Methods and apparatus for cementing a pipe in a well bore penetrating one or more subterranean gas-containing formations without incurring substantial gas inflow are provided. The methods basically comprise the steps of placing a hydraulic cement slurry in the annulus between the pipe and the well bore, and moving the pipe during the transition period of the slurry. The moving of the pipe maintains the hydrostatic pressure exerted by the slurry on the gas-containing formations and prevents gas flow into the slurry and the well bore. The movement of the pipe is stopped when the slurry develops sufficient gel strength to substantially block gas flow through the well bore.

1. Field of the Invention
The present invention relates to methods and apparatus for carrying out primary cementing operations in a well bore without incurring substantial gas inflow.
2. Description of the Prior Art
In the primary cementing of wells, a pipe disposed in a well bore, e.g., casing, is cemented therein whereby the pipe is bonded to the walls of the well bore. The bonding serves to maintain the pipe in place and to prevent subterranean formation fluids from communicating between zones or to the surface by way of the annulus between the well bore and the pipe. Typically, primary cementing is carried out by pumping a cement slurry downwardly through the pipe to the bottom thereof and then upwardly into the annulus. The cement slurry is displaced out of the pipe and into the annulus by a displacement fluid and upon being placed in the annulus, the cement slurry is allowed to set into a hard impermeable mass therein.
When one or more of the subterranean formations or zones penetrated by the well bore contain pressurized gas, a problem often encountered involves the flow of gas into the cement slurry and into the well bore prior to when the cement slurry sets. Such gas can flow to the surface, create communication between producing or other subterranean formations or zones and can, when in high enough volume, create a blow out shortly after the primary cementing operation is complete.
The occurrence of gas flow in a cemented pipe-well bore annulus relates to the inability of the cement slurry to transmit hydrostatic pressure during the transition period in which the slurry converts from a true fluid to a partially self supporting semisolid as a result of the development of static gel strength. Static gel strength can be defined as internal rigidity in the matrix of the cement that resists a force placed upon it. The development of static gel strength starts immediately after placement of the cement slurry in the annulus and continues to increase as the cement hydrates or sets. At a point before initial set, the cement slurry develops a static gel strength high enough to prevent pressurized gas from moving through it.
When the cement slurry is initially placed in the annulus, it exerts hydrostatic pressure on gas-containing formations penetrated by the well bore whereby gas flow into the cement slurry and into the well bore is prevented. However, after the cement slurry becomes partially self-supporting, the ongoing hydration reactions in the slurry and fluid losses therefrom cause volume reductions to take place in the slurry which in turn causes the hydrostatic pressure exerted by the slurry to be reduced. When the hydrostatic pressure is reduced below the pressure of the gas, gas flow through the slurry contained in the well bore takes place.
A number of methods and special hydraulic cement compositions have been developed and used to minimize gas inflow during primary cementing. Examples include multiple stage cementing methods, maintaining a back pressure on the annulus and/or including special additives in the cement composition such as latexes, special fluid loss prevention additives, in situ gas generating additives, etc. While the prior methods and cement compositions have achieved varying degrees of success, they are relatively expensive and problems caused by gas inflow still often result.
Thus, there is a need for improved methods and apparatus for carrying out primary cementing operations in wells whereby expensive cement slurry additives are not required and gas flow into the cement slurry and well bore is substantially prevented.


A startup control method of a BLDC motor is disclosed. The method can control the BLDC motor to prevent the generation of a transient current such that the vibration of the BLDC motor can be reduced at the startup stage and perform a stable conversion into a sensorless operation mode such that the startup failure rate of the BLDC motor can be reduced. The startup control method includes commutating a current applied to stator windings according to a rotor position. The method of operating the BLDC motor includes a rotor position that is forcibly aligned and so that phase commutation is performed, a back-electromotive force (back-emf) is detected from a lead voltage of a phase of a voltage which is not applied thereto after performing phase commutation and a determination is performed as to whether the detected back-emf is in a rising interval. The lead voltage of the phase of the voltage which is not applied thereto is integrated, such that if the back-emf is in a rising interval and if an instance that the integration result is greater than a predetermined value a phase commutation time point is set and conversion into a sensorless operation mode is performed if the back-emf detected from the lead voltage is in a stable interval, based on a frequency of the voltage applied to the stator winding.

1. Field of the Invention
The present invention relates to a senseless startup control technique of a brushless direct current motor (hereinafter referred to as BLDC motor), and, more particularly, to a method that is capable of controlling a BLDC motor to prevent the generation of transient current in its startup stage.
2. Description of the Related Art
Generally, a BLDC motor includes a stator as an armature inducing electromotive force (emf) by a current-carrying coil thereof, and a rotor as a permanent magnet having N-S poles, in which the rotor is rotated with respect to the stator. It is necessary to form continuous rotating magnetic field of the BLDC motor such that the BLDC motor can be successively operated. Phase commutation of current flowing through each of windings is performed at a proper time to form a continuous rotating magnetic field, which can be achieved as a rotor position is correctly recognized. Here, the term "commutation" means to change the direction of current flowing through the windings of the stator such that the rotor can be rotated with respect to the stator.
To smoothly operate the BLDC motor, the rotor position is accurately consistent with the commutation time point of the phase current, which requires a device for detecting the rotor position. Although the device employs a position sensor, such as a Hall sensor, a Resolver sensor, and an encoder, the position sensor causes problems such as an increase of manufacturing cost of the BLDC motor, complication of driving circuits, etc. To resolve such problems, a method for detecting rotor position using electric circuits is researched.
Thus, an electric circuit for detecting rotor position is developed using back-emf of a BLDC motor. As such, the BLDC motor is operated by the rotor position that is detected by an electric circuit, instead of a position sensor. Hence, it said that "the motor is operated in a sensorless operation mode."
Before a BLDC motor is operated in a senseless operation mode, it must pass through a startup stage, which will be described below with reference to FIGS. 1 and 2.
In FIG. 1, current is supplied to two phases of the BLDC motor (for example, if the BLDC motor has three phases) such that a rotor is forcibly aligned as illustrated in operation 1. At operation 2, after completing the alignment of the rotor, the amplitude and frequency of the voltage applied to the BLDC motor are varied such that the rotation speed of the rotor of the BLDC motor can be forcibly accelerated to reach a predetermined speed, as shown in FIG. 2, in operation 2. At operation 3, when the rotation speed of the rotor reaches the predetermined speed such that back-emf can be detected from the stator winding of the BLDC motor, the voltage supplied to the BLDC motor is controlled such that magnetic field phases of the rotor and the stator are adjusted. After that, at operation 4, the present operation mode of the BLDC motor is converted into a sensorless operation mode such that phase commutation and speed control of the BLDC motor are performed to run the BLDC motor, based on position information of the rotor, in which the position information is indirectly detected from back-emf information of the BLDC motor.
However, the conventional sensorless operation control method of the BLDC motor requires position information of the rotor to drive the BLDC motor. If a voltage is supplied to a stator winding in a state wherein position information of the rotor is not recognized, a transient current is generated. The transient current causes the generation of relatively large torque pulsation and the demagnetization of a permanent magnet of the rotor.
Also, since a voltage with a specific frequency pattern is applied to the BLDC motor regardless of the substantial position of the rotor before the BLDC motor is converted into the sensorless operation mode, the transient current causes the generation of torque pulsation and the demagnetization of a permanent magnet. Furthermore, the excessive torque pulsation may cause failure of conversion of the sensorless operation mode.
To resolve the above mentioned problems, U.S. Pat. No. 5,859,520 discloses that a lead voltage of the BLDC motor is detected to be compared with a voltage of '0,' and a zero crossing point (ZCP) of back-emf thereof is detected. After that, the BLDC motor is delayed by a time corresponding to one-half of the average ZCP detection time of the back-emf to perform phase commutation.
According to a method disclosed in U.S. Pat. No. 5,859,520, only the switching elements of the inverter are controlled by a PWM, and a lead voltage of a phase to which a voltage is not applied is compared with a voltage of '0' to detect a ZCP of back-emf. After that, the BLDC motor is delayed by a time corresponding to one-half of the average detection time point of the ZCP of the back-emf to perform phase commutation. Similar to the descriptions of FIGS. 1 and 2, the BLDC motor must be synchronously accelerated until a ZCP of the back-emf can be detected.
However, the conventional method has disadvantages in that, since the BLDC motor must be synchronously accelerated until the ZCP of the back-emf can be detected, it has a high possibility that a transient current can be generated. Also, the conventional method has drawbacks in that, when the BLDC motor is delayed by a time corresponding to one-half of the average detection time point of a ZCP of a back-emf to perform phase commutation, a system generating large load variation at a very low speed, such as a compressor, cannot perform phase commutation at a correct phase commutation time point. Therefore, in the conventional methods, there is a high possibility that a transient current can be generated.
Furthermore, IEEE ("Four-quadrant sensorless brushless ECM drive", 10–15 Mar., 1991) discloses a startup control method of a senseless BLDC motor that is capable of integrating back-emf, comparing the integration result with a specific voltage level, and then performing phase commutation based on the comparison. However, since the conventional methods must synchronously accelerate the BLDC motor until a back-emf can be detected, there is a high possibility that a transient current can be generated at a startup of the BLDC motor.

Startup control method of brushless DC motor


A nuclear camera acquires projections which are iteratively reconstructed by a reconstruction processor into an motion-artifacted image and stored in an image memory. The motion-artifacted image is forward-projected by a forward-projector to create forward-projections which are compensated for image degrading factors, such as resolution recovery, scatter and attenuation, and are compared with the acquired projections by a comparing unit to generate a motion-correction. A motion compensator operates on the acquired projections with the motion-correction to generate a motion-corrected projection data set in which each of the projections is in a common motion state. The motion-corrected projections are reconstructed into a motion-corrected image.

