15 carbon atoms, for example:
A. single ring alicyclic dienes such as 1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and 1,5-cyclododecadiene;
B. multi-ring alicyclic fused and bridged ring dienes such as tetrahydroindene, methyl tetrahydroindene, dicyclopentadiene; bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alklindene, cycloalkenyl and cycloalkylidene norbornenes such as 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbornene, 5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene; and
C. cycloalkenyl-substituted alkenes, such as allyl cyclohexene, vinyl cyclooctene, allyl cyclohexene, vinyl cyclooctene, allyl cyclodecene, vinyl cyclododecene.
Of these, the preferred dienes are dicyclopentadiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene. It will be apparent that a mix of such dienes can also be utilized. The content of the diene monomer in the EPC elastomer can be 0 to about 20 weight percent, and if used, preferably 0.5 to about 15 weight percent, and most preferably about 2.0 to about 12.0 weight percent. Surprisingly, diene incorporation greater than 5.0 wt. %, even greater than 8.0 wt. % is made possible using the process of this invention.
The bridged, bis(cyclopentadienyl) compounds of this invention typically comprise those having ancillary ligands including the unsubstituted cyclopentadienyl ligand, a multiply substituted, bulky cyclopentadienyl ligand, the cyclopentadienyl ligands covalently bridged, and two uninegative, activation reactive ligands at least one of which that can be abstracted for activation of the remaining metal compound to a catalytically active state and one of which is either similarly abstractable or has a "sgr"-bond to the transition metal into which an olefin or diolefin can insert for coordination polymerization.
Thus the bridged, bis(cyclopentadienyl) zirconium compounds of the present invention have the following structure:
where the unsubstituted cyclopentadienyl ring is Cp1, and the substituted cyclopentadienyl ring (Cp2Rn) has at least two non-hydrogen radical substituents R1, wherein each R1 is, independently, a radical selected from:
a) hydrogen radical,
b) hydrocarbyl, silyl or germyl radicals having from 1 to 20 carbon, silicon or germanium atoms,
c) substituted hydrocarbyl, silyl or germyl radicals as defined, wherein one or more hydrogen atoms is replaced by a halogen radical, an amido radical, a phosphido radical, an alkoxy radical, an aryloxy radical or any other radical containing a Lewis acidic or basic functionality,
d) C1-C20 hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from the group consisting of Ge, Sn and Pb,
e) halogen radicals,
f) amido radicals,
g) phosphido radicals,
h) alkoxy radicals, and
i) alkylborido radicals; or
at least two R1 groups are joined together to form, along with the carbon atoms to which they are attached, a C4-C20 ring structure, which is saturated or partially saturated, and substituted or unsubstituted, the ring structure substitution being selected from one or more R1 groups as defined under (a)-(i) above,
X is selected from the group consisting of C, Si, Ge, Sn and Pb;
R2 is selected from the group consisting of H, unsubstituted C1-C20 hydrocarbyl, C1-C20 hydrocarbyl substituted with at least one Si, and C1-C20 hydrocarbyl substituted with at least one Ge;
m=0 or 1,
Y is selected from the group consisting of hydrocarbyl radicals, hydrosilyl radicals, and hydrogermyl radicals; and
Q1 and Q2 are non-cyclopentadienyl radicals wherein
i) independently, each Q is selected from the group consisting of halide, hydride, unsubstituted C1-C20 hydrocarbyl, C1-C20 hydrocarbyl substituted with at least one R1 group as defined under (a)-(i) above, alkoxide, aryloxide, amide, halide or phosphide; or
ii) together, Q1 and Q2 may form an alkylidene, cyclometallated hydrocarbyl or any other divalent anionic chelating ligand.
Preferred zirconium compounds where two sets of R1 groups are joined together has the following structure:
where the unsubstituted cyclopentadienyl ring is Cp1, and the substituted fluorenyl ring has at least two non-hydrogen radical substituents, wherein each R1 is, independently, a radical selected from:
a) hydrogen radical,
b) hydrocarbyl, silyl or germyl radicals having from 1 to 20 carbon, silicon or germanium atoms,
c) substituted hydrocarbyl, silyl or germyl radicals as defined, wherein one or more hydrogen atoms is replaced by a halogen radical, an amido radical, a phosphido radical, an alkoxy radical, an aryloxy radical or any other radical containing a Lewis acidic or basic functionality,
d) C1-C20 hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from the group consisting of Ge, Sn and Pb,
e) halogen radicals,
f) amido radicals,
g) phosphido radicals,
h) alkoxy radicals, and
i) alkylborido radicals, or
at least two R1 groups are joined together to form, along with the carbon atoms to which they are attached, a C4-C20 ring structure, which is saturated or partially saturated, and substituted or unsubstituted, the ring structure substitution being selected from one or more R1 groups as defined under (a)-(i) above;
X is selected from the group consisting of C, Si, Ge, Sn and Pb;
R2 is selected from the group consisting of H, C1-C20 hydrocarbyl, C1-C20 hydrocarbyl substituted with at least one Si, and C1-C20 hydrocarbyl substituted with at least one Ge;
m=0 or 1,
Y is selected from the group consisting of hydrocarbyl radicals, hydrosilyl radicals, and hydrogermyl radicals; and
Q1 and Q2 are non-cyclopentadienyl radicals wherein
i) independently, each Q is selected from the group consisting of halide, hydride, unsubstituted C1-C20 hydrocarbyl, C1-C20 hydrocarbyl substituted with at least one R1 group as defined under (a)-(i) above, alkoxide, aryloxide, amide, halide or phosphide; or
ii) together, Q1 and Q2 may form an alkylidene, cyclometallated hydrocarbyl or any other divalent anionic chelating ligand.
