Acoustic emissions are detected by reflecting microwave radar signals off of an object, receiving reflected radar signals, generating an intermediate frequency, and filtering the intermediate frequency to remove low frequency signals associated with object movement and not acoustic emissions. A microwave Doppler radar detector provides the signals, a band-pass filter filters the intermediate frequency signal, and resulting signal is collected and analyzed to establish a relationship between the acoustic emission and the filtered signal. One application described is detecting tool wear using a microwave Doppler-based acoustic emission sensor and predicting tool wear based on the detected acoustic emission.

The present invention relates to acoustic emission. More particularly, the present invention relates to detecting acoustic emissions using a microwave Doppler radar detector.
1. Acoustic Emission
ASTM E 610-89a (1990) defines acoustic emission (AE) as "the class of phenomena whereby transient elastic waves are generated by the rapid release of energy from a localized source or sources within a material, or the transient elastic waves so generated" (p. 269). Li (2002) states that, "Clearly, an AE is a sound wave or, more properly, a stress wave that travels through a material as the result of some sudden release of strain energy" (p. 157).
Investigators have developed many acoustic emission (AE) instruments and systems for both monitoring and nondestructively testing structures, materials, manufacturing processes, and devices. AE has been used for nondestructively testing refineries, pipe-lines, power generators (nuclear or other), aircraft, offshore oil platforms, paper mills, and structures (bridges, cranes, etc.). AE sensors have also been used for quality control in manufacturing operations and in research applications, involving composite structures such as fiberglass, reinforced plastics, and advanced aerospace materials (Li, 2002).
AE is also generally rated one of the most effective indirect methods for monitoring tool condition in machining operations. The major advantages of using AE to monitor tool condition are that (1) the frequency range of the AE signal is much higher than that of the machine vibrations and environmental noises, and (2) AE measurements do not interrupt cutting operations (Li, 2002).
As shown in FIG. 1, possible sources of AE during metal-cutting processes include:                1. Plastic deformation in the workpiece during the cutting process;        2. Plastic deformation in the chip;        3. Frictional contact between the tool flank face and the workpiece, resulting in flank wear;        4. Frictional contact between the tool rake face and the chip, resulting in crater wear;        5. Collisions between chip and tool;        6. Chip breakage;        7. Tool fracture.
Based upon analysis of AE signal sources during machining, AE consists of both continuous and transient signals, which have distinctly different characteristics. Continuous signals are associated with shearing in the primary zone and wear on the tool rake and flank faces. Burst or transient signals result from either tool fracture or chip breakage. Friction between workpiece and tool and tool fracture are regarded as the most important sources of continuous and transient AE signals in turning operations (Li, 2002).
2. Early AE Sensors
In 1996, Drouillard provided a comprehensive history of early acoustic emission research. Relevant highlights from his article follow.
In the early 1900s, metalworkers often reported audible sounds (clicking, chatter; squeaks, grinding, hissing, and snapping) emitted by metals, particularly tin and zinc, during twinning and martensitic transformation. Soon thereafter, several investigators conducted instrumented experiments to study the phenomenon (Drouillard, 1996).
From 1925-1929, Klassen-Neklyudova (National Physical-Technical Rontgen Institute in Leningrad, Russia) began a systematic investigation into the very regular cracking noises emitted during plastic deformation of metals. She used an optical method to measure stepwise, jerky movements of a metal specimen during plastic deformation and then correlated the measurements with the cracking noises (Drouillard, 1996).
On Nov. 21, 1933, at a meeting of the Earthquake Research Institute in Tokyo, Professor Fuyuhiko Kishinouye presented the first report on a scientifically planned acoustic emission experiment. Kishinouye studied AE characteristics in wood to understand and develop methods for studying fracture of the earth's crust, which leads to earthquakes. He used a phonograph pick-up with a steel needle to measure stress waves in a wooden board which he bent to fracture. He reported that when the board cracked, an electric current was generated in the coil of the pick-up, which he then amplified and used to drive a seismograph. Kishinouye reported that the instrument recorded both audible and inaudible vibrations during both the bending process and final fracture (Drouillard, 1996).
From 1936-1940, Forster and Scheil (Kaiser-Wilhelm-Institut fur Metallforschung, Stuttgart, Germany) conducted several AE experiments. They developed an electrodynamic transmitter/receiver system to transform mechanical vibrations and acoustic emissions into electrical voltages which could be amplified and recorded. They used the device to measure extremely small voltage changes due to resistance variations produced by sudden, jerky strain movements caused by martensitic transformations in wire-shaped nickel-steel test specimens (Drouillard, 1996).
In 1948, Mason, McSkimin, and Schockley (Bell Telephone Laboratories, Murray Hill, N.J.) reported using a quartz crystal transducer, pressed directly against a tin specimen, to measure acoustic emission. They applied enough stress to deform the specimen and cause twinning dislocations, which, in turn, produced acoustic emission. The quartz crystal they used had a uniform sensitivity from a few kilohertz to 5 MHz (Drouillard, 1996).
In the early 1960s, a special projects team of structural test engineers, led by Allen T. Green (Aerojet-General Corporation, Sacramento, Calif.), used AE measurements to verify the structural integrity of glass-filament-wound Polaris solid rocket motor cases fabricated for the U.S. Navy. They noticed that hydrostatic proof-pressure tests caused audible sounds in the test specimen. The team used microphones, a magnetic tape recorder, and sound-level analysis equipment to detect, record, and then post-test analyze the acoustic signals. Later, they used accelerometers and charge amplifiers to improve their detection capability. In 1965, the team used the method to locate crack initiation and propagation prior to catastrophic failure, at about 56 percent proof pressure, in a steel solid rocket motor case. Their multi-channel analog computer-based system was used to build the first commercial, real-time structural testing system (Drouillard, 1996).