The present application pertains to the diagnostic imaging arts. It finds particular application in conjunction with single photon emission computed tomography (SPECT) and will be described with particular reference thereto. It is to be appreciated, however, that it may also be applicable to other types of nuclear imaging, as well as other types of diagnostic imaging.
In SPECT imaging, a patient is injected with a radioactive tracer which breaks down to emit gamma rays of a characteristic energy. One or more SPECT detector heads are positioned adjacent the patient and rotated to a plurality of angular orientations. The data collected at each angular orientation represents projection data depicting the distribution of the radioactive tracer in the patient. These projections are then reconstructed into a three-dimensional diagnostic image.
A SPECT acquisition typically takes about 10 minutes or more to complete. During that time, the patient may move. Further, internal organs may also move during the imaging time. This motion, of course, causes motion-artifacts.
A commonly-used technique for motion-correction is described in U.S. Pat. No. 5,552,605. The projection data is first reconstructed into an image-artifacted three-dimensional image. The three-dimensional image is then forward-projected along each of the projection directions to generate a series of re-projections. The region of interest in each original projection and re-projection corresponding to the same angular orientation are compared and the original projections are shifted into alignment with the corresponding re-projection. The shifted original projections are reconstructed into a motion-correction 3D volume image. This process may be iteratively repeated to refine the motion-correction.
Although the technique of U.S. Pat. No. 5,552,605 has been used commercially for many years to generate motion-corrected SPECT images, there is room for improvement. Particularly, due to other degrading factors such as attenuation, scatter, system blurring, the shift amount even with the best match of the re-projection and the actually measured projection may not reflect the actual motion amount. In some cases, a significant artificial motion may be introduced which may compromise motion-correction success and accuracy.
The present application improves the motion-correction and accuracy by recognizing image degrading factors such as attenuation, scatter, and system resolution and considering them during iterative image reconstruction and motion-correction.


A parking time display device is provided in a car to display the time during which the car is parked. The parking time display device includes a sensor for detecting a stopping or parking condition of the car, a counter for counting time, a control circuit for controlling the counter, and a display. The display is arranged at a portion of the car which is visible from outside of the car.

The present invention relates to a parking time display device installed in a vehicle for displaying a parking time of the vehicle.
Among various urban problems, unlawful parking is a serious one; unlawful parking often causes heavy traffic jams, and is very difficult to strictly control. Usually, it is deemed unlawful to stop or park a car at a place not admitted over a predetermined time. Accordingly, it is important to know how long the car has been stopped or parked at that place in order to control such unlawful parkings.
However, one can not know usually whether or not a car has been stopped or parked illegally at a glance, unless the parking spot is provided with a parking meter. Although the parking meter can warn when a predetermined parking time has elapsed, it does not serve as an adequate monitor of unlawful parking, since a payment of an additional parking fee cancels such an unlawful state alleged.

Parking time display device equipped in a vehicle with a motor


A release tool is provided to aid in the unlocking of extending towing arms. The tool is adapted to fit a tow bar assembly that has a telescoping towing arm which is locked in an extended position by a slideable collar. The collar is moveable between a locked position and a released position. When in the locked position, the collar holds catches in engagement with legs of the towing arm to hold the legs fixed relative to each other. When in the released position, the legs are free to telescope relative to each other. Stress can build-up in the towing arms making it difficult to move the collar from the locked position to the released position. The release tool of the present invention provides a mechanical advantage to aid in the movement of the collar from the locked position to the released position. A cam surface on the tool engages the collar and moves it from the locked position to the released position as a handle is rotated about a fulcrum means.

The invention relates generally to hitching members for connecting a towed vehicle to a towing vehicle, and more particularly to a tool for use in moving a collar on a telescoping towing arm from a locked position to a released position to allow the towing arm to extend and collapse telescopically.
Tow bar assemblies for use as hitching members are common in the art. These assemblies generally use two towing arms which are coupled between a towing vehicle and a towed vehicle. It is desirable to be able to fold the tow bar assembly for storage. To this end, tow bar assemblies with collapsible arms have been suggested. This allows the towing arms to fit in a smaller space when not in use. Therefore, these towing arms are generally movable between a collapsed storage position, and an extended towing position. A preferred design for the towing arms uses an inner and an outer telescoping leg. They must be provided with some means for locking the arms in the extended position to hold the towed vehicle at a substantially constant distance from the towing vehicle during towing.
It has been shown in the prior art to use a slideable locking collar on telescoping towing arms in a tow bar assembly, as for example in U.S. Pat. No. 5,356,166, and in an application filed concurrently with this application, in order to accomplish locking the arms in place. This collar is moveable between a locked position and a released position. When in the locked position, the collar holds a catch in place through a hole in the outer telescoping leg and against a groove in the inner telescoping leg, thereby preventing the legs from telescoping relative to each other. Tension or compression can develop in the towing arms, thereby tending to force the catch outward, away from the inner leg. This presses the catch against the collar, making it difficult to move the collar from the locked position to the released position in order to collapse the legs.
The difficulties encountered in the prior art and discussed above are substantially eliminated by the present invention.

Release tool for telescoping towing arms


An uninterruptible power supply (UPS) includes a power conversion circuit and a relay. The relay is configured to couple and decouple a power source to and from an input of the power conversion circuit. The control circuit is operative to apply a coil current to the relay to sense the coil current and to detect an operational failure of the relay from the sensed coil current. Related methods of operating such UPSs are also provided.

The present invention relates to a power supply apparatus and methods of operation thereof, and more particularly, to uninterruptible power supplies (UPSs) and methods of operation thereof.
UPSs are commonly used to provide conditioned and/or auxiliary power to electronic equipment that provides critical functions, such as computer systems, telecommunications systems and medical equipment. Typically, UPSs can provide AC power from a backup source, such as a battery, generator or fuel cell, in the event that a utility power supply fails or becomes degraded.
UPSs may be coupled to and decoupled from one or more power sources using, for example, a relay. In particular, UPSs are often coupled to more than one source of power. For example, a UPS may have a primary source of power such as a utility, and a secondary source of power, such as battery or generator. The UPS may be coupled to the primary source of power and the secondary source of power using first and second relays, respectively. If one of the relays welds closed, the UPS may connect the sources together, which may damage the sources and/or interconnecting wiring.
Methods of determining a state of a relay have been developed to address this issue. For example, a light emitting diode (LED) may be placed across the relay contact to provide a visual indication as to whether the relay is open or closed. However, these types of sensors may not be reliable and may provide a false indication.

Devices and methods for detecting operational failures of relays


An optical stop unit includes plural light blocking plates, and a cam mechanism for driving the plural light blocking plates to vary an aperture diameter, the cam mechanism including a cam follower and a cam groove, wherein the cam follower and cam groove have mutually facing surfaces, through which the cam follower and cam groove contact each other, and at least one of which surfaces has a curved section that is substantially perpendicular to a plane formed by the plural light blocking plates.

The present invention relates generally to exposure apparatuses, and more particularly to an exposure apparatus that is used to expose an object, such as a single crystal plate for a semiconductor wafer, a glass plate for a liquid crystal display ("LCD"), and the like, an optical stop unit used for such an exposure apparatus, a device fabrication method using the exposed object, and a device fabricated from the exposed object. The present invention is suitable, for example, for an exposure apparatus that exposes a single crystal plate for a semiconductor wafer in a step-and-scan, scan, or step-and-repeat projection manner in a photolithography process.
The "step-and-scan" manner, as used herein, is one mode of exposure method which exposes a pattern on a mask onto a wafer by continuously scanning the wafer relative to the mask or reticle (these terms are used interchangeably in this application) and moving, after a shot of exposure, the wafer stepwise to the next exposure area to be shot. The "scan" manner is another mode of exposure method which uses a projection optical system to project part of a mask pattern onto a wafer, and exposes the entire mask pattern to the wafer by relatively and synchronously scanning the mask and the object relative to the projection optical system. The "step-and-repeat" manner is still another mode of exposure method which moves a wafer stepwise to an exposure area for the next shot every shot of cell projection onto the wafer.
Along with recent demands on smaller and lower profile electronic devices, fine semiconductor devices to be mounted onto these electronic devices have been increasingly demanded. For example, a design rule for a pattern on a mask attempts a line and space (L & S) of 130 nm on a mass production line, which will be predictably increasingly smaller in the future. L & S denotes an image projected to a wafer in exposure with equal line and space widths, and serves as an index of exposure resolution. The exposure has three important factors including resolution, overlay accuracy, and throughput. The resolution is the minimum size for a precise pattern transfer. The overlay accuracy is a precision with which to overlay multiple patterns over an object to be exposed. The throughput is the number of sheets exposed per unit of time.
There are two basic exposure methods including a full-size transfer method and a projection method. The full-size transfer includes a contact method that brings a mask into close contact with an object to be exposed, and a proximity method that slightly spaces them from each other. Although the contact method may provide higher resolution, dusts and silicon fragments enter under a mask in a compressed state, and damage the mask, causing the exposed object to be flawed and defective. The proximity method ameliorates such problems, but still possibly damages the mask if a distance between the mask and the object to be exposed becomes shorter than the maximum size of a dust particle.
A projection method has been suggested accordingly which farther spaces the mask from the object to be exposed. Among projection modes, a scan projection exposure apparatus has been the recent trend for the improved resolution and expanded exposure area, which exposes the entire mask pattern onto the wafer by exposing part of the mask, synchronizing the mask and wafer, and scanning the wafer continuously or intermittently.
A projection exposure apparatus generally includes an illumination optical system that uses light emitted from a light source to illuminate a mask, and a projection optical system located between the mask and the object to be exposed. For a uniform illumination area, the illumination optical system introduces the light from a light source to a light integrator, such as a fly-eye lens, which includes a plurality of rod lenses, and uses a condenser lens to Kohler-illuminate the mask surface with an exit plane of the light integrator as a secondary light source surface.
The following equation provides the resolution R of the projection exposure apparatus where λ is a light-source wavelength and NA is a numerical aperture of the projection optical system:
                    R        =                              k            1                    ·                      λ                          N                                                                                A                                                          (        1        )
The shorter the wavelength becomes and the higher the NA increases, the better the resolution thus becomes. For improved resolution, an exposure apparatus has recently been put to practical use that has a projection optical system with a higher NA, e.g., NA=0.70 or higher.
A focus range that maintains desired imaging performance is called a depth of focus ("DOF"), which is given by the following equation:
                    DOF        =                              k            2                    ·                      λ                          N                                                                                A                2                                                                        (        2        )
The shorter the wavelength becomes and the higher the NA increases, the smaller the DOF thus becomes. A small DOF would make difficult focusing as well as requiring a flatter plate and a more accurate focusing. Therefore, a large DOF is basically desirable.
An actual process calculates a condition of an optimal NA to improve the resolution while securing the DOF. A projection optical system thus usually includes an optical stop unit for continuously varying NA, selecting and using the NA. For example, as disclosed in Japanese Laid-Open Patent Application 7-301845, a conventional NA-adjusting optical stop unit uses an iris stop unit that includes overlaying plural light blocking plates, and varies a diameter of an aperture by sliding and turning each light blocking plate.
For an enlarged chip size of a semiconductor device, a step-and-repeat exposure apparatus (stepper) is shifted to a step-and-scan exposure apparatus (scanner). The step-and-scan manner uses a slit-shaped exposure field to maximize the performance of a certain boundary in the projection optical system and expand an exposure area.
A large exposure area and an increased NA would enlarge an optical element (such as a lens's effective diameter of about Φ 200˜300 mm), and an aperture diameter of an optical stop unit included in an optical system. A large aperture of a stop diameter would enlarge a light blocking plate that makes up an iris stop unit and increase the number of light blocking plates. Since the light blocking plate is adapted to be as thin as possible so that it can shield light having various angles, a larger light blocking plate easily deteriorates its flatness. The deteriorated flatness of the light blocking plate would increase the load to a cam that drives the light blocking plate, causing the cam idle or dead, and uncontrollability of driving. In particular, an optical stop unit is usually housed in a lens barrel in a projection optical system inaccessibly, and any failure and malfunction in the optical stop unit would result in an extensive repair in the exposure apparatus, consequently lowering the economical efficiency of the exposure apparatus, and the throughput of the exposure due to the repair time.

