The invention concerns a monomode optical fiber having at a wavelength of 1550 nm a dispersion slope from xe2x88x920.8 ps/nm2.km to xe2x88x920.5 ps/nm2.km and a chromatic dispersion from xe2x88x92130 ps/nm.km to xe2x88x9290 ps/nm.km, the fiber having a cladding and a core whose index profile features a central part having an index higher than that of the cladding, a ring having an index higher than that of the cladding and lower than that of the central part, and a trench between the central part and the ring having an index lower than that of the cladding, and the use of a fiber of this kind to compensate dispersion. The fiber of the invention finds applications in high bit rate transmission systems in particular. The invention also concerns a wavelength division multiplex optical fiber transmission system comprising at least one section of fiber in accordance with the invention.

The present invention relates to monomode optical fibers which can be used in particular to compensate dispersion, and it also relates to optical fiber transmission and more particularly wavelength division multiplex transmission using dispersion shifted fiber as line fiber.
The refractive index profile of optical fibers is generally characterized as a function of the curve representing variations in the refractive index as a function of the radius of the fiber. It is conventional to plot on the abscissa axis the distance r to the center of the fiber and on the ordinate axis the refractive index defined in terms of its absolute or percentage difference from the index of the cladding of the fiber. The expressions xe2x80x9cstep profilexe2x80x9d, xe2x80x9ctrapezium profilexe2x80x9d and xe2x80x9ctriangle profilexe2x80x9d are used to refer to curves representative of the index variation as a function of the radius which respectively have step, trapezium and triangle shapes. These curves are generally representative of the theoretical profile or set point profile of the fiber and fiber fabrication constraints can yield a substantially different profile.
It is advantageous to manage chromatic dispersion in new high bit rate wavelength division multiplex (WDM) transmission networks, in particular for bit rates of 10 Gbit/s and above; the objective is to obtain substantially zero cumulative chromatic dispersion over the link for all wavelength values of the multiplex or comb, in order to limit widening of the pulses. A cumulative value of a few hundred ps/nm for the dispersion is acceptable. Increasing the unit bit rate of each channel makes it even more necessary to compensate cumulative chromatic dispersion.
Dispersion shifted fibers (DSF) are now commercially available. In these fibers the chromatic dispersion of the transmitted wave is substantially zero at the transmission wavelength at which they are used, which is generally different from the wavelength of 1.3 xcexcm at which the dispersion of the silica is substantially zero; silica is compensatedxe2x80x94hence the use of the term xe2x80x9cshiftedxe2x80x9dxe2x80x94by an increase in the index difference xcex94n between the fiber core and the optical cladding. This index difference shifts the wavelength of zero chromatic dispersion; it is obtained by introducing dopants into the preform during its fabrication, for example by an MCVD process well known in the art and not described in detail here. A typical value for the index difference between the cladding and the core of the fiber is 15xc3x9710xe2x88x923; the index of the silica can be increased by doping with geranium, for example. Non-zero dispersion shifted fibers (NZ-DSF) are dispersion shifted fibers which have non-zero chromatic dispersion outside the range of wavelengths used for transmission, typically outside the range of wavelengths from 1520 nm to 1580 nm.
It has been proposed to use dispersion compensating fiber (DCF) to correct the chromatic dispersion induced by a stepped index line fiber. For example, European Patent Application EP-A1-0 554 714 describes dispersion compensating fiber for standard line fibers having a stepped index profile and zero chromatic dispersion at around 1310 nm or flat dispersion fibers having two chromatic dispersion zeros between 1300 nm and 1600 nm. A fiber of this kind has a total dispersion less than xe2x88x9220 ps/nm-km at a given wavelength in the range from 1520 nm to 1565 nm and an attenuation of less than 1 dB/km. For example, the general shape of the profile of fiber of this kind has a narrow central part whose index is higher than that of the cladding, a ring with a higher index than the cladding and a lower index than the central part, and two trenches with the same index, one between said central part and the ring and one between the ring and the cladding. The second trench is optional.
However, when using these DCFs no allowance is made for chromatic dispersion or for the chromatic dispersion slope over the whole of the range of wavelengths concerned. Thus if it is required to compensate only chromatic dispersion, for example, without compensating the slope of said chromatic dispersion, drift occurs in the compensation and the system is not completely compensated at the output since the chromatic dispersion slope is insufficiently compensated. Steps must be taken at the output so that at this end all the wavelengths have the same chromatic dispersion, since otherwise it is necessary to compensate length by length, which quickly becomes prohibitive from both the technical and cost points of view. Accordingly, in this case, it is then necessary to use a greater length of DCF, which induces greater chromatic dispersion and leads to a higher cost.
The fiber of the invention aims to solve this problem of the prior art by enabling correct compensation not only of the cumulative dispersion in the line fiber but also of the dispersion slope. It assures good wavelength division multiplex transmission without inducing high levels of attenuation and it limits non-linear effects. The invention applies in particular to transmission systems using NZ-DSF fibers with RZ, NRZ or soliton pulses.
To be more precise, the invention proposes a monomode optical fiber having at a wavelength of 1550 nm a dispersion slope from xe2x88x920.8 ps/nm2.km to xe2x88x920.5 ps/nm2.km and a chromatic dispersion from xe2x88x92130 ps/nm.km to xe2x88x9290 ps/nm.km, the fiber having a cladding and a core whose index profile features a central part having an index higher than that of the cladding, a ring having an index higher than that of the cladding and lower than that of the central part, and a trench between the central part and the ring having an index lower than that of the cladding.
The line fiber advantageously has no zero value of chromatic dispersion in the range of wavelengths of the multiplex.
Another advantage of the fiber of the invention is that when it is used to compensate the chromatic dispersion of a line fiber the ratio between the chromatic dispersion and the chromatic dispersion slope can be of the same order of magnitude as the same ratio for the line fiber.
In particular, the fiber of the invention generally enables the use of dispersion compensating fiber less than one-tenth the length of the line fiber and preferably less than one-twentieth said length.
The fiber of the invention preferably has a chromatic dispersion slope from xe2x88x920.7 ps/nm2.km to xe2x88x920.6 ps/nm2.km at a wavelength of 1550 nm.
The dispersion compensating fiber advantageously has a chromatic dispersion close to xe2x88x92100 ps/nm.km at a wavelength of 1550 nm.
The difference (xcex94n1) between the index of the central part of the core and the index of the cladding can be from 20xc3x9710xe2x88x923 to 30xc3x9710xe2x88x923 and is preferably around 25xc3x9710xe2x88x923.
The central part of the core advantageously extends out to a radius (r1) from 1.15 xcexcm to 1.25 xcexcm and preferably around 1.2 xcexcm.
The difference (xcex94n3) between the index of the ring of the core and the index of the cladding can be from 0.5xc3x9710xe2x88x923 to 1.5xc3x9710xe2x88x923 and is preferably around 1xc3x9710xe2x88x923.
The ring advantageously has a thickness (r3xe2x88x92r2) from 3.5 times to 4.5 times the radius (r1) of the central part and preferably around four times that radius.
The difference (xcex94n2) between the index of the trench between the central part and the ring and the index of the cladding can be from xe2x88x924.5xc3x9710xe2x88x923 to xe2x88x925.5xc3x9710xe2x88x923 and is preferably around xe2x88x925xc3x9710xe2x88x923.
The trench between the central part and the ring advantageously has a thickness (r2xe2x88x92r1) from 2.5 times to 3.5 times the radius (r1) of the central part and preferably around 3 times that radius.
In one preferred embodiment of the invention the index profile preferably has a trench with an index less than that of the cladding between the ring and the cladding.
The difference (xcex94n4) between the index of the trench between the ring and the cladding and the index of the cladding can be from xe2x88x920.1xc3x9710xe2x88x923 to xe2x88x920.5xc3x9710xe2x88x923 and is preferably around xe2x88x920.3xc3x9710xe2x88x923.
The trench between the ring and the cladding advantageously has a thickness (r4xe2x88x92r3) from 0.8 times to 1.2 times the radius (r1) of the central part and preferably approximately equal to that radius.
The invention also concerns the use of a monomode optical fiber of the invention to compensate dispersion.
Finally, the invention concerns a wavelength division multiplex optical fiber transmission system comprising at least one monomode dispersion shifted line fiber section and at least one monomode dispersion compensating fiber section in accordance with the invention.
In one embodiment of the invention, the line fiber has a chromatic dispersion at 1550 nm from 2 ps/nm.km to 6 ps/nm.km and preferably around 4 ps/nm.km.
In another embodiment of the invention, the line fiber has a chromatic dispersion slope at 1550 nm from 0.06 ps/nm2.km to 0.08 ps/nm2.km and preferably in the order of 0.075 ps/nm2.km.

Dispersion compensating fiber for wavelength division multiplexed optical fiber transmission systems using dispersion shifted fiber as line fiber


Apparatuses including a first-in first-out circuit are described. An example apparatus includes: a first-in first-out circuit including a first latch, a second latch and a logic circuit coupled in series. The first latch receives first data and latches the first data responsive to a first input pointer signal. The second latch receives the latched first data from the first latch and latches the received first data responsive to a second input pointer signal that has a different phase from the first input pointer signal and thus provides a second data. The logic circuit receives the second data and an output pointer signal and further provides an output data responsive to the output pointer signal.