Such compounds can also include an Lw complexed thereto wherein L is a neutral Lewis base such as diethylether, tetrahydrofuran, dimethylaniline, aniline, trimethylphosphine, n-butylamine, and the like; and xe2x80x9cwxe2x80x9d is a number from 0 to 3.
The term xe2x80x9ccyclopentadienylxe2x80x9d refers to a 5-member ring having delocalized bonding within the ring and typically being bound to M through xcex75-bonds, carbon typically making up the majority of the 5-member positions.
Examples of the bridged, bis(cyclopentadienyl) zirconium compounds of the invention include:
dimethylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dichloride,
dimethylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dimethyl,
dimethylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dibenzyl,
diphenylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dichloride,
diphenylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dimethyl,
diphenylsilanyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dibenzyl,
diphenylmethylene(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dichloride,
methylphenylmethylene(cyclopentadienyl)(trim ethylcyclopentadienyl) zirconium dimethyl,
diphenylmethylene(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dibenzyl,
silacyclobutyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dichloride,
silacyclobutyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dimethyl,
silacyclobutyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dibenzyl,
isopropylidene(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dichloride,
isopropylidene(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dimethyl,
isopropylidene(cyclopentadienyl)(trimethylcyclopentadienyl) zirconium dibenzyl,
dimethylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dichloride,
dimethylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dimethyl,
dimethylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dibenzyl,
diphenylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dichloride,
diphenylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dimethyl,
diphenylsilanyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dibenzyl,
diphenylmethylene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dichloride,
methylphenylmethylene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dimethyl,
diphenylmethylene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dibenzyl,
silacyclobutyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dichloride,
silacyclobutyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dimethyl,
silacyclobutyl(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dibenzyl,
isopropylidene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dichloride,
isopropylidene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dimethyl,
isopropylidene(cyclopentadienyl)(tetramethylcyclopentadienyl) zirconium dibenzyl.
Substituted versions where a hydride, hydrocarbyl, germyl or silyl group replaces one or both chloride ligands of M are suitable in accordance with invention particularly where ionizing anion precursors are activators. Separate or in situ alkylation is typical, e.g., dimethyl replacing dichloride.
A preferred catalyst according to the invention will be those in which Cp2 is tri- or tetra-alkyl substituted with methyl, ethyl, isopropyl or tertiary butyl alkyl groups, or mixed combinations of two or more such alkyl groups. Preferred bridging groups, those particularly suited for increased activity and increased molecular weights, are both silacyclic and aryl-group containing methylene groups, e.g., silacyclobutyl, methylphenylmethylene and diphenylmethylene.
The bridged, bis(cyclopentadienyl) zirconium compounds according to the invention may be activated for olefin polymerization catalysis in any manner sufficient both to remove or complex one Q group such that the metal center becomes sufficiently electron deficient to attract olefinically unsaturated monomers and such that the other Q bond is either itself, or is abstracted and substituted with another Q bond, sufficiently weak so as to permit insertion of it into the olefinically unsaturated monomer to yield a growing polymer, in the manner of traditional coordination/insertion polymerization. The traditional activators of metallocene polymerization art are suitable, those typically include Lewis acids such as aluminum alkyls or alumoxane compounds, and ionizing anion pre-cursors that abstract one Q so as ionize the metal center into a cation and provide a counter-balancing noncoordinating anion.
The term xe2x80x9cnoncoordinating anionxe2x80x9d means an anion which either does not coordinate to said transition metal cation or which is only weakly coordinated to said cation thereby remaining sufficiently labile to be displaced by a neutral Lewis base. xe2x80x9cCompatiblexe2x80x9d noncoordinating anions are those which are not degraded to neutrality when the initially formed complex decomposes. Further, the anion will not transfer an anionic substituent or fragment to the cation so as to cause it to form a neutral four coordinate metallocene compound and a neutral by-product from the anion. Noncoordinating anions useful in accordance with this invention are those which are compatible, stabilize the metallocene cation in the sense of balancing its ionic charge in a+1 state, yet retain sufficient lability to permit displacement by an ethylenically or acetylenically unsaturated monomer during polymerization. Additionally, the anions useful in this invention will be large or bulky in the sense of sufficient molecular size to largely inhibit or prevent neutralization of the metallocene cation by Lewis bases other than the polymerizable monomers that may be present in the polymerization process. Typically the anion will have a molecular size of greater than or equal to about 4 angstroms.