Optical stop apparatus and exposure apparatus having the same


An underground longwall mining method includes drilling a main shaft and an auxiliary shaft from a ground to a coal bed and exploiting in the coal bed first and second connection laneways. The first connection laneway is in communication with the main shaft, and the second connection laneway is in communication with the auxiliary shaft. The method further includes communicating the first and second connection laneways, and using a communication part between the first connection laneway and the second connection laneway as a first open-off cut; and by using a direction of the first open-off cut further away from the connecting line connecting the main shaft and the auxiliary shaft as a first direction, and exploiting by cutting a coal wall in the first direction using a coal mining machine.

Underground coal exploitation usually requires to excavate from the ground to underground a series of shafts and laneways, including a main shaft, an auxiliary shaft, an exploiting laneway, a preparatory laneway, a stopping laneway and so on. In order to protect those laneways, during the mining, it is further required to leave a large quantity of laneway protecting coal pillars adjacent to the laneways, to prevent the laneways from being destroyed by mining actions and roof motions. Such a mining approach has been developed in China for decades, and currently has become the most extensively applied exploiting mode. It has made a huge contribution to the coal exploitation of China, but has many problems:
(1) The laneway protecting coal pillars left adjacent to the shaft station, the exploiting laneway, the preparatory laneway and the stopping laneway causes a serious resource waste and a serious harm to the environment.
(2) The large laneway excavation amount causes a high production cost. The underground exploitation usually requires to excavate a large quantity of laneways, including an exploiting laneway, a preparatory laneway, a stopping laneway and so on.
(3) Laneway accidents frequently happen. According to statistics, among coal-mine accidents, laneway accidents account for 91%, wherein those in the working-face stopping laneways account for approximately 90% of the laneway accidents.
(4) The shaft construction requires a long period and a huge investment. In order to enable each of the stopping working faces to normally connect, one coal mine is required to be provided with a plurality of excavation working faces, which needs a lot of workers, a high excavation amount, a long excavation time and a high excavation cost, and the alternation between the coal mining and the excavation is tense. The tremendous workload of the excavation causes an extremely long time for the early-stage preparation of coal production, increases the cost of coal production, and wastes a large amount of time and money.
In conclusion, the conventional techniques of coal mining have the problems of a large laneway excavation amount, a long excavation time, a high excavation cost and frequent laneway accidents, and the coal-pillar leaving causes a huge waste of the coal resource.

Beijing Zhongkuang Innovation Alliance Energy Environment Science Academy


Process for producing acrylonitrile or methacrylonitrile from propane or isobutane by ammoxidation at a temperature in the range of from 380 to 500.degree. C. in a fluidized-bed reactor containing a catalyst composition preheated to a temperature of not lower than 300.degree. C. and lower than the ammoxidation reaction temperature, the catalyst composition comprising a carrier having supported thereon an oxide catalyst comprising a compound oxide of molybdenum, vanadium, niobium and at least one element selected from tellurium and antimony, wherein the ammoxidation of propane or isobutane is preceded by a specific temperature elevation operation in which the catalyst temperature in the reactor is elevated, while supplying into the fluidized-bed reactor a molecular oxygen-containing gas together with a combustible gas capable of combustion by reaction with the molecular oxygen in the presence of said catalyst composition, until the temperature of the catalyst composition reaches said ammoxidation reaction temperature. The process of the present invention is advantageous in that the temperature elevation of the catalyst can be performed without suffering a deterioration of the catalytic activity during the temperature elevation, thereby allowing the catalyst to fully exhibit its performance.