High data reliability, high speed of memory access, lower power consumption and reduced chip size are features that are demanded from semiconductor memory. In recent years, three-dimensional (3D) memory devices have been introduced. Some 3D memory devices are formed by stacking chips (e.g., dies) vertically and interconnecting the chips using through substrate vias (TSVs). Benefits of the 3D memory devices include shorter interconnects which reduce circuit delays and power consumption, a large number of vertical vias between layers which allow wide bandwidth buses between functional blocks in different layers, and a considerably smaller footprint. Thus, the 3D memory devices contribute to higher memory access speed, lower power consumption and chip size reduction. Example 3D memory devices include Hybrid Memory Cube (HMC), High Bandwidth Memory (HBM), and a wide-I/O dynamic random access memory (DRAM).
For example, High Bandwidth Memory (HBM) is a type of memory including a high-performance DRAM interface chip and vertically stacked DRAM chips. A typical HBM stack of four DRAM chips (e.g., core chips) has two 128-bit channels per chip for a total of eight input/output channels and a width of 1024 bits in total. An interface (IF) chip of the HBM provides an interface with the eight input/output channels, which function independently of each other. In the HBM, data transmission between chips (e.g., between an interface chip and core chips) via through substrate vias (TSVs) may cause high power consumption, due to current charge and discharge at the TSVs as capacitors.
Throughout a semiconductor device, in order to temporary store data while maintaining an order of a data, a first-in-first-out (FIFO) circuit is used. 3D memory devices (e.g., HBM and the like) support data bus inversion ("DBI") during write and read operation for reducing currents in data transmission between a host controller and chips (e.g., dies) via a data bus. One of DBI algorithms, DBI-AC algorithm, is used to limit the number of simultaneously transitioning data bits (e.g., a half of bits or fewer) across the width of the interface. Under the DBI-AC algorithm, all the bits of current data to be transmitted are inverted in logic level prior to transmission of the current data, if a majority of bits of the current data are different in logic level from previous data (e.g., immediately preceding data) transmitted one data transmission cycle before the current data without inversion. If the previous data was transmitted with inversion, however, the current data is transmitted as is, even if the majority of bits of the current data are different in logic level from the previous data. DBI calculation is performed to detect whether the majority bits of the current data are different in logic level from the previous data. Based on the majority bits' transitions based on the DBI calculation result and previous execution status of the DBI operation, a DBI bit indicating whether the DBI is executed on the current data. Since the DBI calculation involves data comparison of the current data with the previous data, FIFO circuits are included in the 3D memory devices.
FIG. 1A is a circuit diagram of a First-In-First-Out (FIFO) circuit 10 including a plurality of flip-flop (FF) circuits 11a to 11d according to the prior art. FIG. 1B is a circuit diagram of an FF circuit 110 according to the prior art. For example, the FF circuit 110 may be each FF circuit of the plurality of FF circuits 11a to 11d. For example, The FF circuit 110 may include three inverters 111-113 and four clocked inverters 114-117. The plurality of FF circuits 11a to 11d are coupled in series, as shown in FIG. 1A. FIG. 1C is a timing diagram of signals in the FIFO circuit according to the prior art. The signals include an input signal at a data input node Din, a clock signal CLK, FF output signals ff0, ff1, ff2 from the FF circuits 11a, 11b, 11c, and an output signal at a data output node Dout. The plurality of FF circuits 11a to 11d conveys data received serially from the data input node Din of the FIFO circuit 10 that is coupled to a data input node D of the FF circuit 11a to the data output node Dout of the FIFO circuit 10 that is coupled to a data output node Q of the FF circuit 11d, by periodically alternating a signal level of the clock signal CLK provided to the plurality of FF circuits 11a to 11d, while maintaining a transmission order of the data. By increasing a number of FF circuits of the plurality of FF circuits, more data can be stored in the FIFO circuit 10. However, increasing the number of the FF circuits also increases power consumption to convey a clock signal CLK to run the FF circuits as well as a layout area of the FIFO circuit 10.
Alternatively, a plurality of latch circuits have been used in a First-In-First-Out (FIFO) circuit. FIG. 2A is a circuit diagram of a First-In-First-Out (FIFO) circuit 20 including a plurality of latch circuits 21a to 21d according to the prior art. In the FIFO circuit 20, the plurality of latch circuits 21a to 21d are coupled in parallel between a data input node Din of the FIFO circuit 20 and a data output node Dout of the FIFO circuit 20 in order to suppress a layout area and power consumption. The FIFO circuit 20 also includes a plurality of NAND circuits 22a to 22d coupled to output nodes of the latch circuits 21a to 21d, respectively. The FIFO circuit 20 further includes a NAND circuit 23 that receives output signals from the plurality of NAND circuits 22a to 22d and provides an output signal to the data output node Dout after executing a logic NAND operation. FIG. 2B is a circuit diagram of a latch circuit 210 according to the prior art. The latch circuit 210 is used as each of the latch circuits 21a, 21b, 21c and 21d. The latch circuit 210 includes two inverter circuits 215 and 216 and two clocked inverters 217 and 218.
In order to operate the latch circuits 21a, 21b, 21c and 21d in the FIFO circuit 20, pointer signals are provided. FIG. 2C is a circuit diagram of a pointer circuit 220 according to the prior art. The pointer circuit 220 provides input pointer signals ip0, ip1, ip2 and ip3 and output pointer signals op0, op1, op2 and op3. The pointer circuit 220 includes a plurality of flip-flop (FF) circuits 221-224, a plurality of NAND circuits 226-229 and a plurality of buffers 230-233, as shown in FIG. 2C. The plurality of flip-flop (FF) circuits 221-224 provide output signals p0-p1 to the plurality of NAND circuits 226-229 and the plurality of buffers 230-233, respectively. The plurality of NAND circuits 226-229 provide the ip0-ip3 signals that each has a pulse width of a half clock cycle responsive to the clock signal CLK. The plurality of buffers 230-233 provide the op0-op3 signals that each has a pulse width of one clock cycle responsive to the clock signal CLK. The latch circuits 21a to 21d operate latching functions (e.g., storing input signals and providing the input signals responsive to timing signals) of an input signal from the data input node Din and provide lat0 to lat3 signals, respectively. Because the plurality of NAND circuits 22a, 22b, 22c and 22d receive lat0 to lat3 signals and the op3, op0, op1, op2 signals respectively, the plurality of NAND circuits 22a, 22b, 22c and 22d operate logic NAND operations between the lat0, lat1, lat2 and lat3 signals and the op3, op0, op1, op2 signals that have an active pulse three clock cycles after an (negative) active pulse of the ip0, ip1, ip2, ip3 respectively, and the NAND circuits 22a, 22b, 22c and 22d may provide output signals with a delay of three clock cycles with respect the lat0 to lat3 signals. In the FIFO circuit 220 of FIG. 2C, the ip0 to ip3 signals and the op0 to op3 signals are generated from the identical clock signal CLK; however, the ip0 to ip3 signals and the op0 to op3 signals can be generated by using two separate clock signals.
When a data width (i.e. a number of data bits) is small, including a pointer circuit is not effective and advantageous. On the other hand, including a pointer circuit in a FIFO circuit with a great data width (i.e., a number of data bits) is advantageous because reduction of FIFO circuit layout area and power consumption overweighs an additional area occupied by the pointer circuit. Increasing the number of data to be stored can be achieved by increasing the number of latch circuits to be coupled in parallel to one another in the FIFO circuit; however, a number of input and output pointer signals also increases. Moreover, including data converters between serial data and parallel data with a greater number of logic stages to process data conversion of a great data width causes more processing load. Thus, increasing the number of either FF circuits or latch circuits to process data with a greater data width in the FIFO circuit causes a larger area and greater power consumption.

Semiconductor device with first-in-first-out circuit


A method for communication between a base station and multiple terminal devices in a time division duplex (TDD) mode is disclosed. Prior to communicating with the multiple terminal devices by means of a plurality of frames, the base station performs semi-static configuration on a first group of subframes of the plurality of frames, by sending a system message to the multiple terminal devices, the system message carrying configuration information designating a first group of subframes in every frame of the plurality of frames as being of a first subframe type; for each frame in the plurality of frames, the base station sends downlink control information to a first terminal device of the multiple terminal devices, the downlink control information designating a second group of subframes in said each frame as being of a second subframe type.

Time division duplex (TDD) is a duplex communication technology in a mobile communication system. In a TDD system, uplink information and downlink information are transmitted at different times over a same frequency channel (namely, a carrier), and uplink and downlink channels are distinguished by time.
As a service scope expands and service flexibility increases, a communication system needs to support transmission of more types of service data. Therefore, the communication system needs to flexibly configure uplink and downlink subframes, to flexibly transmit uplink and downlink information. A TDD mode supports flexible configuration of uplink and downlink subframes. In the TDD mode, each subframe in a frame may be configured to a subframe of any type. According to different subframe types, one subframe may be an uplink subframe, a downlink subframe, a special subframe, or the like. In a special subframe, some symbols are used to transmit uplink data and some symbols are used to transmit downlink data.
In the TDD mode, a type of each subframe in a frame may be randomly set. Therefore, for two terminal devices, a subframe of one terminal device may be configured as an uplink subframe, and a subframe of the other terminal device may be configured as a downlink subframe. In this way, information that is transmitted by any one of the two terminal devices in the subframe, for example, common information, is greatly interfered with by information transmitted by the other terminal device in the subframe. The common information transmitted by one terminal device in the subframe may not be correctly received by a receive end. As a result, the receive end cannot use the common information for operating. For example, a subframe of a terminal device A may be configured as a downlink subframe, and a subframe of a terminal device B may be configured as an uplink subframe. In the subframe, the terminal device A may not receive downlink control information sent by a base station in the subframe because the terminal device B transmits uplink information in the subframe, and consequently, the terminal device A cannot normally access a network based on the downlink control information.

Subframe configuration method and apparatus


Whether a post surgery intubated patient is at risk for aspiration-based pneumonia is determined by requiring the patient to inhale an aerosol of tartaric acid that will stimulate a sensory innervation of the patient's larynx, if functionally recovered, thereby causing the patient to cough. The resulting cough or lack of cough is graded to determine whether the patient is at risk for pneumonia caused by the aspiration of matter present in the patient's mouth. In a further embodiment, the inability or difficulty of a patient to voluntarily expel potentially threatening fluid and matter from the patient's airway can be remedied by repeated applications of the aerosol chemostimulant spray.