Descriptions of ionic catalysts for coordination polymerization comprised of metallocene cations activated by ionizing anion pre-cursors appear in the early work in EP-A-0 277 003, EP-A-0 277 004, U.S. Pat. Nos. 5,198,401 and 5,278,119, and WO92/00333. These teach a preferred method of preparation wherein metallocene compounds are protonated by an anionic precursors such that an alkyl/hydride group is abstracted from a transition metal to make it both cationic and charge-balanced by the non-coordinating anion. The use of ionizing ionic compounds not containing an active proton but capable of producing the both the active metallocene cation and an noncoordinating anion is also known. See, EP-A-0 426 637, EP-A-0 573 403 and U.S. Pat. No. 5,387,568. Reactive cations other than Bronsted acids capable of ionizing the metallocene compounds include ferrocenium triphenylcarbonium and triethylsilylinium cations. Any metal or metalloid capable of forming a coordination complex which is resistant to degradation by water (or other Bronsted or Lewis Acids) may be used or contained in the anion of the second activator compound. Suitable metals include, but are not limited to, aluminum, gold, platinum and the like. Suitable metalloids include, but are not limited to, boron, phosphorus, silicon and the like. The description of non-coordinating anions and precursors thereto of these documents are incorporated by reference for purposes of U.S. patent practice.
An additional method of making the ionic catalysts uses ionizing anion precursors which are initially neutral Lewis acids but form the cation and anion upon ionizing reaction with the metallocene compounds, for example tris(pentafluorophenyl) boron acts to abstract an alkyl, hydride or silyl ligand to yield a metallocene cation and stabilizing non-coordinating anion, see EP-A-0 427 697 and EP-A-0 520 732. Ionic catalysts for addition polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anionic precursors containing metallic oxidizing groups along with the anion groups, see EP-A-0 495 375. The description of non-coordinating anions and precursors thereto of these documents are similarly incorporated by reference for purposes of U.S. patent practice.
Examples of suitable anion precursors capable of ionic cationization of the metallocene compounds of the invention, and consequent stabilization with a resulting noncoordinating anion include trialkyl-substituted ammonium salts such as are well-known in the art, see U.S. Pat. No. 5,198,401 and WO-A-96/33227, and others above.
Further examples of suitable anion precursors include those comprising a stable carbonium ion, and a compatible non-coordinating anion. These include:
tropillium tetrakispentafluorophenyl borate,
triphenylmethylium tetrakispentafluorophenyl borate,
benzene(diazonium)tetrakispentafluorophenyl borate,
tropillium phenyltris-pentafluorophenyl borate,
triphenylmethylium phenyl-trispentafluorophenyl borate,
benzene(diazonium)phenyltrispentafluorophenyl borate,
tropillium tetrakis(2,3,5,6-tetrafluorophenyl)borate,
triphenylmethylium tetrakis (2,3,5,6-tetrafluorophenyl)borate,
benzene (diazonium)tetrakis(3,4,5-trifluorophenyl)borate,
tropillium tetrakis (3,4,5-trifluorophenyl)borate,
benzene (diazonium)tetrakis(3,4,5-trifluorophenyl)borate,
tropillium tetrakis(3,4,5-trifluorophenyl)aluminate,
triphenylmethylium tetrakis(3,4,5-trifluorophenyl)aluminate,
benzene (diazonium)tetrakis (3,4,5-trifluorophenyl)aluminate,
tropillinum tetrakis(1,2,2-trifluoroethenyl)borate,
triphenylmethylium tetrakis(1,2,2-trifluoroethenyl)borate,
benzene (diazonium) tetrakis(1,2,2-trifluoroethenyl)borate, tropillium tetrakis (2,3,4,5-tetrafluorophenyl)borate,
triphenylmethylium tetrakis(2,3,4,5-tetrafluorophenyl)borate,
benzene (diazonium) tetrakis(2,3,4,5-tetrafluorophenyl)borate,
and, diethylanilinium n-butyltris(pentafluorophenyl)borate.
Where the metal ligands include Q halide moieties, such as in (cyclopentadienyl)dimethylsilyl(tetramethylcyclopentadienyl) zirconium dichloride, which are not capable of discrete ionizing abstraction under standard conditions, these moieties can be converted via known alkylation reactions with organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A-0 500 944, EP-A-1-0 570 982 and EP-A1-0 612 769 for processes describing the reaction of alkyl aluminum compounds with dihalide substituted metallocene compounds prior to or with the addition of activating anion precursor compounds.