1. Field of the Invention
The present invention relates to a process for producing acrylonitrile or methacrylonitrile from propane or isobutane by ammoxidation. More particularly, the present invention is concerned with a process for producing acrylonitrile or methacrylonitrile from propane or isobutane by ammoxidation at a temperature in the range of from 380 to 500.degree. C. (ammoxidation reaction temperature) in a fluidized-bed reactor containing a catalyst composition preheated to a temperature of not lower than 300.degree. C. and lower than the ammoxidation reaction temperature, the catalyst composition comprising a carrier having supported thereon an oxide catalyst comprising a compound oxide of molybdenum, vanadium, niobium and at least one element selected from the group consisting of tellurium and antimony, wherein the ammoxidation of propane or isobutane at the ammoxidation reaction temperature is preceded by a specific temperature elevation operation in which the temperature of the preheated catalyst composition in the fluidized-bed reactor is elevated, while supplying into the fluidized-bed reactor a molecular oxygen-containing gas together with a combustible gas capable of combustion by reaction with the molecular oxygen in the presence of the catalyst composition, until the temperature of the catalyst composition reaches the ammoxidation reaction temperature. By virtue of the above-mentioned specific temperature elevation operation using both a molecular oxygen-containing gas and a combustible gas when the temperature of the catalyst composition is 300.degree. C. or higher, the process of the present invention is advantageous in that the temperature elevation of a catalyst comprising a compound oxide of molybdenum, vanadium, niobium and at least one element selected from tellurium and antimony can be performed without suffering a deterioration of the catalytic activity during the temperature elevation of the catalyst, thereby allowing the catalyst to fully exhibit its inherent performance.
2. Prior art
It has been well known to produce an unsaturated nitrile, such as acrylonitrile or methacrylonitrile, by ammoxidation of an olefin, such as propylene or isobutene, namely, by reacting an olefin with ammonia and molecular oxygen.
On the other hand, from the viewpoint of reducing the cost for raw materials, attention has been attracted to a process for producing an unsaturated nitrile (such as acrylonitrile or methacrylonitrile) from an alkane (such as propane and isobutane), which is available at low cost as compared to an alkene, by ammoxidation in the presence of a catalyst, i.e., by reacting an alkane with ammonia and molecular oxygen in the presence of a catalyst. Further, a number of proposals have also been made with respect to catalysts for use in the ammoxidation of an alkane.
For example, as a catalyst for use in producing acrylonitrile by ammoxidation of propane, there is known an oxide catalyst containing molybdenum, vanadium, tellurium and niobium. Such a catalyst and a method for producing the catalyst are disclosed in each of Japanese Patent Publication No. 2608768 (published in 1997)(corresponding to U.S. Pat. No. 5,049,692), Unexamined Japanese Patent Application Laid-Open Specification No. 5-208136 (corresponding to U.S. Pat. No. 5,281,745) and Unexamined Japanese Patent Application Laid-Open Specification No. 6-285372 (corresponding to U.S. Pat. No. 5,422,328). Further, Unexamined Japanese Patent Application Laid-Open Specification No. 9-157241 (corresponding to European Patent No. 767,164) discloses an oxide catalyst containing molybdenum, vanadium, antimony and niobium as a catalyst for use in producing acrylonitrile by ammoxidation of propane. These prior art documents have a description concerning ammoxidation reaction conditions employed in the evaluation of the performance of such catalyst. However, with respect to the manner of elevating the temperature of the catalyst before starting the ammoxidation reaction of propane, no description is found in these prior art documents.
Unexamined Japanese Patent Application Laid-Open Specification No. 10-57813 discloses a process for producing acrylic acid by oxidation of propane, using a catalyst containing molybdenum, vanadium and at least one element selected from tellurium and antimony. In this process, the catalyst is subjected to heat treatment virtually in the absence of molecular oxygen, and then subjected to further heat treatment under a stream of air. However, in this prior art document, there is no description as to whether or not such a manner of heat treatment in that process is effective for the ammoxidation reaction of propane or isobutane.
Unexamined Japanese Patent Application Laid-Open Specification No. 8-225506 (corresponding to U.S. Pat. No. 5,534,650) discloses a method for performing an ammoxidation reaction of an alkane in which gaseous ammonia is fed into a reactor from a plurality of ammonia inlets provided therein. However, with respect to the manner of elevating the temperature of a catalyst before starting the ammoxidation reaction of an alkane, no description is found in this prior art document.
Japanese Patent Publication No. 2599677 (published in 1997)(corresponding to U.S. Pat. No. 5,332,855) discloses an ammoxidation method for a saturated hydrocarbon, using a catalyst which contains vanadium, antimony and at least one element selected from iron, gallium and indium; Examined Japanese Patent Application Publication No. 6-92355 (corresponding to U.S. Pat. No. 5,334,743) discloses an ammoxidation method for a saturated hydrocarbon, using a catalyst which contains molybdenum, vanadium and at least one element selected from manganese, zinc, cobalt, copper, lithium, sodium, potassium and silver; and Japanese Patent Publication No. 2506602 (published in 1996)(corresponding to U.S. Pat. No. 5,336,804) discloses an ammoxidation method for a saturated hydrocarbon, using a catalyst which contains vanadium, antimony and bismuth. In these prior art documents, there is a description about an evaluation method for the ammoxidation reaction, in which the temperature of a catalyst contained in a reactor is first elevated to 150.degree. C. while purging the air in the reactor with helium, and then feedstock gases and diluent gases, i.e., propane, ammonia, oxygen, steam and helium, are fed while further elevating the temperature of the catalyst to a predetermined temperature, for example, 300.degree. C., whereupon the catalyst temperature is maintained at the predetermined temperature for 30 minutes, followed by analysis of a gaseous mixture withdrawn from the outlet of the reactor. The present inventors conducted experiments in which the catalysts described in these prior art documents were produced and ammoxidation reactions were conducted using the produced catalysts individually to make various evaluations. As a result, it was found that the performance of the catalyst is almost not affected by the type of gas which is supplied into a reactor containing the catalyst during the elevation of the temperature of the catalyst before starting the ammoxidation reaction. More specifically, the catalyst exhibits the same performance irrespective of whether the gas used during the temperature elevation is air alone or air plus combustible gas selected from feedstock gases.
As a method for the ammoxidation of an olefin by using a catalyst which contains antimony and uranium, British Patent No. 1,304,665 discloses a method in which a catalyst bed comprising a regeneration zone and a reaction zone located adjacent to each other is provided, and molecular oxygen necessary for the ammoxidation is flowed through the regeneration zone of the catalyst bed, together with ammonia in an amount of 3% or more of the whole amount of ammonia to be fed. In this method, the feeding of ammonia to the regeneration zone is intended to suppress a loss of propylene in the regeneration zone. In this prior art document, there is no description as to the manner of elevating the temperature of the catalyst bed before the start of the ammoxidation reaction of propylene.
U.S. Pat. No. 4,814,478 discloses a method in which the ammoxidation reaction of a saturated hydrocarbon is performed using a mixed catalyst of a catalyst comprised mainly of vanadium and antimony and a catalyst comprised mainly of molybdenum, bismuth and iron. In this prior art document, as a specific example of the reaction method, a method using a fixed-bed reactor is described, wherein gaseous raw materials are preheated by means of a "preheat leg", and the resultant preheated gaseous raw materials are then introduced into a catalyst bed. However, this prior art document has no description as to the manner of elevating the temperature of the catalyst bed before starting the ammoxidation reaction.
U.S. Pat. No. 3,833,638 discloses a catalyst for use in the ammoxidation reaction of a saturated hydrocarbon. The catalyst contains molybdenum, cerium and at least one element selected from the group consisting of bismuth and tellurium. In this prior art document, it is described that gaseous raw materials can be fed to the reactor either before or after the internal temperature of the reactor reaches a desired reaction temperature. In this connection, it is noted that the catalyst of this prior art document is of a type such that the regeneration of the catalyst can be performed through contact with air at high temperatures. Therefore, with respect to the technique of this prior art document, it is preferred that the elevation of the internal temperature of the reactor toward a desired reaction temperature is performed while supplying air into the reactor, and the feeding of gaseous raw materials is started after the internal temperature of the reactor has reached the desired reaction temperature.
As described hereinabove, various proposals have been made to provide an improved process for producing an unsaturated nitrile by ammoxidation of an alkane (such as propane and isobutane) in the presence of a catalyst. However, such proposals have been disadvantageous in that the catalytic activity of the specific catalyst (comprising a carrier having supported thereon an oxide catalyst comprised of a compound oxide of molybdenum, vanadium, niobium and at least one element selected from the group consisting of tellurium and antimony) cannot be maintained at a high level when the ammoxidation reaction is performed. Therefore, it has been desired to develop an improved process for producing an unsaturated nitrile from an alkane by ammoxidation, which can maintain the catalytic activity of the catalyst at a high level even after the temperature of the catalyst is elevated to the ammoxidation reaction temperature.


A polymer, which contains a structural unit having a carboxyl group represented by the following formula (1) at a side chain of the structural unit, wherein no deposition is formed, when the polymer is dissolved in an alkali aqueous solution having a pH of 10 or more and kept at 25° C. for 60 days:

Heretofore, PS plates having an oleophilic photosensitive resin layer formed on a hydrophilic support have been widely used for lithographic printing plate precursors. For making printing plates from them, generally employed is a method of mask-exposing (surface-exposing) the precursor via a lith film followed by dissolving and removing the non-image area to obtain a desired printing plate. Recently, digital computing technologies have become much popularized for electronically processing image information, and accumulating and outputting the processed data by the use of computers. Various new-type image outputting systems that correspond to such digital technologies have now been put into practical use. As a result, a computer-to-plate (CTP) technique is desired that comprises scanning high-directivity light such as laser light in accordance with digitalized image information data for direct production of printing plates not via lith films, and it is now an important technical theme to obtain lithographic printing plate precursors suitable to it.
For such scanning-exposable lithographic printing plate precursors, a structure has been proposed, comprising an oleophilic photosensitive resin layer (hereinafter referred to as photosensitive layer or recording layer) that contains a photosensitive compound capable of generating an active species such as radical or Broensted acid through laser exposure, formed on a hydrophilic support, and its commercial products are now available on the market. The lithographic printing plate precursor of the type is laser-scanned on the basis of digital information to generate the active species, then the recording layer therein undergoes physical or chemical changes owing to the effect of the active species, thereby having an insoluble area, and then this is developed to give a negative lithographic printing plate. In particular, the lithographic printing plate precursor of a type having, formed on a hydrophilic support thereof, a photopolymerizable recording layer that contains a high-performance photopolymerization initiator, an addition-polymerizable ethylenic unsaturated compound and an alkali developer-soluble binder polymer, and optionally oxygen-blocking protective layer has various advantages in that its producibility is high, it may be developed in a simplified manner, its resolution is high and the ink acceptability of the printing plate from it is good, and therefore the precursor may give a printing plate having desired printing capabilities.
Heretofore, for the binder polymer to constitute the recording layer, used are organic polymers soluble in alkali developer, such as methacrylic acid copolymers, acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially-esterified maleic acid copolymers (for example, see JP-B 59-44615, JP-B 54-34327, JP-B 58-12577, JP-B 54-25957, JP-A 54-92723, JP-A 59-53836, JP-A 59-71048, and JP-A 2002-40652). In lithographic printing plate precursors having a recording layer that contains such an ordinary binder polymer, the solubility in alkali of the binder polymer in the non-image area tends to be insufficient. In particular, carboxyl group-having polymers of good alkali solubility are favorably used from the viewpoint of rapid developability. However, since the carboxyl group contains an ester bond in the linking group moiety to the terminal carboxyl group (—COOH) in the polymer, and since the ester bond moiety is hydrolyzed with time in developer, the polymer loses the terminal carboxyl group that is an alkali-soluble site. As a result, the binder polymer solubility in developer lowers, and the binder polymer once dissolved in developer during development therein may deposit to form development sediment, and it may impart a great deal of load to printing systems, or the deposited development sediment may adhere to printing plates to cause stains in prints. To that effect, the polymer binders have many problems.

Alkali-soluble polymer and polymerizable composition thereof

Abstract: wherein R1 represents a hydrogen atom or a methyl group; R2 represents an (n+1)-valent organic linking group containing an ester group represented by —O(C═O)—; A represents an oxygen atom or NR3—; R3 represents a hydrogen atom, or an monovalent hydrocarbon group having from 1 to 10 carbon atoms; and n indicates an integer of from 1 to 5.


A compound with a relative molecular mass of less than 15000 comprising the peptide Ile-Gly-Asp (IGD) or a peptide or non-peptide mimic thereof. The compounds may be used to modulate cell migration and are useful in angiogenesis.