Any patient who is to be given a general anesthetic for a surgical procedure is intubated prior to surgery. The anesthetic effectively pharmacologically suppresses brainstem function, inluding a variety of involuntary physiological responses, not the least of which is the ability to cough and clear the upper airway. These brainstem reflexes are suppressed until the anesthetic wears off. Because the tubing that has been inserted into the patient's airway tends to act like a wick--drawing fluid (e.g., secreted saliva) that may be present in the patient's mouth into the patient's airway and lungs--it is critical that the patient's involuntary cough reflex be fully functional at the time the patient is extubated.
Unfortunately, there is currently no mechanism for accurately determining whether or not the patient's ability to involuntarily clear the airway has been fully restored. Instead, because each patient's anesthesia recovery time is different, the standard medical practice is to have a skilled medical practitioner (e.g., anesthesiologist) observe the patient, and then make an `educated guess` that the patient's anesthetic state has completely subsided, and that it is `reasonably safe` to extubate the patient, and allow the patient to receive fluids and/or nutrients by mouth. If the patient's involuntary cough reflex is not yet fully restored, however, the patient is at considerable risk of developing pneumonia, as a result of entry into the airway from the patient's mouth of what would otherwise be expelled secretion and/or foreign matter that could be a substrate for breeding bacteria.
In addition, even in those cases where a patient has the ability to cough both involuntarily and voluntarily, the condition of the patient (for example in the case of coronary bypass surgery) may be such that it is extremely difficult and/or painful to have the patient cough voluntarily to clear and expel secretions, mucous and the like from the patient's airway.

Aspiration screening process for assessing post surgery patient's risk for pneumonia


A cooling fan made of synthetic resin for an air-cooled engine which is fixedly secured to a side of the body of a flywheel includes a plurality of cooling fins formed along a circumferential direction thereof, and a circular reinforcement rib projecting axially from the periphery of a backboard, thereby reducing deformation of the fan during running of the engine and preventing deformation of the fan during transportation, without significantly increasing the weight of the fan.

1. Field of the Invention
This invention relates cooling fan made of synthetic resin, and more particularly to an improved cooling fan formed as a single unit with a flywheel for a small, general-purpose air-cooled engine.
2. Description of the Prior Art
A cooling fan for a general-purpose small air-cooled engine to be used in industry, farming and so forth is conventionally made of cast iron or an aluminum alloy casting formed with a flywheel as a single unit. Recently, a cooling fan molded from thermoplastic synthetic resin material adapted to be secured to a side of the flywheel has been employed instead because there has been a demand to increase the number of cooling fins which has complicated the configuration of the cooling fins and made molding by metal casting difficult.
Referring to FIG. 4, there is shown, by way of an example, a conventional cooling fan of this type made of synthetic resin, which has been proposed by this applicant in Japanese utility model application Sho 55-70252.
In FIG. 4, the components including a flywheel body `a`, a fan of synthetic resin `a.sub.2 ` and a starting belt pulley `d` are joined together as a single unit by a plurality of bolts `g`. The reference symbol `h` represents a spacer. The flywheel body `a` and the fan `a2` are fixedly secured to a crankshaft `b` of an engine by a nut `e`. The fan `a.sub.2 ` secured to the flywheel body `a` rotates synchronously with the revolution of an engine, thereby functioning as a centrifugal blower which draws in cooling air and cools the cylinders and cylinder heads.
Other single-unit-type flywheel cooling fans comprising a cooling fan formed as a single unit with a flywheel which are different from the cooling fan of FIG. 4 have been proposed in the Japanese patent laid-open publication Hei 9-250348 or the Japanese utility model laid-open publication Hei 6-58125. According to the invention of the publication Sho 9-250348, a cooling fan made of synthetic resin is fixedly secured to a flywheel together with a starting belt pulley by a clamping bolt secured to a crankshaft. In the device of the publication Hei 6-58125, a cooling fan made of synthetic resin is fixed to a cast metal flywheel by a plurality of bolts.
Conventional synthetic resin cooling fans, such as those disclosed in the above-mentioned Japanese utility model application Sho 55-70252 (FIG. 4), the patent laid-open publication Hei 9-250348, or the utility model laid-open publication Hei 6-58125, have the disadvantage that the fans tend to be deformed as a result of softening caused by the heat produced in an engine and the negative wind pressure produced during running of the engine. As a result, the cooling fan `a.sub.2 ` bends backwardly toward an inner side (i.e., the cooling fin side) so that the cooling fan may come into contact with a wind guide plate or a cooling air duct. In the past, several proposals have been made in order to resolve this disadvantage. The spacing between the cooling air duct and the fan `a.sub.2 ` (FIG. 4) has been kept wide in one proposal from which unfavorably degrades the blowing characteristics of the fan `a.sub.2 `. Another proposal is to increase the thickness of the backboard `a.sub.3 ` of the fan `a.sub.2 ` or to dispose a reinforcement rib on a back wall of the backboard `a.sub.3 ` to increase the strength of the fan `a.sub.2 `. Still another proposal is to extend the fins toward the center to increase the rigidity of the fan `a.sub.2 `. These conventional cooling fan constructions, however, unfavorably increase the weight of the cooling fans and complicate the configurations of the fans.
In conventional cooling fans made of synthetic resin, the back wall of the backboard `a.sub.3 ` is flat, resulting in the disadvantages that it is easy for the backboard to slip, and that the fan is liable to be deformed during transportation when many fans are randomly packed into a box.


A resin main body (3) defining a bore (7) through which intake air flows, and a valve body (60) having a shaft part (20) rotatably supported by the main body (3) and a valve part (4) for opening and closing the bore (7) of the main body (3) are provided. The main body (3) is molded with the valve body (60) inserted together with a pair of bearing sleeves (24). At the time of molding the main body (3), the bearing sleeves (24) are biased in a direction opposite to the flow of the intake air with the valve body (60) being positioned in place.

A conventional throttle body is provided with a resin main body defining a bore through which intake air flows, a metal shaft part rotatably supported by the main body via a pair of metal bearing sleeves, and a valve body having a valve part for opening/closing the bore (for example, see Patent Document 1). The main body is molded with the valve body having the shaft part integrated with the valve body inserted, together with the pair of bearing sleeves.
Patent Document: JP 11-294203 A

Method of manufacturing throttle body, and throttle body


A device that provides the functionality of dual-ported memory using single-ported memory for multiple clock domains is described. In one embodiment, a memory device comprises two or more port synchronization logic devices, a port multiplexing logic, and a single-ported memory core. The port multiplexing logic devices synchronize information communicated between ports associated with the port synchronization logic devices and the single-ported memory core by synchronizing the information between port clocks and a core clock.

1. Field of the Invention
Embodiments of the present invention relate to the field of electronic circuitry. More specifically, embodiments of the present invention relate to memory where dual port operation can be emulated for applications operating according to multiple clock domains using a single port memory.
2. Related Art
Random access memory cells or RAMs have become increasingly more popular due in part to the attractive costs of these devices. Many conventional RAM cells are ordinarily only addressable from a single port. In such a memory apparatus, the input of a binary address causes a single select line or coincidence of two select lines, such as a row select line and a column select line, to cause the addressed cell to be selected. Upon selection of a cell, data may then be sensed from or written into the selected storage cell on one or two bit sense lines. Alternatively, in some RAM cells, a single selection line causes the particular cell to be selected, and other selection circuitry activated by the same address causes the bit-sense lines to be selected. However, there are generally no options for addressing, sensing, and writing. The same selection lines and the same bit sense lines are always utilized to access, write to, and sense a particular location. Consequently, a single port RAM memory device cannot be simultaneously addressed and accessed from separate sources, thus, limiting access speed at which the RAM memory may be accessed.
However, certain applications require higher memory access speeds than what a single port RAM memory device can provide. Examples of such high speed applications may be graphic related memory systems such as those used in computer display systems, data transfer and buffering devices used in high speed communications systems, and memory systems used in communication with arithmetic logic units. For such applications, multi-ported random access memory devices have been developed to provide higher access speeds and increased accessibility to the memory contents of the random access memory unit. One example of a multi-ported memory device is a dual-ported RAM cell accessible simultaneously by two independent entities. In digital integrated circuits (ICs), this implies a dual-ported memory cell that can be accessed at the same time through two different ports. Each port utilizes independent sets of addresses and control lines to access the memory array using more than one clock (referred to hereinafter as "multiple clock domains") to synchronize the data from the address and control lines.
FIG. 1 depicts a block diagram of dual-ported memory. The device 100 depicted in FIG. 1, includes a dual-ported memory 130 with two ports (110, 120). Therefore, one entity can read and/or write data to dual-ported memory 130 using port 110 while another entity may simultaneously read and/or write data to dual-ported memory 130 using port 120. Each port supports a respective address bus (112, 122) and respective buses (114, 124) for data input and output (as well as port clock lines (116, 126) for controlling the synchronization of reading and/or writing data to and/or from the port data buses (114, 124). Since, device 100 has two clock lines (116, 126) for synchronizing data input and/or output, device 100 can support "multiple clock domains," enabling the processing of large amounts of data very quickly and efficiently.
Although the dual-ported memory 100 provides an effective solution for dual-port functionality, it results in large circuit designs and high development costs. For each new generation of fabrication process technology, a new dual port cell must be designed and tested, leading to additional development costs. For the same density, a dual-ported memory 100 is approximately twice the size of a single-ported memory. As performance requirements rise, more advanced technology may be required to implement a dual-ported memory than to implement a single-ported memory, rendering the conventional dual-ported memory less attractive.
FIG. 2 depicts a block diagram of another type of dual-ported memory. As depicted in FIG. 2, the dual-ported memory 200 has a port clock domain 212, which is associated with a clock signal that is received on port clock line 224, and a memory clock domain 214, which is associated with a clock signal that is communicated on clock line 226. A clock domain boundary 262 separates the port clock domain 212 from the memory clock domain 214.
Data is received by the dual-ported memory 200 at the port data bus 222. The clock signal received on port clock line 224 is used for synchronizing data received on port data bus 222. The data that is received on port data bus 222 crosses the clock domain boundary 262 through a data first-in-first-out (FIFO) 230, which is used to synchronize the data received on port address bus 222 with the memory clock domain 214.
The data is communicated from the data FIFO 230 to a memory controller 240 along bus 232. The address logic 242 of memory controller 240 generates an address that the data may be stored at in the single clock domain memory 250. Memory controller 240 communicates the data to the single clock domain memory 250, along with the generated address, and a clock signal along the respective buses (244, 246) and control line (226). Single clock domain memory 250 stores the data at the address that address logic 242 generated.
Although device 200 is size efficient it can only be used for uni-directional data flow and is most suitable for sequential data processing.