Known alkylalumoxanes are additionally suitable as catalyst activators, particularly for the invention metal compounds comprising the halide ligands. The alumoxane component useful as catalyst activator typically is an oligomeric aluminum compound represented by the general formula (Rxe2x80x94Alxe2x80x94O)n, which is a cyclic compound, or R(Rxe2x80x94Alxe2x80x94O)n,AlR2, which is a linear compound. In the general alumoxane formula R is a C1 to C5 alkyl radical, for example, methyl, ethyl, propyl, butyl or pentyl and xe2x80x9cnxe2x80x9d is an integer from 1 to about 50. Most preferably, R is methyl and xe2x80x9cnxe2x80x9d is at least 4. Alumoxanes can be prepared by various procedures known in the art. For example, an aluminum alkyl may be treated with water dissolved in an inert organic solvent, or it may be contacted with a hydrated salt, such as hydrated copper sulfate suspended in an inert organic solvent, to yield an alumoxane. Generally, however prepared, the reaction of an aluminum alkyl with a limited amount of water yields a mixture of the linear and cyclic species of the alumoxane.
When using ionic catalysts comprising bridged Group 4 metal cations and non-coordinating anions, the total catalyst composition will generally additionally comprise one or more scavenging compounds. The term xe2x80x9cscavenging compoundsxe2x80x9d as used in this application and its claims is meant to include those compounds effective for removing polar impurities from the reaction solvent. Such impurities can be inadvertently introduced with any of the polymerization reaction components, particularly with solvent, monomer and catalyst feed, and adversely affect catalyst activity and stability. It can result in decreasing or even elimination of catalytic activity, particularly when a metallocene cation-noncoordinating anion pair is the catalyst composition. The polar impurities, or catalyst poisons include water, oxygen, metal. impurities, etc. Preferably steps are taken before provision of such into the reaction vessel, for example by chemical treatment or careful separation techniques after or during the synthesis or preparation of the various components, but some minor amounts of scavenging compound will still normally be required in the polymerization process itself. Typically the scavenging compounds will be an organometallic compound such as the Group-13 organometallic compounds of U.S. Pat. Nos. 5,153,157, 5,241,025, EP-A-0 426 638 and WO-A-91/09882 and WO-A-94/03506, noted above, and those of WO-A-93/14132 and WO-A-97/22635. Exemplary compounds include triethyl aluminum, triethyl borane, tri-isobutyl aluminum, methyl alumoxane, isobutyl aluminumoxane, and tri-n-octyl aluminum, those having bulky or C6 or higher linear substituents covalently bound to the metal or metalloid center being preferred to minimize adverse interaction with the active catalyst. When an alkyl aluminum or alumoxane is used as activator, any excess over the amount of metallocene present will act as scavenger compounds and additional scavenging compounds may not be necessary. The amount of scavenging agent to be used with metallocene cation-noncoordinating anion pairs is minimized during polymerization reactions to that amount effective to enhance activity. In the process described in this invention, it was found that there is an optimum contact time between the scavenger compound and the reaction mixture to maximize catalyst activity. If the contact time is too long, detrimental catalyst deactivation might occur. All documents are incorporated by reference.
The solution process for the production of the EPC elastomers in accordance with this invention improves process economics and increases product capabilities. For process economics, the combination of high catalyst activity and solvent recovery systems brings significant cost improvements. The improved economics of the high catalyst activity solution process compared with the conventional process is related to savings in the finishing area by not requiring catalyst deashing facilities. In addition, efficient solvent recycling also reduces the environmental impact of the process with respect to volatile organic compound emissions to meet increasingly more restrictive regulatory levels. Additionally, the use of the invention process allows for high diolefin conversion from monomer to incorporated mer unit in the polymer, thus reducing cost of separation and recycle. Typical conversion ratios of diolefin monomer can range from 20%, 30% or up to as high as 40%, and higher.
The polymerization process of the invention involves contacting the polymerizable monomers (ethylene, xcex1-olefin and, diene monomer) in solution with the described ionic catalyst composition, preferably at high reaction temperatures, from about 20xc2x0 C. to 180xc2x0 C., and can be suitably conducted in the following manner. The solvent is heated to reaction temperature prior to introduction into the reaction vessel. The solvent is then provided to the reaction vessel after polymerizable monomer is introduced in either liquid, gas or solution form into that reaction solvent. A reaction medium is formed comprising the solvent within which the catalyst composition and monomers are contacted for the polymerization reaction. Typically, the scavenging compound is introduced into the reaction solvent to reduce or eliminate catalyst poisons present in any of the reaction medium components prior to introduction into the reactor. If the scavenging compound and activator are different, and contacted with each other for sufficient time, adverse effects on the effectiveness of that activator might occur. In this process, the activator and metallocene compound are contacted in the polymerization reaction vessel in the presence of the polymerizable monomers, comprising the in-situ activation.