1. Field of the Invention
The present invention relates to peptides and related compounds and in particular to peptides and related compounds which affect cell migration.
2. Description of the Related Art
Fibronectin is a widely distributed glycoprotein present at high concentrations in most extracellular matrices, in plasma (300 μg/ml), and in other body fluids. Fibronectin is a prominent adhesive protein and mediates various aspects of cellular interactions with extracellular matrices including migration. Its principal functions appear to be in cellular migration during development and wound healing, regulation of cell growth and differentiation, and haemostasis/thrombosis.
Fibronectin is a dimer of two non-identical subunits covalently linked near their COOH-termini by a pair of disulphide bonds. The difference between the subunits is determined by alternative splicing of the IIICS (or V) region. In the insoluble, matrix form of fibronectin, the dimer associates into disulphide-bonded oligomers and fibrils, while soluble, body fluid fibronectin is predominantly dimeric. Three regions of fibronectin are subject to alternative splicing and in general the matrix form of the molecule has a higher content of these segments than the soluble form. The human IIICS region has five potential variations, while the rat, bovine and chicken sequences have three, three and two, respectively. Each subunit is composed of a series of structurally independent domains linked by flexible polypeptide segments. At the primary sequence level, the origin of the majority of the fibronectin molecule can be accounted for by endoduplication of three types of polypeptide repeat. Different fibronectin domains are specialized for binding extracellular matrix macromolecules or bacterial or eukaryotic membrane receptors. The central cell-binding domain is recognised by most adherent cells via the integrin receptors α3β1, α5β1, αVβ1, αllbβ3, αVβ3, αVβ5 and αVβ6. The IIICS/Hepll cell-binding domain is recognised by lymphoid cells, neural crest derivatives and myoblasts via the integrins α4β1 and α4β7. Several peptide active sites have been identified in these domains.
Plasma fibronectin can be purified by a combination of gelatin and heparin affinity chromatography. Cell-associated fibronectin can be extracted from culture monolayers with 1 M urea. Further details on fibronectin are in The Extracellular Matrix Facts Book, Ayad et al (eds), Academic Press, Harcourt Brace & Company, London.
Limited proteolytic digestion of fibronectin results in the release of a number of its functional domains, which are characterised by their specific adhesion to other matrix macromolecules or integrin receptors on the cell surface (i.e. the cell-binding domain)1. The transmembrane assay has commonly been used to study the effects of fibronectin and its purified functional domains on cell migration in vitro. Essentially, this assay involves assessing cell movement through a polycarbonate membrane coated with an adhesive protein (usually gelatin) separating upper and lower medium compartments containing the putative effector molecule. Previous studies have revealed that nano- to micromolar concentrations of fibronectin and its purified cell-binding domain stimulate the migration of a wide range of cell types in the transmembrane assay2,3. Related studies implicated the RGD (SEQ ID NO 4) amino acid motif (located in the tenth type III repeat module) in mediating these effects of both native fibronectin and its cell-binding domain3. Significantly, small RGD-containing synthetic peptides did not stimulate cell migration; indeed, these peptides inhibited the adhesive and migration stimulating activity of larger protein domains containing the RGD (SEQ ID NO 4) motif by competition for receptor ligation4. In contrast to the activity of the cell-binding domain, the gelatin-binding domain of fibronectin has consistently been reported to be devoid of migration stimulating activity in the transmembrane assay2,5.
Schor et al (1994) Progress in Growth Factor Research 5, 223–248 is a review of cytokine control of cell motility and its modulation and mediation by the extracellular matrix. Schor et al (1993) In: Cell Behaviour: Adhesion and Motility (ed. G. Evans, C. Wigley and R. Warn) Society of Experimental Biology Symposium No. 47, pages 235–251 relates to migration stimulating factor (MSF).
Grey et al (1989) Proc. Natl. Acad. Sci. USA 86, 2438–2442 relates to the purification of the MSF produced by fetal and breast cancer patient fibroblasts.
U.S. Pat. No. 5,300,630 relates to oncodevelopmentally regulated antigens related to fibronectin.
U.S. Pat. No. 5,510,328 relates to methods of reducing or inhibiting wound contraction using certain peptides.
U.S. Pat. No. 5,354,736 relates to compounds that have enhanced cell binding with respect to collagen.
U.S. Pat. No. 4,976,734 relates to a method of stimulating chemotaxis towards a prosthetic device.
U.S. Pat. No. 4,980,279 relates to portions of fibronectin.
U.S. Pat. No. 5,049,658 relates to a polypeptide having the cell-spreading activity of human fibronectin.
U.S. Pat. No. 5,124,155 relates to wound healing dressings, which are prepared by flocculating fibronectin.
U.S. Pat. No. 5,453,489 relates to polypeptides, which encompass fibronectin—fibronectin binding sites and which are capable of inhibiting fibronectin matrix assembly.
U.S. Pat. No. 5,192,746 relates to compounds having the property of modulating cell adhesion.
U.S. Pat. No. 5,491,130 relates to peptides derived from human endothelial cell thrombosponding, which bind to the gelatin-binding domain of fibronectin.

Peptides containing the motif IGD and their use as cell migration modulators


A hair clip according to one embodiment of the present invention has a top surface and a bottom surface and at least one hook connected to the bottom surface. The hook is configured such that it has an open end. A hair band can slide under the open end of the hook and fit securely inside the hook.

1. Field of the Invention
The present invention relates generally to the field of hair accessories and more particularly to a hair clip having a replaceable hair band.
2. Description of the Related Art
Hair clips are commonly used for styling, accessorizing, and/or securing the hair. Conventional hair clips generally include a decorative part designed for aesthetic reasons and an elastic band permanently attached to the decorative part. Elastic bands have a lifetime that is generally shorter than the lifetime of the decorative part of a hair clip and the bands often break easily. Because elastic bands do not last very long, most hair clips become unusable after a short period of time. Thus, even though the decorative part of the hair clip may still be in good condition, the hair clip may no longer be used because of a broken elastic band.


A display input device includes a reception processing portion, a change processing portion, and a display processing portion. The reception processing portion, based on correspondence information indicating a correspondence between a plurality of characters and a plurality of operation keys used for inputting a password of a preset number of characters, receives an operation of any one of the operation keys as an input operation of a character corresponding to the operation key. The change processing portion changes the correspondence relationship when the operation of the operation key is performed a preset specific number of times that is less than the number of characters of the password, or at a preset specific interval. The display processing portion displays the correspondence information at a predetermined position, different from a position of the operation keys, on an input screen used for inputting the password.

The present disclosure relates to a display input device, an information processing apparatus including the display input device, and a display input method that is executed in the display input device.
In the information processing apparatus such as a personal computer, an authentication process for authenticating a user is executed. In this type of information processing apparatus, when the authentication process is executed, an input screen used for inputting a password is displayed on a display portion. Based on a password input on the input screen, it is determined whether or not authentication is successful.
Meanwhile, when a user inputs the password into the information processing apparatus, the password may become known to a third party from movement of the user's hand entering the password. On the other hand, there is a configuration known as a related technology in which correspondence relationship information indicating a correspondence relationship between a plurality of operation keys and a plurality of characters is displayed on the display portion, and based on the correspondence relationship information, the character that is input in response to an operation of any of the operation keys is identified.

Display input device for receiving password input, information processing apparatus, display input method


A method of carrying out mass spectrometry, comprising: using an electrostatic or electrodynamic ion trap to contain a plurality of ions, each ion having a mass to charge ratio, the ions having a first plurality of mass to charge ratios, each ion following a path within the electrostatic or electrodynamic ion trap having a radius; and for each of a second plurality of the mass to charge ratios: modulating the radii of the ions in a mass to charge ratio-dependent fashion dependent upon the mass to charge ratio; fragmenting the ions thus modulated in a radius-dependent fashion; and determining a mass spectrum of the ions.