This patent is subject to a terminal disclaimer.

Device that provides the functionality of dual-ported memory using single-ported memory for multiple clock domains


A nozzle for a mist lubricator system has an emitter head located in a tubular housing. The emitter head has tapered passageways terminating at an end from which lubricant drops are directed to a target to be lubricated. The emitter head can be incorporated in lubricator systems of various types, including those utilizing a cycling feed metering system. A nozzle constructed in accordance with the present invention can be used in reduced airflow systems and exhibits substantially lessened lubricant loss during low and no airflow periods.

The provision of lubrication to a particular location in an apparatus, such as a knitting machine, loom, or the like, is often required. Such lubrication is often provided by a lubricant mist directed towards the targeted area, but the stream is often difficult to direct with accuracy. The lubricant provided by a mist system also often coagulates into drops of various sizes. The presence of a spray of drops having a range of sizes impedes control over the amount of lubricant dispersed and its accurate delivery. Other systems dispense a pulsed series of lubricant "slugs" or drops of varying size.
In U.S. Pat. No. 5,639,028 to the present inventor and assignee, an improved nozzle apparatus for use in lubricant mist systems is disclosed. The nozzle set forth therein generates a lubricant stream of small, consistently sized drops that can be accurately directed to a part to be lubricated. Dripping from the nozzle is substantially eliminated, and the nozzle can be used over a wide range of air pressures, including reduced airflow lubrication systems of the aerosol type.
Mist generator systems in which the nozzle of the '028 Patent are employed may have a plurality of nozzles connected to a single generator, with the number of nozzles approaching 30 in number. With increasing energy costs, the cost of providing compressed air to such a plurality of nozzles can be a considerable operational expense. While limiting the amount of air passing through the nozzle would appear to be an obvious solution to such increasing costs, insufficient extraction of lubricant from the aerosol can occur as the air pressure is lowered, leading to excessive lubricant loss and thus mitigating the value of the nozzle apparatus.
The cycling of air through a plurality of nozzles can also conserve the amount of air required. U.S. Pat. No. 6,571,918 discloses a lubricant distributor that meters lubricant into precise individual volume amounts and directs individual volumes to a distribution and spray system. Such cycling systems can lessen air costs, but can lead to lubricant accumulation and run-off through a nozzle when the airflow is either off or below the designed operational threshold pressure for the nozzle. Such run-off results in lubricant loss as well as insufficient lubrication for the targeted area.
It is accordingly a purpose of the present invention to provide a new and improved nozzle assembly particularly adapted for use in reduced airflow situations in oil mist lubrication systems of the type disclosed in the '028 Patent.
A further purpose of the present invention is to provide a nozzle of the general type disclosed in the '028 Patent in which lubricant loss is substantially lessened, if not eliminated, during low airflow and no airflow periods.
Yet a further purpose of the present invention is to provide an emitter head for mist lubrication nozzles, such as those of the type set forth in the '028 Patent, that allows the nozzle to meet the aforementioned purposes and goals.
Yet a further purpose of the present invention is to provide a nozzle and emitter head which are of simple and economical construction, and which can be used in connection with existing lubricator equipment, including those of the type utilizing a cycling feed-type metering system, such as set forth in U.S. Pat. No. 6,571,918.


A motor controller stores values corresponding to predetermined equivalent resistance which corresponds to power loss generated by switching on and off switching elements. Voltage command values are determined by adding voltage drop values determined from values corresponding to the equivalent resistance and values of current flowing in the switching elements to target applied voltage values corresponding to current command values which correspond to target output of a motor. The switching elements arranged in a power supply line to the motor are switched on and off by control signals generated according to the voltage command values.

In a motor controller comprising switching elements such as MOS-FETs or the like arranged in a power supply line to a motor, current command values corresponding to target output of the motor are determined, target applied voltage values to the motor are calculated based on the current command values, PWM control signals having duty cycle corresponding to the target applied voltage values are generated, and the output of the motor is controlled by switching on and off the switching elements constituting an inverter circuit with the PWM control signals (Japanese Laid-open Patent No. 2001-268980).


A process for inerting an interior of a container, the process comprising:. (a) introducing an inert fluid rich stream into the interior of the container, the concentration of inert fluid in the inert fluid rich stream inert fluid being greater than the inert fluid concentration in the interior of the container; PA0 (b) increasing the concentration of inert fluid in the inert fluid rich stream during its introduction into the interior of the container; and PA0 (c) withdrawing or purging a waste gas stream containing at least one impurity and inert fluid from the interior of the container.

Inert fluids, particularly inert gases, are useful for controlling the atmosphere of the interior of a container or a vessel. Of these inert fluids, nitrogen gas is commonly utilized for inerting, for example, the interior of a container which is useful for transporting perishable goods or manufacturing semiconductor chips. To supply nitrogen or other inert gases to the interior of a container, various inert gas sources have been utilized. Some of these inert gas sources include cylinders, liquid tanks, membrane gas separation plants and pressure-swing or temperature-swing adsorption plants. The selection of a particular inert gas source for a particular inerting process, however, is dependent on the rate of inerting the interior of a container and the energy (power) consumption associated with the inerting inasmuch as they play important roles in commercial operations. Thus, there is a need to increase the rate of inerting the interior of a container while reducing the power cost associated with the inerting process, regardless what inert gas sources are employed.


Techniques are disclosed for modeling costs when editing a workflow process model. A request may be received to assign a cost factor to a workflow process step of the workflow process model. Responsive to the request, the cost factor may be assigned to the workflow process step, such that a traversal of the workflow process step by a transaction invoking the workflow process model results in the cost factor being included in a total cost to be charged for executing the transaction.

Advances in computer technology are allowing many organizations to move towards a service-oriented architecture (SOA), where data flows and business logic of an organization are implemented using assemblies of web services. In general, web services are software components capable of being accessed via standard network protocols using a standardized messaging system. Such web services are typically capable of exchanging data with software applications that are written in various programming languages running on various platforms, thus enabling platform independent implementations of data flows and business logic of an organization.
In practice, an individual may utilize workflow modeling and runtime technologies and corresponding standards such as Business Process Execution Language (BPEL) to enable workflow-oriented applications, in which each business process is modeled as a workflow process model, also referred to as a workflow. A workflow is a series of steps involving a mix of services (software and human-provided) that may then be deployed and executed on a number of vendor provided, workflow runtime platforms, such as the IBM® WebSphere® Process Server. For example, a workflow may be a number of loosely coupled web services sending and receiving messages to perform an overall (business) process. A business process expert may link and sequence web services, in a process known as orchestration, to meet a new or existing business requirement. Workflow-oriented applications are central to the SOA pattern and allow a set of generic software services to be used in a variety of different combinations to solve an ever evolving set of business needs.

International Business Machines Corporation


The present invention provides synthetic ribozyme oligonucleotides alone and within constructs. The ribozyme gene provides methods for the treatment of prostate hyperplasia and other androgen dependent pathologies. Improved therapies for such diseases are provided without significant hormonal imbalance and without surgical intervention. Also provided are techniques for selecting and synthesizing effective and specifically targeted molecular tools for use in inhibiting androgen receptor gene expression.