A suitable solution reaction can be conducted at pressures from atmospheric to 500 psig (1-35 bar), preferably from 100 to 300 psig (8 to 21 bar). Preferred reaction temperatures are above 30xc2x0 C., preferably up to and above about 80xc2x0 C. Typically the polymerization reaction will be exothermic and the reactor or reactor feeds will be chilled or cooled in accordance with known methods to assure that temperatures do not exceed those reasonably suitable for the polymer being produced. Another preferred process in which any of the catalyst, cocatalyst and scavenger selections disclosed in this application can be advantageously practiced is that of a continuous, solution process operated at or above 90xc2x0 C. to 200xc2x0 C., preferably above 110xc2x0 C. Typically this process is conducted in an inert hydrocarbon solvent, linear, cyclic or branched aliphatic, or aromatic, at a pressure of from 20 to 200 bar, the reactants being added directly into a suitable reaction vessel containing the solvent at preferred operating temperatures.
An additionally suitable homogeneous process of polymerization is that conducted at high pressure, that is at from 200 to 3000 bar, preferably from 500 to 2500 bar in a homogeneous single phase or two fluid phases, with or without unreactive diluents or solvents at temperatures generally above the melting point of the polymer being produced. Such processes are typically known and may include the use of scavenger compounds and catalyst deactivation or killing steps, see for example U.S. Pat. No. 5,408,017, WO 95/07941, WO 92/14766, and WO 97/22635. Each of these documents and their U.S. counterparts are incorporated by reference for purposes of U.S. patent practice. Preferred catalyst deactivators, or killers, include high molecular weight, non-recyclable compounds, such as poly vinyl alcohol which exhibit the functional capacity to complex with the catalysts so as to deactivate them while not forming volatile polar by-products or residual unreacted compounds.
The feedstock purification prior to introduction into the reaction solvent follows standard practices in the art, e.g. molecular sieves, alumina beds and oxygen removal catalysts are used for the purification of ethylene, xcex1-olefin, and optional diene. The solvent itself as well, e.g., hexane and toluene, are similarly treated. Purification of the dienes was observed to increase diene conversion, best results were obtained when the diene was fractionally distilled with CaH2 as the purification method.
The xcex1-olefin monomer(s) and diene monomer(s) are introduced in an amount proportional to the levels of incorporation desired for the polymer to be produced and the effective reactive ratios for the polymerizable monomers in the presence of the specific catalyst chosen. In the preferred embodiment the combination of the xcex1-olefin monomer(s) in reaction solvent as introduced into the reactor and effective vapor pressure of xcex1-olefin monomer(s) is maintained according to the rate of incorporation into the copolymer product. In an alternative embodiment, the partial pressure in the reactor will be provided by ethylene alone in which situation the xcex1-olefin monomer(s) are added solely with reaction solvent. The amounts and vapor pressure will vary according to catalyst selection and polymer to be produced, but can be empirically determined well within the skill in the art, particularly in view of the description provided in the following examples.
The catalyst activator, e.g., non-coordinating anion precursor, ionizing anionic precursor, or alumoxane, can be introduced along with or separately from introduction of the optional diolefin monomer(s), if used. The diolefin can be provided in an amount effective for its rate of reaction and rate of conversion. The catalyst activator can be provided in an amount that is equal to 0.2 to 10 molar equivalents of the Group 4 metallocene compound, preferably 0.25 to 5, and even more preferably 0.33 to 3.0, when a noncoordinating anion precursor. Typically the provision of the noncoordinating anion precursor activator will be in an effective solvent, typically an aromatic solvent such as toluene. Monitoring of polymerization activity by known methods will permit on-line adjustment of alumoxane to assure neither excess nor deficit amounts are maintained for unwanted periods.
The scavenging compounds are provided separately afterwards or with one of the foregoing feedstreams, in an amount suitable to increase the activity of the catalyst but in an amount lower than that at which depression of reactivity is observed. Typically an effective amount of the scavenging compound is about 0 (e.g., with an alumoxane activator) to 100 mol. ratio based upon the ratio of scavenging compound to activator, preferably the ratio is 0.3 to 30, and most preferably it is 0.5 to 10.
Ethylene gas is then provided into the reaction vessel in an amount proportional to, the level of incorporation desired and the effective reactive ratios for the polymerizable monomers in the presence of the specific catalyst chosen, as with the xcex1-olefin monomer(s). The polymerization starts upon contact of the monomers with the activated catalyst and the rates of supply of each of the components of the composition are adjusted for stable operations at the level of production, molecular weight, monomer incorporation and equipment limitations. The reaction temperature may be permitted to exceed the initial temperature but will preferably be at all times greater than the lower limit of the ranges described above for the invention process.
The solvents for the polymerization reaction will comprise those known for solution polymerization, typically the aliphatic solvents represented by hexane, or the aromatic solvents, represented by toluene. Additional examples include heptane, cyclohexane, and Isopar E (C8 to C12 aliphatic solvent, Exxon Chemical Co., U.S.). Preferably the solvent is aliphatic, most preferably it is hexane.