Two-dimensional mass spectrometry (2D MS) is a technique that correlates precursor and fragment ions in a sample without requiring prior ion isolation. 2D MS was first proposed by Pfändler et al. in 1987 (P. Pfaendler, G. Bodenhausen, J. Rapin, R. Houriet, T. Gaumann. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry. Chem. Phys. Lett. 1987, 138, 195; P. Pfaendler, G. Bodenhausen, J. Rapin, M. E. Walser, T. Gaumann. Broadband two-dimensional Fourier transform ion cyclotron resonance. J. Am. Chem. Soc. 1988, 110, 5625; M. Bensimon, G. Zhao, T. Gaumann. A method to generate phase continuity in two-dimensional Fourier transform ion cyclotron resonance mass spectrometry. Chem. Phys. Lett. 1989, 157, 97) on a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) (M. B. Comisarow, A. G. Marshall. Fourier transform ion cyclotron resonance spectroscopy. Chem. Phys. Lett. 1974, 25, 282). The pulse sequence for 2D MS was inspired both by NOESY NMR spectroscopy (A. Kumar, R. R. Ernst, K. Wuethrich. A two-dimensional nuclear Overhauser enhancement (2D NOE) experiment for the elucidation of complete proton-proton cross-relaxation networks in biological macromolecules. Biochem. Biophys. Res. Commun. 1980, 95, 1) and by phase-reversion experiments performed Marshall et al. (A. G. Marshall, T. C. L. Wang, T. L. Ricca. Ion cyclotron resonance excitation/deexcitation: a basis for stochastic Fourier transform ion cyclotron mass spectrometry. Chem. Phys. Lett. 1984, 105, 233). Using two identical excitation pulses separated by a regularly incremented delay, ion cyclotron radii were modulated according to their cyclotron frequency (i.e. mass-to-charge ratio) before a fragmentation period with a radius-dependent fragmentation method (S. Guan, P. R. Jones. A theory for two-dimensional Fourier-transform ion cyclotron resonance mass spectrometry. J. Chem. Phys. 1989, 91, 5291). The resulting 2D mass spectrum shows the fragmentation patterns of all ions from the sample, which enables to easily extract fragment ion scans, precursor ion scans and neutral loss lines, as well as electron capture lines in some cases (M. A. van Agthoven, M.-A. Delsuc, G. Bodenhausen, C. Rolando. Towards analytically useful two-dimensional Fourier transform ion cyclotron resonance mass spectrometry. Anal. Bioanal. Chem. 2013, 405, 51). Since 2D mass spectra show the fragmentation patterns of all ions from a sample without requiring ion isolation, this technique can be said to be truly comprehensive and can be of great use for the analysis of complex samples.
Since 2010, thanks to improvements in computational capacities for data processing and storage, 2D MS on FT-ICR instruments has been developed into a fully-fledged analytical technique with infrared multiphoton dissociation (IRMPD) and electron capture dissociation (ECD) as fragmentation methods (M. A. van Agthoven, M.-A. Delsuc, C. Rolando. Two-dimensional FT-ICR/MS with IRMPD as fragmentation mode. Int. J. Mass Spectrom. 2011, 306, 196; M. A. van Agthoven, L. Chiron, M.-A. Coutouly, M.-A. Delsuc, C. Rolando. Two-Dimensional ECD FT-ICR Mass Spectrometry of Peptides and Glycopeptides. Anal. Chem. 2012, 84, 5589; M. A. van Agthoven, L. Chiron, M.-A. Coutouly, A. A. Sehgal, P. Pelupessy, M.-A. Delsuc, C. Rolando. Optimization of the discrete pulse sequence for two-dimensional FT-ICR mass spectrometry using infrared multiphoton dissociation. Int. J. of Mass Spectrom. 2014, 370, 114). De-noising algorithms have been developed in order to reduce the effects of noise in 2D mass spectra (M. A. van Agthoven, M.-A. Coutouly, C. Rolando, M.-A. Delsuc. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry: reduction of scintillation noise using Cadzow data processing. Rapid Commun. Mass Spectrom. 2011, 25, 1609; L. Chiron, M. A. van Agthoven, B. Kieffer, C. Rolando, M.-A. Delsuc. Efficient denoising algorithms for large experimental datasets and their applications in Fourier transform ion cyclotron resonance mass spectrometry. Proc. Natl. Acad. Sci. U.S.A 2014, 111, 1385.). 2D MS has been successfully applied to the analysis of small molecules (M. van Agthoven, M. Barrow, L. Chiron, M.-A. Coutouly, D. Kilgour, C. Wootton, J. Wei, A. Soulby, M.-A. Delsuc, C. Rolando, P. O'Connor. Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. J. Am. Soc. Mass Spectrom. 2015, 26, 2105) as well as in bottom-up (H. J. Simon, M. A. van Agthoven, P. Y. Lam, F. Floris, L. Chiron, M. A. Delsuc, C. Rolando, M. P. Barrow, P. B. O'Connor. Uncoiling collagen: a multidimensional mass spectrometry study. Analyst 2016, 141, 157; M. A. van Agthoven, C. A. Wootton, L. Chiron, M.-A. Coutouly, A. Soulby, J. Wei, M. P. Barrow, M.-A. Delsuc, C. Rolando, P. B. O'Connor. Two-Dimensional Mass Spectrometry for Proteomics, a Comparative Study with Cytochrome c. Anal. Chem. (Washington, D.C., U. S.) 2016, 88, 4409) and top-down (F. Floris, M. van Agthoven, L. Chiron, A. J. Soulby, C. A. Wootton, Y. P. Y. Lam, M. P. Barrow, M.-A. Delsuc, P. B. O'Connor. 2D FT-ICR MS of Calmodulin: A Top-Down and Bottom-Up Approach. Journal of The American Society for Mass Spectrometry 2016, 27, 1531) proteomics.
In 1993, Ross et al. proposed an alternative pulse sequence of 2D MS on an FT-ICR mass spectrometer (C. W. Ross, III, S. Guan, P. B. Grosshans, T. L. Ricca, A. G. Marshall. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry/mass spectrometry with stored-waveform ion radius modulation. J. Am. Chem. Soc. 1993, 115, 7854). Instead of using delays between pulses, this pulse sequence uses the fact that the cyclotron radius of an ion after excitation is proportional to the product of the excitation amplitude and the excitation length (M. V. Gorshkov, E. N. Nikolaev. Optimal cyclotron radius for high resolution FT-ICR spectrometry. Int. J. Mass Spectrom. Ion Processes 1993, 125, 1). Using stored waveform inverse Fourier transform techniques (SWIFT) (A. G. Marshall, T. C. L. Wang, L. Chen, T. L. Ricca. New excitation and detection techniques in Fourier transform ion cyclotron resonance mass spectrometry. ACS Symp. Ser. 1987, 359, 21), excitation pulses were generated with amplitudes that were modulated according to the excitation frequency. Applying these excitation pulses to precursor ions in the ICR cell modulated their cyclotron radii according to their cyclotron frequencies and therefore modulated the abundances of their fragments after radius-dependent fragmentation. This technique, called stored waveform ion radius modulation (SWIM), was applied to the analysis of amino acid dimers and trimers (G. van der Rest, A. G. Marshall. Noise analysis for 2D tandem Fourier transform ion cyclotron resonance mass spectrometry. Int. J. Mass Spectrom. 2001, 210/211, 101) and to the analysis of polymers and pharmaceutical products (C. W. Ross, W. J. Simonsick, Jr., D. J. Aaserud. Application of Stored Waveform Ion Modulation 2D-FTICR MS/MS to the Analysis of Complex Mixtures. Anal. Chem. 2002, 74, 4625). However, due to fact that SWIFT is not available on most commercial FT-ICR instruments, the original pulse sequence for 2D FT-ICR MS is easier to use than SWIM.
Although 2D MS shows good results on FT-ICR instruments, its development is hampered by the fact that FT-ICR instruments are expensive to purchase and maintain. Furthermore, due to the duty cycle of the FT-ICR mass spectrometer, each 2D MS experiment can take 30 minutes or more. Developing 2D mass spectrometry techniques that can be applied to other mass spectrometers is therefore important for the development of data-independent structural analysis of complex samples.
Linear ion traps (LIT) (J. C. Schwartz, M. W. Senko, J. E. P. Syka. A two-dimensional quadrupole ion trap mass spectrometer. J. Am. Soc. Mass Spectrom. 2002, 13, 659) are popular ion manipulation devices. Their dimensions allow for larger ion populations than quadrupolar ion traps (R. E. March. An introduction to quadrupole ion trap mass spectrometry. Journal of Mass Spectrometry 1997, 32, 351). Resonant mass-selective radial excitation is well-established with LITs (B. A. Collings, W. R. Stott, F. A. Londry. Resonant excitation in a low-pressure linear ion trap. Journal of the American Society for Mass Spectrometry 2003, 14, 622; D. J. Douglas, N. V. Konenkov. Mass selectivity of dipolar resonant excitation in a linear quadrupole ion trap. Rapid Communications in Mass Spectrometry 2014, 28, 430).


A handheld GPS jammer locator for locating a GPS jamming signal generated by a jammer. The handheld GPS jammer locator has two modes of operation, a amplitude mode and a difference finding mode. The amplitude measures the strength of an incoming GPS jamming signal and the difference finding mode determines the direction of the incoming jamming signal.

1. Field of the Invention
The present invention relates generally to electronic countermeasures. More specifically, the present invention relates to a handheld electronic device which is useful in locating a GPS jammer signal.
2. Description of the Prior Art
Emitting sources such as GPS jammers can be accurately located by highly classified airborne and space tracking devices. However these devices are few in number and may not be available in a timely manner. Also, visual confirmation of jammers at close range is not generally possible. The use of a handheld or mini remote piloted vehicles complement the capability of these devices to permit pinpoint destruction of the emitters, especially if the emitters are small and dispersed in large numbers.
Anti-jam capabilities incorporated in GPS receivers are limited in the number of simultaneously received jamming signals which can be suppressed. A large number of inexpensive jammers, as is expected to be deployed in a wartime scenario, will therefore render the GPS receivers useless. Such a situation also calls for a locating device capable of attacking the jammers without a large amount of collateral damage or excessive cost.
Vehicle mounted signal identification and location systems are large and expensive. The military's man portable LMRFDS system weighs 60 pounds, requires two soldiers to carry the system, and must be set up on the ground. The LMRFDS system is designed to be used against a wide variety of signals over a large frequency range, thus the system is complex and requires extensive training to operate. It and several other military used locating systems are to be replaced by the vehicle mounted Prophet Block system, leaving no man portable signal location systems in the military's inventory.
Technology is presently available for the production of small, inexpensive GPS jammers by potential adversaries, and these are beginning to appear, as has been noted in open literature. In a wartime environment, it is anticipated that these GPS jammers will be placed in or very near sensitive civilian facilities to prevent their destruction by large warhead precision guided munitions or anti-radiation missiles and without civilian casualties. In a peacetime environment, it is anticipated that these devices will be placed near airports or other facilities relying on GPS data. Even unintentional GPS jammers have been reported (i.e. active VHF/UHF antennas not working, interference due to civilian/military testing, etc.) to cause significant troubles in routine commercial operations. Accordingly there is a need to have a device which is hand held for use by ground personnel to locate and identify the jammers.

The United States of America as represented by the Secretary of the Navy


A lost foam pattern assembly comprising a crankcase section including first and second mounting surfaces, a right cylinder section which is fixed to the first mounting surface and which includes a primary locator, a left cylinder section which is fixed to the second mounting surface and which includes a primary locator, a transfer passage having an upper end located in the right cylinder section, and a transfer passage having an upper end located in the left cylinder section.

The invention relates to internal combustion engines, to lost foam casting processes and to methods for making internal combustion engines with lost foam casting processes. More particularly, the invention relates to foam pattern assemblies for making V-type engine blocks in lost foam casting processes, and to methods for machining engine blocks cast in lost foam casting processes.

Internal combustion engine and method for making same


A fiber optic sensing device uses a Fabry-Perot cavity to sense a physical parameter. The cavity modulates the incident polychromatic light. The modulated light is recorded by an optical spectrometer means. The spectrum is analyzed in a signal processing unit which normalizes the spectrum and determines the phase of the modulated signal. The phase, accumulated over whole range of wavelengths, has been used for identification of the physical parameter using a look-up-table. The cavity, the polychromatic light source and the spectroscope means are connected by fiber optic means.