The present invention relates to the field of selective inhibition of androgen receptor. The invention further relates generally to the field of gene therapy, and particularly gene therapy in the treatment of prostatic cancer.
The prostate gland is an androgen-dependent organ and continues to grow with age. This leads to enlarged prostate in older men with consequent pathological manifestations. Androgen receptor is the principal mediator of prostatic growth.
A hammerhead ribozyme is a small RNA capable of cleaving a target RNA in a catalytic manner in the presence of a divalent cation (Pyle, 1993). Naturally occurring hammerhead ribozymes were discovered in certain plant viroids and viruses (Forster and Symons, 1987). The hammerhead ribozyme acts in xe2x80x9ccisxe2x80x9d during viral replication by the rolling circle mechanism. However a hammerhead ribozyme was engineered to cleave in xe2x80x9ctransxe2x80x9d against other RNAs (Uhlenbeck, 1987). A hammerhead ribozyme consists of antisense segments (stems I and III) and a catalytic domain (stem II). It can be designed to target specific mRNAs by selecting sequences flanking the catalytic element. The only requirement for the target substrate is the sequence HUX (H can be any nucleotide, X is A, C or U), where cleavage occurs after X (Haseloff and Gerlach, 1988). Hammerhead cleavage produces RNA products with 5xe2x80x2 hydroxyl and 2xe2x80x2, 3xe2x80x2 cyclic phosphate termini (Buzayan, et al., 1986; Prody, et al., 1986). A hammerhead ribozyme has potential therapeutic applications, e.g., it inactivates specific RNAs in vivo, such as HIV-1 gene expression (Sarver, et al., 1990; Ojwang, et al, 1992; Yu, et al., 1993), RNAs responsible for other viral infections (Chen, et al., 1992; Sullenger and Cech, 1993; Tang, et al., 1994) and the RNA transcripts of other genes (Scanlon, et al., 1991; Kashani-Sahetet, et al., 1992; Lange, et al., 1993; Ha and Kim, 1994; Kobayashi, et al., 1994; Sioud, et al., 1994; Jarvis, et al., 1996; Ohta, et al., 1996; Sioud, 1996).
Androgen receptor (AR) is a ligand-activated transcription factor belonging to the steroid/thyroid hormone receptor superfamily (Evans, 1988; Beato, 1989). AR plays an important role in the coordination of the male-specific sexual phenotype and in the development of the male-reproductive organs such as the prostate gland (Quiley, et al., 1995). AR is expressed in various cells and tissues (Chang, et al., 1995; Roy and Chatterjee, 1995). It has also been considered as an etiologic factor for human benign prostatic hyperplasia (Brolin, et al., 1992; Wilding, 1992; Lepor, et al., 1993). Furthermore, AR gene mutations are involved in primary and secondary prostate cancer (Newmark, et al., 1992; Culig, et al., 1993; Suzuki, et al., 1993; Taplin, et al., 1995). A high expression of AR in recurrent prostate cancer cells and metastatic prostate cancer cells has also been observed (Taplin, et al., Viskarpi, et al., 1995; Umeki, et al., 1996). However, how the AR regulates differentiation and development of the male reproductive organs and its role in prostatic diseases are not known.
Clinical treatment of prostatic cancer has included the use of surgical techniques to remove enlarged prostate tissue, or the use of enzyme inhibitors such as PROSCAR(trademark). PROSCAR inhibits 5-alpha reductase, which is the enzyme that converts testosterone to dihydrotestosterone. The abolition of testesterone itslf to induce androgen action limits the use and effectiveness of this therapy. These approaches are thus undesirable in many patients. Need continues to exist in the medical arts for a therapy that provides a more targeted approach to treatment of this pathology.
Androgen receptor plays a central role in the development, differentiation and maintenance of the male reproductive organs (Coffey, 1988; Griffin et al., 1989; Migeon et al., 1994). It is also involved in prostate disorders and other diseases (Edward, 1992; Macke et al., 1993; Qingley et al., 1995). The molecular mechanisms whereby AR regulates the physiological and pathological events are not clearly understood (Wilding, 1992; Lapor and Lawson, 1993). Hence, there has been no significant development of clinical approaches for treatment of prostate and related disorders.
The present invention describes inactivation of AR gene expression by engineering hammerhead ribozymes to cleave specific sites in AR mRNA. The present in vitro studies of hammerhead ribozymes reveal a high efficiency of such cleavage activity. The hammerhead ribozymes suppress AR mRNA expression in cultured cells.
Included in the present invention are hammerhead ribozymes that can selectively and efficiently degrade human androgen receptor messenger RNA. Also part of the present invention are expression vectors containing the gene for a ribozyme that, when introduced into a human prostate cancer cell, is capable of abolishing the androgen receptor mediated transactivation of a reporter gene. Targeting of the ribozyme gene into specific tissues of transgenic mice can be done to produce tissue-specific inactivation of androgen receptor. Therapeutic use of the ribozymes of the present invention to suppress androgen action in human clinical conditions such as the prostatic hyperplasia may be accomplished in vivo of the present invention.
The following provides three selection criteria in identifying and designing synthetic ribozyme of the present invention:
Based on these three selection criteria, the inventors designed three hammerhead ribozymes and tested their effectiveness in the in vitro endonuclease assay. One of these ribozymes, HR-2 was found to be particularly highly effective in selectively degrading the androgen receptor mRNA. This androgen receptor degrading ribozyme is more active than all ribozymes reported in the literature.
After eliminating sequence regions that can potentially form secondary structures or have significant homology to heterologous mRNAs, the inventors chose three structural domains of the AR mRNA with high AU contents as targets for the hammerhead ribozyme.
Hammerhead ribozymes are composed of two functionally distinct components; (i) the central catalytic core usually containing about 24 nucleotides with a conserved stem loop structure, and (ii) two variable specifier sequences on both 5xe2x80x2 and 3xe2x80x2 sides of the catalytic core that are complementary to the target RNA. The three targeted areas on the AR mRNA that were selected correspond to (i) transactivation domain of the rat AR (ribozyme, R-1), (ii) transactivation domain of the human AR (ribozyme, H-1), and (iii) the DNA binding domain of the human AR with 95% homology to the rat AR (ribozyme, HR-2). All three of these ribozymes contained 9-12 nt long specifier arms on each side of the catalytic core. Both ribozymes and truncated AR targets were cloned into the Bluescript vector and were transcribed with either T7 or T3 RNA polymerase for the in vitro endonuclease assay. At an equimolar enzyme-substrate ratio and at 37xc2x0 C., R1 and H1 required xcx9c4 hr for 75 to 100% cleavage of the substrate. The ribozyme HR-2 required less than 30 min for complete cleavage of the target substrate. The HR-2 ribozyme was also effective at a E:S ratio as low as 1:50. A mutant HR-2 containing two base substitutions within the catalytic core was enzymatically inactive and the wild type HR-2 did not act on substrates corresponding to R-1 and H-1, substantiating the specificity of the ribozyme function.
The inventors examined the effectiveness of the HR-2 in AR(xe2x88x92) PC3 (prostate cancer derived) cells transfected with the AR expression vector and a reporter construct containing MMTV-CAT. In this transfection assay an expression vector containing the HR-2 ribozyme was able to inhibit the AR mediated transactivation of the MMRV-promoter in a dose-dependent manner with a more than 95% inhibition at an AR:HR-2 ratio of 100. These results indicate that ribozymes can be an effective means for inactivating androgen action and are useful as a therapeutic agent when delivered to the target tissue through expression vectors and tissue-specific promoters.
By means of selection of the target base compositions (A-T, G-C pairs), the optimum size of the two sided arms, and the in vitro testing of various ribozyme constructs, the inventors have produced particular synthetic ribozymes having high activity and specificity for the human androgen receptor mRNA.
The inventors have developed the specifically active ribozyme HR-2 (SEQ ID NO:2) that cleaves the human androgen receptor mRNA (SEQ ID NO:1) at base positions 2374/2375 (Table 1). The nucleotide structure of the rat ribozyme (SEQ ID NO:1) and its complementarity to the rat androgen receptor mRNA target site (SEQ ID NO:10) are as follows:
The in vitro cleavage of AR mRNA sequence by the ribozyme and kinetics of the endonuclease activity have established utility of the present invention.
Mammalian expression vectors containing the ribozyme HR-2 and a RNA polymerase II promoter derived from the cytomegalovirus (CMV) or a RNA polymerase III promoter derived from the gene for a small nuclear RNA (U6 RNA) when cotransfected into human (PC-3, prostate cancer derived) and rodent (3T3, mouse fibroblast derived) cells showed a dose-dependent inactivation of androgen receptor function.
This involved establishing:
i) Cell transfection system.
ii) Inhibition in the human prostate cancer cells by the CMV construct; and
iii) Inhibition in the NIH 3T3 cells by the U-6 construct
A transgenic mouse line containing selective over-expression of the androgen receptor in the liver targeted by the liver-specific phenylalanine hydroxylase gene promoter has been created by the present inventors. The same promoter is being used to target the HR-2 ribozyme to the liver. The homozygous AR transgenic mouse will be crossed with the HR-2 transgenic mice and the hepatic level of the androgen receptor in the hybrid mice will be monitored.
Gene therapy to suppress prostatic hyperplasia during old age and to destroy aberrant forms of androgen receptor mRNA in prostate cancer cells is thus available. This may involve therapeutic use of the ribozyme to suppress prostatic hyperplasia. Such can be performed by local delivery of the ribozyme gene construct inserted into any one of the emerging in vivo gene delivery vectors (for the most recent development see, Naldini et al., 1996) during cauterization of the enlarged prostate. At an advanced stage of prostate cancer the androgen receptor undergoes mutation and begins to function independent of the androgenic ligand (Taplin et al., 1995). Presently no specific therapeutic means to inhibit such an androgen-independent form of the receptor is available. The HR-2 ribozyme inserted into the appropriate delivery vector can be an effective drug to control such androgen independent mutant form of the receptor and to inhibit the resultant neoplastic prostate cell growth.
The present inventors demonstrate that two hammerhead ribozymes are able to cleave the RNA immediately following the GUC triplet sequences at positions 1393 and 2209 of the AR mRNA, respectively. Compared to a variety of other triplets, the GUC triplet preceding a particular site on the RNA substrate makes that site much more efficiently cleaved. (Haseloff and Gerlach, 1988; Ruffner et al., 1990; Shimayama et al., 1995; Hendrix et al., 1996). It can be demonstrated that the RNA phosphodiester bond immediately following the nucleotide residue, which has its ribose sugar group held in a south conformation (that is C2.,-endo xe2x80x94C3,-exo) is most preferably cleaved by the hammerhead ribozyme (Plavec et al., 1994). Furthermore, compared to other nucleotidyl 3xe2x80x2-ethylphosphates, cytidine 3xe2x80x2-ethylphosphate can most readily assume the south conformation at the ribose moiety, thus explaining the preference for C at the third base of the triplet preceding the cleavage site (Plavec at el., 1994). That G is the preferred first base in the marker triplet follows from the analysis of Kcat and Km of the cleavage reactions using substrate in which the first base is changed from G to another base (Shimayama et al, 1995). The base preference at the first position of the triplet, despite its distance from the cleavage site, indicates that the entire triplet contributes to the structure of the transition state intermediate formed during the phosphodiester bond cleavage reaction (Hendrix et al, 1996).
Specificity and efficiency are also important parameters to consider in designing a hammerhead ribozyme. Factors, such as the secondary structure of the substrate and length as well as composition of the flanking sequences (stems I and III) of hammerhead ribozymes affect function. Many studies have shown that a hammerhead ribozyme targeted to a predicted open stemloop structure within target RNA substrate is more effective in catalyzing cleavage of the RNA substrate when it targets a base paired region (L""Huillier et al., 1992; Steinecke et al., 1994; Hendrix et al., 1996; Lieber and Strauss, 1996). Christoffersen and Marr found that this criterion applies well to ribozyme activity in cell culture and animal studies (Christoffersen and Marr, 1995). The length and composition of flanking sequences of a hammerhead ribozyme are also important factors in optimizing a designed hammerhead ribozyme. Although the length of the flanking sequences of the hammerhead ribozyme varies in different target sites, optimal cellular efficiency is observed with relatively short sequences of between 10-20 residues (Fedor et al., 1990; Herschlog, 1991; Heidenreich and Eckstein, 1992; Ferbeyre et al., 1996; Jarvis et al., 1996). Up to a point (xcx9c25 residues), longer flanking sequences can increase specificity of the hammerhead ribozyme, but it also decreases the cleavage efficiency, due to a decrease in turnover of the ribozyme (Heidenreich and Eckstein, 1992; Bertrand et al., 1994; Ferbeyre et al., 1996). This is supported by the further finding that reduced length of the flanking sequences between substrate and hammerhead ribozyme increases the rate of cleavage (Goodchild and Kohli, 1994). Composition of the flanking sequences is another consideration. A target region of RNA substrate with a high number of G or C residues so stabilizes interaction between the target and ribozyme that their separation after cleavage may be deterred (Bertrand et al., 1994). It is therefore preferable to select A/U rich flanking sequences since A:U base pair is weaker than G:C. Additionally, A-rich sequences in the flanks of the hammerhead ribozyme avoid the possibility of U-G wobble base pairing that can decrease discrimination between target sites (Hersalag, 1991; Bertrand et al., 1994). The MFOLD program was used to study the secondary structure of AR mRNA (Zuker and Stiegler, 1981; Zuker, 1989). Two cleavage sites of AR mRNA with open-loop or single-stranded regions were identified. The open regions contain GUC triplet sequences flanked by U-rich sequences that are not homologous to other gene sequences. Flanking sequences with 19 nucleotides and 18 nucleotides (stems I and III) were selected for HI and HR2 hammerhead ribozymes (FIG. 1) that contain 58% and 61% A/U-rich sequences, respectively. In the assay system, these hammerhead ribozymes were highly specific and catalyzed cleavage of only the AR mRNA substrate (FIG. 7).
Highly specific hammerhead ribozyme activity has been observed in cultured cells, and in animals (Saxena and Ackerman, 1990; Sullenger and Cech, 1993; Yu et al., 1993; Larsson et al., 1994; L""Hulillier et al., 1996). L""Hulillier et al. (1996) have observed that a hammerhead ribozyme cleaves only exogenous xcex1-lac mRNA against which it was designed, and not against endogenous xcex1-lac mRNA in transgenic mice, indicating the specificity of designed hammerhead ribozyme. In addition to these demonstrated specificities, the cleavage rate of both the HI and HR2 ribozymes is rapid and complete within 30 min at 1:1 molar ratio of ribozyme: substrate. However, compared to HI, HR2 is more efficient in vitro (FIG. 5) and in vivo (FIG. 8). The reason for the higher activity of HR2 over HI is not clear. One explanation could be that the target region in the AR mRNA for HR2 is more exposed than the target region for HI, so that HR2 has a better access to its RNA substrate (Kobayashi et al., 1994).
The following table enumerates several sequences that were used in the testing or development of the present invention.