Though not strictly necessary for the solution polymerization process as described, the catalyst according to the invention may be supported for use in alternative gas phase, bulk, or slurry polymerization processes where the high activity benefits of the catalysts are sought to be applied. Numerous methods of support are known in the art for copolymerization processes for olefins, particularly for catalysts activated by alumoxanes, any is suitable for the invention process in its broadest scope. See, for example, U.S. Pat. No. 5,227,440. An example of supported ionic catalysts appears in WO 94/03056. When using a Lewis acid ionizing catalyst activator a particularly effective method is that described in U.S. Pat. No. 5,643,847. A bulk, or slurry, process utilizing supported, biscyclopentadienyl Group 4 metallocenes activated with alumoxane co-catalysts is described as suitable for EPM and EPDM in U.S. Pat. Nos. 5,001,205 and 5,229,478, these processes will additionally be suitable with the catalyst compositions of this application. Each of the foregoing documents is incorporated by reference for purposes of U.S. patent practice.
Though the Examples and the discussion are directed to a single reactor configuration and narrow polydispersity polymers, it is well-known that the use in series of two such reactors each operated so as to achieve different polymer molecular weight characteristics, or by blending polymers from different reactor conditions or utilizing two or more different transition metal catalysts in one or more reactors, can yield improved processing polymers. The disclosures of U.S. Pat. No. 4,722,971 and WO 93/21270 are instructive and are incorporated for purposes of U.S. patent practice. Though directed to the use of vanadium catalysts, the substitution of the catalyst compositions of this invention into one such reactor, or two different invention catalysts into two such reactors, or similar use in two separate polymerizations with subsequent physical blending of the polymer products, will permit tailoring of characteristics (e.g., molecular weights and diene contents) suitable for balancing vulcanization properties with processability. Similarly, the use of mixed catalyst compositions, the invention catalysts with themselves or with others, in one or more such reactors will permit preparation of bimodal or multimodal EPC polymers having improved processing properties.
The following examples are presented to illustrate the foregoing discussion. All parts, proportions and percentages are by weight unless otherwise indicated. Although the examples may be directed to certain embodiments of the present invention, they are not to be viewed as limiting the invention in any specific respect. Methods of determining Mn and monomer contents by NMR and GPC for the illustrative EPDM examples of the invention are described in U.S. Pat. No. 5,229,478 which is incorporated by reference for purposes of U.S. patent practice. For measurement of comonomer contents in the EPC elastomers, the method of ASTM D3900 for ethylene-propylene copolymers between 35 and 85 wt. % ethylene was used. Outside that range the NMR method was used. See also, U.S. Pat. No. 4,786,697 which is incorporated by reference for purposes of U.S. patent practice.


Injector for inserting objects such as transponders (4) into a living being. The injector is provided with positioning means for fixing the position of the insertion needle (9) relative to the living being. These positioning means comprise a pin (5) designed to rest with the shank thereof against a part of the living being, such as the head (1) . The position of the insertion needle (9) can thereby be determined irrespective of differences occurring from one animal to another.

Such an injector is known from existing prior art. The other end of the pin-shaped member is in this case connected to a fitting. The shape of this fitting corresponds to the part of the body into which the pin has to be inserted, for example the part of the head of a pig behind the ear. Such a fitting is slightly curved.
It is important to place objects which are inserted with such injectors, such as transponders, in an accurately defined position. Preference is given to placing the transponders at an accurately defined distance and position behind the skin. Since the heads of, for example, pigs have a different curvature depending on the age and breed, it is necessary in the case of the device according to existing prior art injectors to use different fittings, otherwise it cannot be ensured that the transponder is positioned accurately in the desired place. Besides, it is possible with the fitting according to the existing prior art injectors to make a slight shift over the head part in question, so that the needle is inserted in slightly different positions relative to the adjacent skin, something which is undesirable. Costs and other inconveniences are also involved in the production and storage of different shapes of fittings.


A sweep frequency vibrator is set forth. It has an elongate cylindrical housing closed at the top and bottom ends. On the interior, there is a reactionary mass fixed to identical upper and lower piston ends. They are received in seal isolated chambers, one being formed in a moveable plug. The plug is moved to thereby vary the spacing of the chambers. As the frequency is changed, plug is moved to assure sufficient clearance from the excursion of the reactionary mass. Hydraulic oil under pressure is delivered to control valves, one for each piston end. The two control valves and piston ends have very short flow lines. Moreover the excursion permitted for the plug assures operation without bottoming out.

A vibrator is a device which is used to form vibrations transmitted into the earth in seismic investigations. A vibrator is a device that is typically installed at the earth's surface to form a vibration which is directed into the earth and reflected by various geological horizons in the earth to thereby provide data indicative of the nature of the seismic formations. The propagation of the vibrations into the earth involves a propagation of a generally spherical wavefront. Thus, the intensity of the energy on a per unit area basis decreases with the square of the distance of the propagation. Since the signal must be propagated into the earth, reflected at a far horizon and return to the surface, the reflected signal is also subject to a square law decrease, the propagation of the signal involves a decrease in intensity which is a function of the fourth power of the distance. This can be reduced significantly by installing a vibrator in a well borehole. Such a vibrator has to be an elongate cylindrical structure to fit in the well borehole. Devices of this sort typically are hydraulically powered. A vibrator therefore is required which converts hydraulic power into vibrations for surface and down hole uses.