The present invention relates to fiber optic sensing technology, and more specifically to a sensor and method using a Fabry-Perot optical interferometer and spectral signal demodulation for measurement of a physical parameter such as a pressure, a temperature, a strain, and a refractive index with a high accuracy and within a large range of physical parameters.
Fiber optic interferometric sensors offer a number of advantages over electrical sensors such as inherent immunity to electromagnetic interference, capability of operating in harsh environments and at longer distances, miniature sizes, etc. A fiber optic Fabry-Perot sensor typically consists of a measuring Fabry-Perot probe, a fiber optic extension cable and an opto-electronic module. The measuring Fabry-Perot probe represents a cavity with two partially reflective surfaces. The cavity modulates the spectrum of the incident light depending on cavity spacing and the refractive index of the media inside the cavity. Both, the cavity spacing and the refractive index define the optical path difference between the beams that are reflected from each reflective surface at certain wavelength. The optical path difference determines the conditions for maximums and minimums of the spectral modulation, which is changed with the physical parameter. The extension cable connects the probe to the opto-electronic module by means of transmitting the light from the light source to the probe and transmitting the modulated light back to the opto-electronic module for demodulation and further signal processing. The opto-electronic module includes a light source and a fiber optic coupling means for connecting the light source to the extension cable. The probe can be connected directly to the opto-electronic module if a long distance is not required.
Light sources which produce a broad spectrum light (polychromatic or white light sources) are cheap and less susceptible to thermal instability. They are preferred to be used in fiber optic sensors for wide industrial applications where the typical operating temperature is ranging from −40 C to +60 C. The returning light is demodulated in the opto-electronic module either by means of a second interferometer or by spectral means. Interferometric demodulation provides low signal-to-noise ratio unless mechanical scanning of the reference mirror is provided. Precise mechanical scanning may be done only in a stabilized environment which is costly to achieve and maintain. Spectral demodulation does not require mechanical scanning. It can be achieved by using conventional microspectrometers which have miniature size and robust design. Fiber optic spectroscopes are primarily based on diffractive gratings which provide linear spectra along the wavelengths. Modern diffractive gratings, in particular, holographic diffractive gratings have high efficiency and resolution along wide range of spectrum.
A number of techniques have been proposed for improving fiber optic interferometric sensors with spectral demodulation. U.S. Pat. No. 6,577,402, MILLER, Jun. 10, 2003 discloses a fiber optic interferometric sensor with spectral demodulation which is based on comparison of spectral light intensities taken at two wavelengths with the reference values recorded for the same wavelengths. The wavelengths are preferably selected at zero crossing locations where the spectral modulation has the highest contrast. Such a technique may be applied only for sensing the physical parameter within a narrow range. This range is limited by a half-period of the spectral modulation, and if the modulated optical spectrum shifts beyond its reference location, the two-point technique will indicate the value of the physical parameter which corresponds to the shift calculated from another fringe of the modulated spectrum.
A technique described in U.S. Pat. No. 6,141,098, SAWATARI et al., Oct. 31, 2000 is based on recording a calibration set of modulated spectra and comparing the measured spectrum with the calibration set. The modulated spectrum is normalized by subtracting the reference fringe pattern from the actual data fringe pattern, and then dividing by the average intensity of the reference pattern. However, such way of normalization requires both measuring and calibration conditions to be identical, which is difficult to achieve in practice. The measuring spectrum is changed with the fiber length, and also, from one opto-electronic module to another because of the spectral variability of the light sources. The deviation of the real measuring condition from the calibration condition, which is seen from the fluctuation of the average value in the referred document, leads to the higher inaccuracy because the measuring spectrum could not match with any stored calibrated data.
Another fiber optic interferometric sensor utilizing spectral decoding is described in U.S. Pat. No. 4,945,230, SAASKI et al., Jul. 31, 1990 and related documents. The sensor is based on a Fabry-Perot sensing interferometer with a very short optical path (two mirrors in a Fabry-Perot cavity are located closely). The interferometric pattern in such an arrangement has only one minimum which shifts with the physical parameter. The position of the interferometric minimum changes the proportion of light from each side of the minimum which can be registered by two photodetectors. Although simple, this method also has limited measuring range because the physical parameter can be measured within the fraction of a single fringe.
Also known in the art is the document TAPIA-MERCADO, et al., "Precision and sensitivity optimization for white-light interferometric fiber optic sensor", J. Lightwave Technol., v. 19, 2001, pp. 70–74 describing a zero-crossing technique in Sagnac fiber optic temperature sensors. The procedure of analyzing the shift in the interferometric pattern which includes determining the position of zero crossing points is based on normalization of the recorded spectra by calculating the two auxiliary spectra which are found by interpolating the maxima and minima of smoothed recorded spectrum. However, the interpolation error is increased with the smaller number of fringes in the spectrum and, consequently, the accuracy of the determination of the zero-crossing points is reduced.
Yet known in the art is the document EGOROV et al., "High reliable, self calibrated signal processing method for interferometric fiber-optic sensors", SPIE, v. 2594, 1996, pp. 193–197 describing a method for signal demodulation. The method is based on converting the optical spectrum into the optical frequency domain, calculating the Fourier transform of the converted signal, filtering the oscillating component, calculating the inverse Fourier transform and calculating a derivative of the final phase spectrum which gives the absolute value of the optical path difference. The conversion of the spectra from wavelength to optical frequency domain requires a long computation time because it must include a number of splining operations in order to achieve acceptable accuracy. This complexity increases the response time of the sensor making it too slow for sensing some physical parameters. The algorithm must include tracking of the oscillating frequency which is changed with the physical parameter. The value of the oscillating frequency is determined as a maximum in the amplitude part of the first Fourier transform which adds yet another complexity to the method and increases the response time of the sensor. No normalization has been proposed for this method based on assumption that spectral change of the light source will not affect the phase distribution.
Many applications require not only tracking the value of the sensing parameter, but measurement of the physical parameter in a large range. Such a requirement is typical of absolute temperature and pressure measurements for downhole applications in the oil and gas industry, or the measurement of strain in construction, etc.
Typically fiber optic sensors are installed in locations that are different from those where sensors were calibrated. The difference occurs due to the light attenuation in the extension cable, which can vary in length from one installation to another. Bending of the fiber affects the mode content which changes the intensity of the light coming to the opto-electronic module. Polychromatic light sources, such as LED's, in particular, usually have spectral power distributions that vary from unit to unit. Replacing the opto-electronic module requires recalibration of the probe. This is a complex task because it affects the sensing environment. For example, the recalibration of the pressure probe requires a depressurization of the pressurized vessel, which is associated with the interruption of the technological process. Recalibration is impossible in fiber optic strain sensors, which are used in construction because probes are permanently embedded into the concrete. Light sources are subjects to degradation with time and the aging reduces the total amount of light coming to the spectroscope, consequently causing the fluctuation of the average value. The latter introduces a systematic error in zero-crossing algorithms. Therefore, there is a need for a method and a sensor with a reliable normalization technique.
An object of the present invention is to provide a fiber optic sensing device based on white light interferometric method with spectral demodulation of the interferometric spectrum, for measuring a physical parameter within a range that is not limited by a single fringe of the modulated spectrum.
It is another object of the invention to provide such a fiber optic sensing device with a high accuracy and stability.
It is a further object of the invention to provide such a fiber optic sensing device with a possibility for in-field normalization of the signal and means for correcting the variation of spectral intensity of light caused by the bending of fibers and instability of the light source.

Fiber optic sensing device for measuring a physical parameter


A magnetic spacer system for a spinner of a rotorcraft includes a first ring of a plurality of magnets secured to the spinner and having an inner surface facing radially inward, and a second ring of a plurality of magnets secured to a nacelle of the rotorcraft and having an outer surface facing radially outward. The first and second rings of multiple magnets are arranged concentrically, and a portion of the inner surface of the first ring of a plurality of magnets and a portion of the outer surface of the second ring of a plurality of magnets have the same polarity to repel one another. In other aspects, the magnetic spacer system may be replaced by a low-friction system.

Spinner fairings, sometimes simply referred to as "spinners", are often employed to reduce the overall aerodynamic drag of an aircraft. Conventional spinners used with rotor systems (e.g., a tilt rotor system) may be in a fixed orientation with respect to a mast or nacelle. Spinners must be large enough to encapsulate various components of the rotor system (e.g., yoke, pitch links, etc.); however, in most cases, minimizing the size of the spinner is preferable to limit the amount of drag generated by the spinner. In addition to providing enough space for components of the rotor system itself, additional hardware to secure the spinner to the rotor system must be accounted for. Conventional spinners rely upon multiple spokes/supports to secure the spinner to the rotor system. It can be very difficult to route a spoke through the various rotor system components to both provide adequate support for the spinner while simultaneously allowing for proper range of motion of the rotor system components during operation (e.g., flapping, feathering, coning, etc.).


A new cultivar of Primula plant named ‘HAK-P-01’ that is characterized by a short overall height, a compact habit and flowers that have a red-purple upper side and a red-purple under side with a white base.

The present invention relates to a new and distinct cultivar of Primula plant botanically known as Primula filchnera×Primula sinensis and hereinafter referred to by the cultivar name 'HAK-P-01'.
'HAK-P-01' originated from the self-crossing of the female or seed parent Primula filchnera×Primula sinensis 'Thirtyone' (U.S. Plant Pat. No. 20,220) and the male or pollen parent Primula filchnera×Primula sinensis 'Thirtyone'. The crossing was conducted in February of 2007 in Aichi, Japan. The resulting seeds were subsequently planted and grown. The cultivar 'HAK-P-01' was selected by the inventor in February of 2008 in a controlled environment as a single plant within the progeny of the stated cross in a cultivated area of Aichi, Japan.
Asexual reproduction of the new cultivar 'HAK-P-01' first occurred by tissue culture in February of 2008 in Aichi, Japan. Since that time, under careful observation, the unique characteristics of the new cultivar have been uniform, stable and reproduced true to type in successive generations of asexual reproduction.