Ribozyme mediated inactivation of the androgen receptor

Board of Regents, The University of Texas System


Catalyst compositions and methods for F-T synthesis which exhibit high CO conversion with minor levels (preferably less than 35% and more preferably less than 5%) or no measurable carbon dioxide generation. F-T active catalysts are prepared by reduction of certain oxygen deficient mixed metal oxides.

Fischer-Tropsch (F-T)synthesis involves the catalytic reductive oligomerization of carbon monoxide in the presence of hydrogen as follows:
where n is an integer and (CH2)n represents hydrocarbons (paraffinic and olefinic), with an enthalpy of reaction of −165 kJ/mole (P. F. Schubert et al. (2001) "Studies in Surface Science and Catalysis 136: natural Gas Conversion VI,". E. Iglesia et al. (eds.) Elsevier, Amsterdam p 459.) Generally, the process converts a mixture of CO and molecular hydrogen into a mixture of hydrocarbons, including saturated hydrocarbons and olefins. Oxygenated hydrocarbons, such as alcohols, and sometimes aromatics may also be formed in a F-T process. More specifically, products of F-T processes can include gaseous, liquid, heavy oil, and wax products which can be further upgraded to various fuels (gasoline, jet fuel, diesel fuel, etc.) and other value-added hydrocarbon products, particularly liquid hydrocarbons.
A mixture of CO and hydrogen for the F-T process can be generated in a number of ways, and in particular can be synthesis gas "syngas." Syngas is available from a variety of sources and can, for example, be prepared by coal, biomass, or waste gasification processes or can be produced from methane, for example by steam reforming or partial oxidation. The ratio of H2 to CO in syngas from a given source may vary significantly (e.g., from about 0.3 up to 3 or higher) and a given F-T catalyst may be sensitive to that ratio (i.e., exhibit increased or decreased activity or changes in selectivity dependent upon that ratio.)
While a number of metals demonstrate F-T activity, only four metals: Fe, Co, Ru, and Ni are regarded in the art as usefully active. The utility of F-T catalysts is decreased if they exhibit high methanation activity. High levels of catalytic methane formation from CO and hydrogen by a catalyst as in the reaction:
decreases the utility of that catalyst for formation of higher hydrocarbons. For example, the utility of Ni on conventional metal oxide supports as an F-T catalyst is decreased by its high methanation activity. In contrast, Ni supported on some molecular sieves such as zeolite Y does not exhibit high methanation activity making it a more useful F-T catalyst.
The mechanism of the F-T catalytic reaction is dependent upon the catalyst employed. Some metals may dissociatively adsorb CO and others associatively adsorb this molecule. The tendency for dissociative adsorption increases on going from right to left on the Periodic Table. For example, iron dissociatively chemisorbs CO and, as a consequence, the active phase of the catalyst is not metal, but is generally regarded as a metal carbide phase (C. N. Satterfield (1991) "Heterogeneous Catalysis in Industrial Practice," McGraw-Hill, New York p. 432.) In contrast, cobalt associatively adsorbs CO, with hydrogenation of the adsorbed CO to CHx fragments. The olefin reabsorption and CO hydrogenation models have been used to describe the F-T system and explain many of the features that have been observed. (E. Iglesia et al. (1993) in "Computer Aided Design of Catalysts," E. R. Becker, et al. (eds) Marcel Dekker, New York p. 199.)
Features of established catalytic systems for F-T synthesis are summarized hereafter. Iron and cobalt-based systems have generally received more attention and certain of these systems have been commercialized. Iron and cobalt based systems have their origins with Fischer and Tropsch who developed alkalized iron turning- and Kieselguhr-supported cobalt/magnesia (or thoria) catalysts (See: F. Fischer and H. Tropsch (1923) Brennst. Chem. 4:276 and F. Fischer and H. Tropsch (1925) German Patent 484,337) Iron-based and cobalt-based catalysts each have advantages for use in appropriate circumstances. Iron-based catalysts are typically employed, for example, where H2:CO ratios are low (e.g., 0.5 to 1.5) as might be found in coal or biomass systems. In contrast, cobalt-based catalysts are more appropriately employed when H2:CO ratios are high (>1.5) which would typically be found in natural gas-to-hydrocarbon liquids applications.
Advantages of iron-based catalyst are generally lower cost, relative insensitivity to reaction conditions, such as H2:CO ratio and the presence of low levels of sulfide impurities; and their ability to function at low H2:CO ratios. Cobalt-based catalysts are considerably more expensive and can show strong sensitivity to H2:CO ratio. However, cobalt-based catalysts, in general, exhibit higher overall activity and increased mechanical strength compared to iron-based catalysts. Additionally, under like conditions, cobalt-based catalysts tend to produce a distribution of hydrocarbons that is more heavily weighted toward high carbon number species (i.e., give a higher chain growth probability, α) than the hydrocarbon distribution produced using iron-based catalysts. Iron-based F-T catalysts can also produce copious quantities of carbon dioxide in the F-T process, which is generally detrimental, because they can exhibit activity as an internal forward water-gas-shift catalyst.
The utility of F-T synthesis catalysts is significantly decreased if there is significant conversion of CO to CO2 rather than to value-added hydrocarbon and oxygenated hydrocarbon products. Preferred F-T synthesis catalysts exhibit low CO2 production particularly in combination with high CO conversion rates. An F-T catalyst may exhibit product selectivity for a desirable product composition. For example, certain F-T catalysts exhibit selectivity for production of higher molecular weight hydrocarbons, for production of low molecular weight hydrocarbons (e.g., low molecular weight olefins), for production of product with higher or lower amounts of olefinic materials, or for the production of product with higher or lower amounts of oxygenated materials (e.g., alcohols). Product selectivity of an F-T catalyst can be a significant factor in the utility of that catalyst for a given application.
The design and selection of F-T catalysts for low CO2 production and selective applications should consider the following composition related issues: whether the mechanism of adsorption of CO to the catalyst is associative or dissociative; the relative strengths of adsorption of CO and hydrogen to the catalyst; the redox activity or ease of reducibility of metals which is related to their activity for water-gas-shift reaction; the presence of strong or elastic bonds between component atoms of the catalysts support (if any), leading to larger elastic constants and higher mechanical strength of the catalyst support or support framework. Additionally, F-T synthesis can strongly depend on catalyst morphology, e.g., pore size, pore size distribution and particle size of the catalyst, because of the influence of such parameters on mass transport, and on the coupling between mass transport and chemical reaction. An additional factor that can be considered is catalyst acidity, because this property is expected to strongly influence hydrocracking activity by a catalyst, which is preferably to be avoided.
F-T synthesis is a process that involves an unusually high degree of interaction between reaction chemistry, catalyst properties, mass transport, reactor design, overall system integration, and economics. Catalyst selection and reactor design for a given F-T application depends upon all of these factors. For example, a cobalt catalyst may be appropriate for natural gas conversion to liquid hydrocarbons where its advantages in increased activity and longevity are beneficial. Because cobalt catalysts are sensitive to feed composition (i.e., H2:CO ratio), the F-T system employing the cobalt catalyst may then require a water-gas-shift module upstream of the F-T catalyst when low hydrogen content sources (such as coal) are used to ensure that the appropriate H2:CO ratio is provided. In contrast, unsupported baseline precipitated iron catalysts may not be amenable for use in slurry phase or fluidized bed reactors because of their lower mechanical strength and correspondingly high attrition rate, but would be preferred in other applications because of their relative insensitivity to H2:CO ratio and their product selectivity characteristics (i.e., greater selectivity for production of C5 or higher products at low H2:CO ratios). There is a continuing need in the art for catalysts for F-T synthesis which exhibit one or more beneficial characteristics for a given application, given H2/CO feedstock, given reactor design, and/or a desired product composition.
A large number of F-T catalysts are known in the art. The description that follows provides a brief summary of such catalysts.
U.S. Pat. No. 6,602,921 (Manzer) reports catalysts useful in a F-T process for producing hydrocarbons which comprise certain metals, i. e. cobalt, iron, nickel, or ruthenium and combinations thereof, in addition to silver supported on a catalyst support, such as alumina, zirconia, sulfated zirconia, tungsten oxide-doped zirconia, MCM-41, zeolites, clays, titania or silica. Catalytic activity is reported to be increased by the addition of silver.
U.S. Pat. No. 6,537,945 (Singleton et al.) reports an F-T catalyst comprising a gamma-alumina support doped with lanthanum oxide and barium oxide for increased thermal stability in a slurry bubble column reaction system and containing cobalt promoted with ruthenium as the active catalyst component. Catalyst activities are expressed in g-HC/Kg-cat/hr. (grams of hydrocarbon produced per gram of catalyst per hour), a measure of hydrocarbon productivity.
U.S. Pat. No. 6,515,035 reports a catalyst comprising at least one metal from Groups 8, 9 or 10 of the Periodic Table (IUPAC) impregnated on a modified alumina support that is pre-reduced using at least one reducing compound, for example selected from the group formed by hydrogen, carbon monoxide and formic acid, optionally mixed with an inert gas, for example nitrogen, in a reducing compound/(reducing compound+inert gas) mole ratio in the range of 0.001:1 to 1:1. The reduction may be carried out in the liquid phase with the catalyst suspended in an inert liquid phase.
U.S. Pat. No. 6,313,062 relates to the preparation of an F-T catalyst comprising a Group VII noble metal and an "Iron Group metal" (preferably cobalt) on a support. The catalysts are reported to have "high activity."