The present disclosure is directed to such a system which enables the extension of the frequency range of the device. Using a typical low frequency of 10 hertz as an example, it is desirable that the frequency increase up to some significantly greater level for operation. The response of the seismic formations is different, and therefore a change in frequency provides added information with regard to the formations. The present disclosure is directed to control valves which are connected to provide hydraulic power to both sides of a piston which is in a cylinder to enable the piston to be driven in a double acting mode. The cylinder and piston construction reciprocates a reactionary mass.
Consider as an example a device which operates at 10 hertz. If it is desirable to operate the same vibrator at 600 hertz and output the same force, the system must change the stroke by an amount which is very substantial. An example will be developed below where the stroke at 10 hertz is 1.9 inches while the stroke is reduced at 600 hertz to 0.0005 inches. Focusing for the moment on the power requirements for that, the performance of the hydraulic fluid becomes a significant limiting factor. In other words, the hydraulic oil which is normally assumed to be an incompressible liquid at most circumstances limits the performance. The fact that it is somewhat compressible is dependent primarily on the bulk modulus of the hydraulic oil and the volume of the hydraulic oil that is in the cylinder. The first factor can be enhanced by selection of hydraulic fluids which have the optimum bulk modulus. The last factor more aptly involves the design of the flow lines and the filled region of the cylinder. In other words, the frequency response of the system can be increased if the volume inside the moveable parts is reduced. One way to reduce this is to decrease the volume inside the flow lines. Another way to reduce this volume is to reduce the flow regions of the valves which connect the system. In other words, the volume inside the cylinder is reduced. As will be described in some detail, the present disclosure omits a four-way valve and uses instead two separate three-way valves. The three-way valves are located at opposite ends of the cylinder. Moreover, the three-way valves are immediately adjacent to the ends of the pistons in the cylinder for suitable switching. Furthermore, for operation at high frequency, the cylinder length can be shortened so that the cylinder chambers are reduced thereby accommodating extending performance at higher frequencies. This enables a system whereby the reciprocating mass is located near the center of the chamber within the cylinder. This enables the extended frequency performance mentioned. The present disclosure further sets forth a mechanism whereby the head area can be extended. Through this technique, there is an enhanced head region so that low frequencies can be generated by involving the added head region. It it not involved for operation at high frequencies. In other words, this reduces the volume of the head area so that hydraulic fluid requirements are reduced at high frequencies.
The present apparatus is a wide frequency range, sweep frequency vibrator of elongate cylindrical construction which especially finds use in downhole seismic generators. It is a system which is hydraulically powered where the hydraulic fluid is delivered through two separated three-way valves. They are located at opposite ends of the structure. Primarily, the structure involves an elongate cylindrical chamber or housing which is closed at the ends. There is a vibrating mass which is driven in a double acting mode. As will be detailed, it is driven at different frequencies depending on the switching of the hydraulic fluid which is delivered through the valves. Examples of operation will be given.


This invention discloses a novel rewritable phase-change recording medium for optical data storage, which is based on the GaSbTe ternary alloy system. The designed compositions reside on the Sb7Te3—GaSb and Sb2Te3—GaSb pseudo-binary tielines, and the claimed region can be expressed by the formula (SbxTe100-x)1-z(GaySb100-y)z, 35≦x≦80, 40≦y≦50, 0.05≦z≦0.9. The crystallized phase of the GaSbTe films is a single phase after laser annealing, and the crystal structure is hexagonal with continuous variation in lattice constants. The lattice parameters, a is from 4.255 Å to 4.313 Å and c is from 11.200 Å to 11.657 Å, corresponding to the c/a ratio 2.60 to 2.73. The crystallization kinetics shows increased crystallization temperature (181 to 327° C.) and activation energy (2.8 to 6.5 eV) with increasing GaSb content. The Sb7Te3-rich compositions in the GaSbTe recording media are characteristic of enhanced recrystallization, while those with increasing GaSb content are indicative of higher rate of crystal growth and better erasability. The compositions around Ga2Sb5Te3 exhibit the features of nearly complete erasure and stable cycling performance.

An erasable phase-change optical disk utilizes a phase change between the crystalline and amorphous states of a recording layer to accomplish the functions of writing and erasing. The working principles of the erasable phase-change optical disk will be introduced in conjunction with typical prior art references hereinafter for a better understanding of the present invention.
A typical erasable phase-change optical disk is shown in FIG. 1, which comprises a phase-change recording layer 2 interposed between an upper dielectric layer and a lower dielectric layer 3 on a substrate 1, a reflective layer 4 on the upper dielectric layer, and a plastic protection layer 5 on the reflective layer 4. A suitable material for making the dielectric layers 3 is SiO2—ZnS. The substrate 1 may be formed of polymethyl methacrylate, polycarbonate or a glass. Suitable materials for forming the reflective layer 4 include Au, Cu, Al, Ni, Cr, Pt, Pd and an alloy thereof.