In an electroabsorption optical intensity modulator, a semiconductor buffer, a first semiconductor cladding layer, a semiconductor optical absorption layer, a second semiconductor cladding layer and a semiconductor cap layer are formed on a semiconductor substrate. Also, a first electrode is formed on the second semiconductor cap layer, and a second electrode is formed on a second surface of the semiconductor substrate. The semiconductor optical absorption layer includes a first semiconductor optical absorption layer element having a first absorption edge wavelength and a second semiconductor optical absorption layer element having a second absorption edge wavelength different from the first absorption edge wavelength.

1. Field of the Invention
The present invention relates to an electroabsorption optical intensity modulator.
2. Description of the Related Art
In a high speed optical communication system for long distance, semiconductor laser diodes have been broadly used to adopt a direct modulation method. In this system, however, a wavelength chirping phenomenon is generated during modulation, so that the waveform of a transmitted light signal on an optical fiber is deteriorated. This chirping phenomenon becomes critical as the transmission rate becomes larger and the transmission distance becomes longer. Particularly, in a communication system using 1.3 .mu.m zero dispersion fibers, even when a light source of a 1.55 .mu.m band having a low loss of fiber transmission is used to increase the transmission distance, this distance is limited by the dispersion limit due to the chirping phenomenon.
In order to reduce the chirping phenomenon, an external modulation system where an external optical modulator is used has been developed. As the external optical modulator, there are a dielectric modulator using LiNbO.sub.3 or the like and a semiconductor modulator using InP, GaAs or the like. The semiconductor modulator has an advantage in that the semiconductor modulator can be integrated with other optical elements such as a semiconductor laser diode and an optical amplifier and other electronic circuits such as a field effect transistor (FET) circuit, and also, the semiconductor modulator can be small in size and low in power supply voltage.
The semiconductor modulator is further divided into an electroabsorption optical intensity modulator and a Mach-Zendor type modulator. In the electroabsorption optical intensity modulator, the Franz-Keldysh effect for a bulk semiconductor or the quantum confined stark effect for multiple quantum wells (MQWs) is used. That is, the absorption edge is shifted toward the longer wavelength direction by applying an electric field to the modulator, so that the absorption coefficient is changed, thus modulating a light intensity. On the other hand, in the Mach-Zendor type modulator, the Pockets effect (electrooptic effect) for a bulk semiconductor or the quantum confined stark effect for MQWs is used. That is, the infractive index is changed by applying an electric field to the modulator.
The electroabsorption optical intensity modulator can remarkably reduce the waveform chirping phenomenon, as compared with the direct modulation system by the semiconductor laser diode; however, the waveform chirping amount cannot be zero. On the other hand, in the Mach-Zendor type modulator, the waveform chirping amount can be zero in principle; however, the Mach-Zendor type modulator is complex in structure and driving method due to the interference type structure where a non-linear waveguide structure is adopted.
A prior art electroabsorption optical intensity modulator includes a semiconductor buffer, a first semiconductor cladding layer, a semiconductor optical absorption layer, a second semiconductor cladding layer and a semiconductor cap layer are formed on a semiconductor substrate. Also, a first electrode is formed on the second semiconductor cap layer, and a second electrode is formed on a second surface of the semiconductor substrate. In the prior art electroabsorption optical intensity modulator, however, a positive chirping is usually generated. In addition, if the dewavelength between an incident light and the absorption edge wavelength of the semiconductor optical absorption layer is reduced, a negative chirping operation can be carried out. In this case, however, the absorption coefficient is increased, so that a sufficient output cannot be obtained at a signal ON state. This will be explained later in detail.
Recently, in the electroabsorption optical intensity modulator a prebias applying method is adopted to reduce the waveform chirping phenomenon, thus overcoming the limit of transmission distance caused by the dispersion. In a 10 Gb/s transmission, after a definite bias voltage is applied to the modulator, an electrical signal is superposed thereon, to enhance the duration of fiber dispersion, thus overcoming the limit of dispersion of transmission distance (see: K. Yamada et al., "Low-chirp, Low-polarization Dependent Characteristics of Electroabsorption Optical Intensity Modulator with an InGaAsP Bulk" IEICE, Technical Vol. 1, p. 349, C-349, 1995). Also, in a 10 Gb/s transmission, a definite bias voltage of 1.1V is applied to the modulator integrated with a distributed feedback (DFB) laser diode, to enhance the duration of fiber dispersion, thus obtaining a transmission distance of 100 km (see: K. Morita et al., "10 Gb/s Transmission over 100 km of Standard Fiber with a Blue Chirp Modulator Integrated DFB laser", IEILE, Technical Vol. 1, p. 301, C-301, 1995). However, when a bias voltage is applied to the modulator, an outgoing light power at a signal ON state is reduced, and thus, the signal ON/OFF ratio is deteriorated. In addition, a circuit for generating such a bias voltage is required, thus making the optical system complex.

Electroabsorption optical intesity modulator having a plurality of absorption edge wavelengths


An optical scanning device for scanning a dual-layer optical record carrier. The device includes a spherical aberration compensation optical subsystem having a switchable liquid crystal cell (10) for altering a wavefront deviation generated in a folding mirror (32) including a non-periodic phase structure (NPS) located behind a polarization-selective reflective layer.

1. Field of the Invention
This invention relates to an optical scanning device, and an optical element for use therein, for scanning an optical record carrier, such as an optical disk, comprising an information layer, the device comprising a radiation source for generating a radiation beam and an objective lens, located in an optical path between the radiation source and the information layer, for converging the radiation beam to a spot on the information layer. In particular, but not exclusively, the invention relates to an optical scanning device including an optical element to compensate for spherical aberrations generated by different optical path lengths (referred to herein as information layer depths) through which the beam travels in an optical disk to reach an information layer in the disk.
2. Description of the Related Art
There is a need for the production of optical record carriers of high capacity. Therefore, optical scanning devices using a relatively short wavelength radiation beam, for example, a radiation beam of 400 nm, and a high numerical aperture (NA) objective lens system, at least 0.7 and, for example, NA=0.85, are desirable. Furthermore, the capacity can be increased by providing a dual layer disk. At the wavelength and NA mentioned, a layer separation of at least 20–30 μm is desirable in order to reduce the coherent cross talk to an acceptable level. Without compensating measures, refocusing from one layer to the other results in spherical aberration, generating a wavefront error of 200–300 mλ root mean square optical path difference (OPD (rms)), which deteriorates the resolution of the optical spot formed.
It is known to mechanically adjust the spacing of the two, or more, lens elements of a compound objective lens, in order to provide spherical aberration compensation. Another method of compensation is by mechanically adjusting the position of a collimator lens with respect to the radiation source, so that the radiation beam impinges on the objective lens as a convergent, or divergent, instead of collimated, beam. Each of these methods compensates spherical aberration generated in the optical system of the scanning device, to at least approximately cancel out that generated in the optical disk being scanned.
However, using mechanical actuators to provide spherical aberration compensation, particularly when a separate mechanical actuator is used to provide focus control, is relatively complex and, therefore, increases the cost of manufacture of the scanning device.
A further known optical scanning device is described in International Patent Application No. WO-A-01/24174, corresponding to U.S. Pat. No. 6,567,365, in which a radiation beam is passed through a twisted nematic (TN) liquid crystal cell which selectively rotates the polarization of incident light by 90°. The beam is then passed, when in a convergent state, through a birefringent plate to produce spherical aberration therein. The birefringent plate produces different amounts of spherical aberration depending on the state of the TN cell, to compensate for the different information layer thicknesses.
European Patent Application No. EP-A-0865037 A1, corresponding to U.S. Pat. No. 6,215,756, and an article in Applied Optics, volume 38 (1999) pp 3778–3786 by R. Katayama, describe a phase structure which is used to make an objective lens designed for scanning DVD record carriers also suitable for scanning CD record carriers. In general, DVD record carriers are designed for being scanned with a radiation beam of a wavelength and numerical aperture different from that used for scanning a previous generation of record carriers, such as CD. The phase structure consists of stepped non-periodic annular zones, such that each zone gives rise to a phase step which is equal to a multiple of 2π for the DVD wavelength (660 nm), so that the phase structure has no effect at this wavelength. For CD read out, however, a different wavelength is used (785 nm). Consequently, the stepped phase profile results now in phase steps which no longer are equal to a multiple of 2π. With a proper design of the steps heights and zone width, the phase introduced by the phase structure in the CD case reduces the wavefront aberration caused by the information layer depth difference to below the diffraction limit. The structure is capable of reducing the wavefront aberration for two discrete wavelengths.
Japanese Patent Publication No. JP-A-2000-163791 describes a diffraction grating for an optical head for an optical scanning device capable of operating at two different wavelengths. Two different radiation sources are used and a grating is located behind a dichroic reflector forming a folding mirror for directing the radiation towards an objective system. The diffraction grating is a periodic structure, i.e., one which regularly repeats across the element. For one wavelength, the dichroic reflector reflects the radiation beam without diffraction, while for the other wavelength, the dichroic reflector transmits the radiation beam and the grating diffracts the radiation. In this way, while the optical axes of the beams emanating from the two radiation sources do not initially coincide, the beams pass coaxially through the objective system. Due to the diffraction, a certain amount of the input light is wasted, which is undesirable.