U.S. Pat. Nos. 6,271,432 and 6,191,066 relate to F-T catalysts which are non-promoted cobalt catalysts supported on alumina which is preferably doped with titanium. U.S. Pat. No. 6,262,132 relates to a method for producing an attrition-resistant catalyst which employs an attrition-resistant support that is a titanium-doped gamma alumina. U.S. Pat. No. 6,100,304 relates to F-T catalysts which are certain supported palladium promoted cobalt catalysts. U.S. Pat. No. 5,939,350 relates to processes and catalysts for F-T synthesis in a slurry bubble column reactor (SBCR). The patent reports the use of certain non-promoted cobalt catalysts and certain palladium-promoted cobalt catalysts in the SBCR.
U.S. Pat. No. 5,856,365 relates to the preparation of a catalyst useful for conversion of synthesis gas wherein the catalyst comprises cobalt, ruthenium and either scandium or yttrium on an inert support. The support can be selected from at least one oxide of at least one of Si, Ti, Al, Zr, Zn, Mg, and Sn.
U.S. Pat. No. 5,728,918 reports a catalyst comprising cobalt on a support, used for conversion of synthesis gas with an H2:CO ratio of 1-3, preferably 1.8-2.2, to C5+ hydrocarbons at a pressure of 1-100 bar and at a temperature of 150-300° C., at a typical gas hourly space velocity of 1000-6000 v/hr/v. This catalyst is reported to be regenerated by contacting it with a gas containing carbon monoxide and less than 30% hydrogen, at a temperature more than 10° C. above Fischer-Tropsch conditions and in the range 100-500° C., and at a pressure of 0.5-10 bar, for air, at least 10 minutes, preferably 1-12 hours. The contact time period depends on temperature and gas hourly space velocity. This patent also reports an activation procedure, which may include a first step of contacting the catalyst with a gas containing molecular oxygen, preferably air at 200-600° C., at atmospheric pressure, for more than 30 minutes, and preferably for 1-48 hours.
U.S. Pat. Nos. 5,292,705 and 5,389,690, both to Mitchell, describe a fresh, previously reduced hydrocarbon synthesis catalyst activated by contact with hydrogen at elevated temperatures and pressures and in the presence of liquid hydrocarbons, preferably, sufficient to immerse the catalyst therein.
U.S. Pat. No. 5,292,705 relates to a method for activating a hydrocarbon synthesis catalyst by treating a reduced, "essentially fresh" (unused) catalyst with hydrogen in the presence of hydrocarbon containing liquids. The method is exemplified with a titania/alumina supported Co-Re catalyst.
U.S. Pat. No. 5,248,701 (Soled et al.) relates to a copper-promoted cobalt manganese spinel catalyst useful in F-T synthesis. The spinel is described as having the formula: Co3-xMnxO4, where x is from 0.5 to about 1.2. The patent also reports the formation of this cobalt-manganese mixed metal catalyst in an acidic aqueous solution containing alpha-hydroxy carboxylic acids rather than in alkaline solution to provide the spinel with high BET surface area of at least 5 m2/g. The copper promoter is reported to be preferably present in the catalyst from about 0.1 to about 5 gram atom %. While a relatively high level of CO conversion is reported for the catalysts tested, a significant amount of the CO was converted to carbon dioxide. This patent provides a brief description of several additional U.S. patents which relate to iron-cobalt spinel catalysts for F-T synthesis, including U.S. Pat. Nos. 4,518,707; 4,584,323 and 4,607,020, which relate to iron-cobalt spinels for selective conversion of syngas to alpha-olefins and where the spinels may be reduced and carburized, copper-promoted or carbided in situ, U.S. Pat. Nos. 4,537,867; 4,544,672 and 4,544,674, which relate to iron-cobalt spinels containing low levels of cobalt for selective conversion of syngas to low molecular weight (C2-C6) olefins and where the spinel may be promoted or reduced and carbided.
U.S. Pat. No. 5,140,050 (Mauldin et al.) relates to catalysts useful in F-T synthesis which are prepared on binder-containing titania supports. Catalysts are prepared by dispersing catalytic amounts of metal or metals, on the support. Preferred metals are cobalt or a combination of cobalt with another metal.
U.S. Pat. No. 5,145,876 (Shutt) reports a F-T catalyst that is ruthenium metal supported on a high surface area support and which is promoted employing bromine moieties. The preferred support is gamma-alumina. The specific source of ruthenium and bromine for catalyst preparation is disclosed as an aqueous solution of ruthenium bromide, such as ruthenium tribromide.
U.S. Pat. No. 4,861,802 (McCann) reports a modified F-T process utilizing certain perovskite catalysts for the synthesis of low molecular weight olefinic hydrocarbons. The catalyst comprise a perovskite oxide of the empirical formula AB1-a Fea O3, wherein A is selected from cations of the alkali metals, alkaline earth metals, lanthanides, Th or U, B is selected from cations of certain transition metal or main group elements (Al, Ga, In, TI, Ge, Sn, Pb, Sc, Y, Ti, Zr, HF, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, or Hg) and a is within the range 0.01 to 1. The perovskites tested exhibited at most about 8% conversion of CO with a large amount of the converted CO going to CO2.
U.S. Pat. No. 4,738,948, issued on Apr. 19, 1988, describes a catalyst comprising cobalt and ruthenium at an atomic ratio of 10-400, on a refractory carrier, such as titania or silica. The catalyst is used for conversion of synthesis gas with an H2:CO ratio of 0.5-10, preferably 0.5-4, to C5-C40 hydrocarbons at a pressure of 80-600 psig and at a temperature of 160-300° C., at a gas hourly space velocity of 100-5000 v/hr/v. This catalyst is reported to be regenerated by contacting it with hydrogen gas at 150-300° C., preferably 190-260° C., for 8-10 hours.
U.S. Pat. No. 4,595,703 reports a catalyst comprising cobalt or thoria promoted cobalt on a titania support, used for conversion of synthesis gas with an H2:CO ratio of 0.5-4, preferably 2-3, to C10+ hydrocarbons at a pressure of preferably 80-600 psig, and at a temperature of 160-290° C., at a gas hourly space velocity of 100-5000 v/hr/v. This catalyst is reported to be regenerated by contacting it with hydrogen gas, or a gas which is inert or non-reactive at stripping conditions such as nitrogen, carbon monoxide, or methane, at a temperature substantially the same as Fisher-Tropsch conditions. If it is necessary to remove coke deposits from the catalyst, the catalyst can be contacted with a dilute oxygen-containing gas, at oxygen partial pressure of at least 0.1 psig, at 300-550° C., for a time sufficient to remove coke deposits, followed by contact with a reducing gas containing hydrogen, at a temperature of 200-575° C. and at a pressure of 1-40 atmospheres, for 0.5-24 hours.
U.S. Pat. No. 4,585,798 reports a catalyst comprising cobalt and ruthenium in an atomic ratio greater than about 200:1 and, preferably, a promoter, such as a Group IIIB or IVB metal oxide, on an alumina support, used for conversion of synthesis gas to hydrocarbons at a pressure of preferably 1-100 atmospheres and at a temperature of 160-350° C., at a gas hourly space velocity less than 20,000 v/hr/v, preferably 100-5000 v/hr/v, especially 1000-2500 v/hr/v, which is reported to be activated prior to use by reduction with hydrogen gas, followed by oxidation with diluted air, followed by further reduction with hydrogen gas.
U.S. Pat. No. 4,544,671 (Soled et al.) relates to F-T synthesis catalysts which are slurried high surface area iron-cobalt spinels and to a slurry process employing the catalysts. The catalysts are certain unsupported Group IA or IIA metal salt-promoted Fe—Co spinels. The patent reports certain high surface area (100-200 m2/g) Fe—Co spinels prepared in an acid aqueous solution containing alpha-hydroxy carboxylic acids. The iron to cobalt atomic ratio of the metals in the spinel is reported to be 4:1 or above. The catalysts are reported to be useful in slurry processes for selectively producing high amount of C2 to C20 alpha-olefin materials.
U.S. Pat. No. 4,151,190 reports a catalyst comprising at least one of a sulfide, oxide, or metal of Mo, W, Re, Ru, Ni, or Pt, at least one of a hydroxide, oxide, or salt of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, or Th, and a support, used for conversion of synthesis gas with an H2:CO ratio of 0.25-4.0, preferably 0.5-1.5, to C2-C4 hydrocarbons at a pressure of 15-2000 psia and a temperature of 250-500° C. at a typical gas hourly space velocity of 300 v/hr/v. This catalyst is reported regenerated by contacting it with hydrogen gas at 500-600° C. for 16 hours.
Moser et al. (Moser, W. R., Lennhoff, J. D., Cnossen, J. E., Fraska, K., Schoonover J. W., and Rozak, J. R. (1996) in "Advanced Catalysts and Nanostructured Materials; Modern Synthetic Methods" (Moser, ed.) Academic, San Diego, Calif., p. 540) reports the synthesis and testing of certain perovskite compositions by spray pyrolysis or high temperature aerosol decomposition (HTAD). The materials synthesized have the general stoichiometry: La(1-x)MxFeO3, where M is Ca2+ or Sr2+; La(1-x)LnxFeO3, where Ln is certain unidentified lanthanide ions; and La(1-x)Srx CoO3 where in each case x ranges between 0.0 to 1.0, as well as certain unidentified perkovskites in the LaCoO3 and LaFeO3 series "having two additional ions modifying both the A- and B-sites simultaneously." All of the perovskites tested were reported to be catalytically activity for F-T synthesis. However little detail of the catalytic activity of the catalysts as a function of structure was provided. CO consumption rate (normalized to unit surface area) for the La(1-x)CaxFeO3 series as a function x from 0.0 to 0.8 was illustrated in FIG. 3 of the reference to increase with increasing x value (i.e. increasing Ca content). It was also reported that the surface areas of the perovskites could be varied from 10 to 50 m2/g and that the perovskites prepared had little to no micropore structure. Perovskites prepared by classical synthesis by high temperature fusion techniques were reported to result in materials having much lower surface areas (0.1-1 m2/g) compared to HTAD materials and in materials in which the perovskite could not be obtained free from separate phases of the component metal oxides.
Goldwasser et al. J. Mol. Catalysis A: Chemical 193(2003) 227-236 report a series of iron perovskite oxide materials containing K or Mn or both as precursors for conversion of syngas to low molecular weight alkenes the having the general composition:La1-xKxMnyFe1-yO3where 0≦x, y≦0.2, specifically La Fe O3, La0.9K0.1FeO2.9, LaO0.8K0.2FeO2.9, LaFe0.8Mn0.2O3, and La0.9K0.1Fe0.9Mn0.1O2.9. The active catalysts are prepared by reduction of the raw catalyst. Prior to assessing catalytic activity the perovskite oxides were subjected to reduction at 450° C. in a flow of H2 (30 mL/min/g catalyst) for 16 h followed by exposure to CO (10 mL/min/g catalyst) for 8 h at 150° C. and for carburated catalysts at 350° C. for 14 h. The activity of the perovskite-based catalysts was reported to seem to be directly related to the formation of Hatgg carbides. For conversion of a mixture where H2/CO=2, SCO2(%) (CO2 selectivity) of 30 or more was observed.