The currently used erasable phase-change optical disks utilize a chalcogenide material based on Te or Se as the recording layer. When a region of the recording layer is subjected to a rapid heating to a molten state upon irradiation of a focused laser beam with a high power short pulse modulation, the region will be conductively quenched by the adjacent layers (e.g. the dielectric layers and reflective layer) to an amorphous state, so that a recording mark is formed. The amorphous recording mark has a reflectance lower than that of the blank crystalline region (for some special alloys the reflectance of amorphous recording mark is higher), and the difference in reflectance is used for reproduction of signals. A medium power and long pulse laser beam is used to erase the recording mark, which resumes the blank crystalline region by heating to a temperature between its melting point and crystallization point.
The chalcogenide material was first used as the phase-change recording layer by S. R. Ovsinsky, et al. in U.S. Pat. No. 3,530,441, wherein thin films of Te.sub.85 Ge.sub.15 and Te.sub.81 Ge.sub.15 S.sub.2 Sb.sub.2 produce a reversible phase-transition according to irradiation with high energy density light such as the laser beam. Thereafter, most of the research works have concentrated on the chalcogenide materials, for examples GeTe, InSe, InSeTI, InSeTICo, GeSbTe, GeTeSn, GeTeAs, GeTeSnAu, InTe, InSeTe, InSbTe, and SbSeTe, etc. all pertain to the chalcogenide material. Among them, the series of GeSbTe alloys developed by Matsushita Electric Industrial Co., Ltd., Japan, in U.S. Pat. Nos. 5,233,599; 5,278,011; and 5,294,523 are the most promising ones. The details of these patents are hereby incorporated by reference in their entirety.
In the GeTe—Sb2Te3 pseudo-binary alloy system, three intermetallic compounds exist in between the GeTe and Sb2Te3 terminal compounds. They are, in sequence, Ge2Sb2Te5, GeSb2Te4 and GeSb4Te7. Yamada et al. of Matsushita heavily studied these pseudo-binary alloys, and disclosed their results in the Journal of Applied Physics 69(5), pp. 2849 (1991). They found that the laser-induced crystallization time for the amorphous film can be smaller than 100 ns that decrease with increasing Sb2Te3. When the composition deviate the pseudo-binary line, the crystallization time rapidly increases. Crystallization temperature, around 200° C. lowers with increasing Sb2Te3. A metastable FCC structure forms at the onset of crystallization, it then converts to a stable HCP structure.
With decreasing spot size of the laser while constant increase of recording density, new recording media with faster and faster crystallization speed is drastically needed to improve data transfer rate. Scientists in Philip found that the compositions at around Sb70Te30 in the same GeSbTe system are characteristic of superior crystallization capability (see the Japanese Journal of Applied Physics 40, p. 1592 (2001)). These compositions show low nucleation rate while high growth rate, hence were called growth driven or fast growth type of optical recording media. Traditional GeSbTe compositions, such as Ge2Sb2Te5, belong to nucleation driven type of optical media, and is characteristic of large amount of nuclei formation together with grain growth. The crystallization speed depends on the time required for nucleation and growth. While for growth driven type of media, crystallization proceeds with the enlargement of existing nuclei at the peripheral of amorphous recording spots. Time for crystallization depends on only the time for grain growth that favors the ever smaller recording bits.
The growth driven materials in use are, among others, AgInSbTe of Ricoh, InGeSbTe of Phlip, those are compositions near Sb70Te30, with a modification using Ag, In, and/or Ge to tailor the crystallization behavior. The present invention proposes a new alloy system based on GaSbTe ternary alloys possessing high growth driven crystallization speed and is suitable for the media of high recording density using blue lasers.

Phase-change recording media based on the Ga-Sb-Te system for ultra-high density optical recording


A door system includes a window and a door frame. The door frame includes a first panel and a second panel. The first panel includes a first outer portion and a second outer portion. The first outer portion has a first outer leg, an intermediate portion, and a second outer leg that together define a cavity. The second panel has a first inner portion, a lip portion and a second inner portion. The first inner portion is joined to the second outer portion of the first panel. The second inner portion has a first inner leg and a second inner leg that together define a seal channel wall extending within the cavity. The lip portion includes an offset portion extending in a direction opposite to that of the seal channel wall.

Doors are typically subject to loads arising from latching and unlatching against a frame. For example, doors employed on machines are often opened and closed relative to a frame of the machine, during which, the door may undergo a twisting moment each time a latch present on the door is latched to or unlatched from the frame of the machine. Many previously known configurations of door panels have been known to undergo such twisting moment with latching of the door to the frame.
Manufacturers of door assemblies have been constantly directing efforts to improve the overall strength of doors so as to allow the doors to withstand twisting moments and/or other types of operational loads encountered during latching of the door. For reference, U.S. Pat. No. 8,556,329 discloses a door panel that has a double-panel structure and that is capable of ensuring sufficient strength at portions where hinges are attached.