A catadioptric projection optical system for forming plural intermediate images of a first object and for imaging the image of the first object onto a second object, said catadioptric projection optical system includes at least one concave mirror, a first deflective reflector, and a second deflective reflector, wherein a light reflected by the first deflective reflector is directly led to the second deflective reflector.

The present invention relates generally to a projection optical system, and more particularly to a catadioptric projection optical system that projects an object, such as a single crystal substrate and a glass plate for a liquid crystal display ("LCD"), using a mirror. The present invention is suitable, for example, an immersion exposure apparatus (an immersion lithography exposure system) for exposing the object through a liquid between the projection optical system and the object.
The photolithography technology for manufacturing fine semiconductor devices, such as semiconductor memory and logic circuits, has conventionally employed a reduction projection exposure apparatus that uses a projection optical system to project and transfer a circuit pattern of a reticle (or mask) onto a wafer, etc. A more highly integrated and finer semiconductor device (circuit pattern) requires a projection optical system for a better specification and performance. Generally, a shorter wavelength of the exposure light and a higher numerical aperture ("NA") are effective to improve the resolution. Recently, an optical system with an NA of 1 or higher that utilizes an immersion optical system that fills a space with liquid between a final glass surface (in other words, the lens closet to the wafer) of the projection optical system and the wafer has been proposed, and a higher NA scheme is in progress.
For the exposure light with a short wavelength such as an ArF excimer laser (with a wavelength of approximately 193 nm) and a F2 laser (with a wavelength of approximately 157 nm) for higher resolution, lens materials are limited to quartz and calcium fluoride for reduced transmittance. An optical system that includes only lenses (refracting element) uses, generally, quartz and calcium fluoride for the exposure wavelength of 193 nm for instance. However, quartz and calcium fluoride possess similar dispersive powers, and have difficulties in correcting the chromatic aberration, especially, for the optical system that has a very higher NA as in the immersion optical system. Moreover, a lens diameter increases as the NA becomes higher, and causes the increased apparatus cost.
Then, various proposals that use a mirror (reflecting element) for an optical system have been made to solve the disadvantageous reduced transmittance, difficult corrections to the chromatic aberration and large aperture of the lens. For example, a catadioptric projection optical system that combines a mirror with a lens has been disclosed. See, for example, Japanese Patent Applications, Publication Nos. 2004-205698, 8-62502 and 2003-307679.
A projection optical system that includes a mirror for a shorter exposure wavelength and a higher NA needs to correct the chromatic aberration corrections, maintain a large enough imaging area on an image surface, and have latitude for a higher NA. Especially, when the NA of higher than about 1.1 dramatically increases an object-to-image distance (in other words, a distance between a reticle and a wafer), and an effective diameter of lens inevitably enlarging the optical system and increasing the apparatus cost.
The optical system disclosed in Japanese Patent Application, Publication No. 2004-205698 propose a twice-imaging catadioptric optical system for forming an intermediate image once. The optical system includes a first imaging optical system that has a reciprocating optical system (double-pass optical system) which includes concave mirror and forms an intermediate image of a first object (e.g., a reticle), and a second imaging optical system that forms the intermediate image onto a surface of a second object (e.g., a wafer). Moreover, the optical system arranges a first plane mirror near the intermediate image for deflecting an optical axis and light. The deflected optical axis from the first plane mirror is made approximately parallel to a reticle stage and is deflected once again by a second plane mirror, and images onto the second object. The optical system disclosed in Japanese Patent Application, Publication No. 2004-205698 has the above structure, and inevitably arrange the first object (e.g., a reticle), a lens, plane mirror and the deflected light close to one another. Therefore, the optical system creates a problem of interference between the first object (e.g., a reticle) surface or the reticle stage and the lens or the plane mirror or an insufficient space. The optical system in FIG. 5 of Japanese Patent Application, Publication No. 2004-205698 is an immersion optical system with an NA of 1.05. However, a maximum effective diameter is over φ300, and if NA achieves higher NA such as 1.2 or higher, the effective diameter is remarkably enlarged.
The optical system in FIGS. 7 and 9 of Japanese Patent Application, Publication No. 8-62502 is a catadioptric optical system with an NA from 0.45 to 0.5 for forming an image three times or an intermediate image twice. The optical system includes a first imaging optical system that forms a first intermediate image of a first object (e.g., a reticle), a second imaging optical system that includes a concave mirror and forms a second intermediate image from the first intermediate image, and a third imaging optical system that images the second intermediate image onto a second object (e.g., a wafer) surface. The second imaging optical system includes concave mirrors as a reciprocating optical system. In this optical system, the first object (e.g., a reticle) and the second object (e.g., a wafer) are not arranged in parallel. The imaging performance improves in a scanning exposure, and a stability performance can be maintained when the first and second objects are arranged in parallel to each other and perpendicular to the gravity. Therefore, it is undesirable for an exposure apparatus that has an optical system with a higher NA by the immersion etc. to arrange the first object (e.g., a reticle) and second object (e.g., a wafer) in not parallel. This optical system needs another plane mirror to arrange the first object (e.g., a reticle) and second object (e.g., a wafer) in parallel. In that case, as described in Japanese Patent Application, Publication No. 8-62502, if a mirror is arranged near the first intermediate image, the arrangement is the same as the optical system in FIGS. 4 and 6 of Japanese Patent Application, Publication No. 20003-307679 described later. If an optical axis of the lens (optical element) having a refractive power is not along the gravity direction, the imaging performance deteriorates by self-weight deformations and influences of retainer. Therefore, preferably, the optical element having a refractive power with the optical axis that is not along the gravity direction does not exist as much as possible. However, the optical system in FIGS. 7 and 9 of Japanese Patent Application, Publication No. 8-62502 includes plural optical element with the optical axis that is not along the gravity direction.
The optical system with an NA of almost 0.85 in FIGS. 4 and 6 of Japanese Patent Application, Publication No. 2003-307679 arranges a plane mirror (reflection block) near the first and second intermediate images, and aligns optical axes of the first and third imaging optical systems with each other. Thus, the first object (e.g., a reticle) and the second object (e.g., a wafer) are arranged in parallel. However, such an optical system becomes considerably large when the NA becomes 1 or higher as in the immersion optical system, especially, about 1.1 or higher. Since the first imaging optical system from the first object (e.g., a reticle) to the vicinity of the plane mirror and the third imaging optical system from the vicinity of the plane mirror to the second object (e.g., a wafer) are arranged on a straight line of the optical axis, a sum of the object-to-image distance of the first imaging optical system and the object-to-image distance of the third imaging optical system becomes the the object-to-image distance (the distance between the reticle and the wafer) of the entire optical system. Due to the strong refractive power of each lens necessary to maintain the size of the optical system with a higher NA, the aberration correction becomes difficult. Moreover, because of a small reduction magnification in the first imaging optical system, the first intermediate image enlarges the NA of the first intermediate image for an object-side NA in the first object (e.g., a reticle) by the reduction magnification. As a result, both an incident angle range and the maximum incident angle upon the plane mirror increase, and a higher NA scheme as in the immersion etc. encounters a serious problem. In other words, both the incident angle range and the maximum incident angle upon the plane mirror considerably increase due to the NA of 1 or higher, and the imaging performance inevitably deteriorates by the influence of a deteriorated property of the plane mirror etc. Because the plane mirror is also arranged near the second intermediate image, this is true of the second intermediate image. Moreover, as the above-mentioned, optical axes of the concave mirror and the negative lens in the second imaging optical system are perpendicular to the gravity direction, and it is not desirable structure to improve a final performance to a limit.

Catadioptric projection optical system and exposure apparatus having the same