In 1963, Harold Dunegan (Lawrence Livermore National Laboratory, Livermore, Calif.) began a lifelong career in AE, after hearing a paper presentation at the Third Symposium on Physics and Non-Destructive Testing. With co-workers, Dunegan developed practical AE procedures to predict failure in pressure vessels during proof testing, without taking the vessels to failure. He also developed the S140 transducer, which became the workhorse of the AE industry for over 25 years. Dunegan contributed significantly to AE study by developing more effective instrumentation, which eliminated noise due to mechanical vibration of the test specimen. In particular, he developed narrow-banded piezoceramic sensors which operated in frequency ranges well above the audio range (30-150 kHz). (Drouillard, 1996; Dunegan & Harris, 1969).
In the late 1960s, the U.S. Atomic Energy Commission began using AE techniques for nondestructive nuclear reactor testing. They used existing AE sensors, including accelerometers with charge amplifiers and tape recorders, and developed a new high-temperature submersible microphone for use in the liquid sodium environment of a reactor (Drouillard, 1996).
During the late 1960s and early 1970s the Boeing Company (Seattle, Wash.) initiated research on incipient failure detection in bearings, signature analysis from rotating machinery, leak detection in hydraulic systems, and cavitation and erosion detection in fluid flow valves. They also studied crack growth in titanium (Drouillard, 1996).
From 1967-1980, strong AE research helped determine the source of AE and improved methods for detecting crack growth in nuclear reactor pressure vessels and other thick-walled vessels. AE research efforts during the period led to development and commercialization of AE source location instrumentation and software. In 1968, Nortec Corporation (Richland, Wash.) manufactured a plug-in module for the Tektronix oscilloscope. Later that year, Dunegan founded Dunegan Research Corporation (Livermore, Calif.) to supply the first full line of AE sensors and modular instruments. Other U.S. companies also entered the market: Trodyne (Teterboro, N.J., 1970), Acoustic Emission Technology (Sacramento, Calif., 1972), and Physical Acoustics (Princeton, N.J., 1978) (Drouillard, 1996).
From 1980-1996, decline in heavy industry, decline in the use of nuclear reactors for power generation, and the end of the Cold War and break-up of the Soviet Union (and, thus, less defense spending) slowed AE research and instrumentation development, in some areas. In other areas, however, AE activity grew. Fowler (Monsanto Company, St. Louis, Mo., 1984) developed an AE inspection program that virtually eliminated catastrophic failures in fiber reinforced plastic vessels and piping. A number of AE studies related to tool wear and cutting processes, machine monitoring, bearing friction, and friction in rotating members were reported. Deterioration of many concrete bridges around the world led to increased AE research related to monitoring concrete and civil structures. According to Drouillard, in 1996, the U.S. Department of Transportation rated one in three U.S. bridges either structurally deficient (unable to support standard loads) or functionally obsolete. Seismology studies, for earthquake detection and mine failure prediction, mirrored studies of AE in metals and other materials, since rocks and metals under stress produce similar acoustic emission events. During the period, research related to AE in wood and AE methods for inspecting wood and wood products for defects, cracks, or pests also increased (Drouillard, 1996).
From 1980-1996, several new AE sensor or signal processing techniques were developed. Rockwell International and the National Bureau of Standards developed capacitive transducers to detect burst-type AE. (Drouillard, 1996). At the Virginia Polytechnic Institute, Stiffler and Henneke (1983) designed and tested AE sensors made from polyvinylidene fluoride (PVDF), a piezoelectric polymer which was originally discovered by Kawai (1969). Other investigators introduced digitizers and computers to capture, process, and analyze AE signals (Drouillard, 1996).
3. Recent AE Sensors
During the time period since Drouillard's review (1996-2002), studies related to developing new AE sensor technologies have focused primarily on new piezoelectric sensor materials or new sensor geometries.
Spedding (1996) explored the effects of geometry on thin-film polyvinylidene fluoride (PVDF) AE sensors. He showed that sensor geometry significantly affects sensor frequency response. His results show that thin-film PVDF could be used for developing frequency-selective, directionally sensitive, or programmable sensors.
Imai et al. (1997) developed a compact thin-film AE sensor for detecting head-disk interaction in magnetic disk devices. They used micromachining techniques to embed the sensor inside the slider, by sputtering a zinc oxide (ZnO) piezoelectric layer between two electrodes formed by electron beam deposition. Using both simulations and experiments, they showed that an embedded thin-film sensor is a viable alternative to conventional lead zirconate titanate (PZT) piezoceramic AE sensors for detecting head-disk interaction.
Brown et al. (1999) developed a piezoelectric sensor using a copolymer composed of polyvinylidene fluoride and triflouroethylene (PVDF/PTrFE). They experimentally compared their sensor to a commercial PZT piezoceramic sensor and a laser interferometer using pencil lead fracture and helium jet AE tests. They also evaluated their sensor, in field tests, for detecting fluid and mechanically generated acoustic emission in a centrifugal pump and a turbocharged diesel engine. Brown et al. concluded that a copolymer piezoelectric AE sensor can be used as a viable alternative to piezoceramic sensors or laser interferometers, while providing a more broad-band and detailed response than resonant piezoceramic sensors.
Sundaresan et al. (2002) developed a continuous or distributed AE sensor composed of PZT piezoceramic fibers suspended in a flexible epoxy matrix. They showed that using a continuous sensor could be more efficient for monitoring large areas on complex structures (e.g., for in-flight aircraft structural health monitoring) than using several conventional AE sensors; a continuous sensor is easier to mount and only requires a single data collection channel for a single sensor strip.
Schoess and Zook (1998) introduced a fundamentally new contact AE sensing technique. They used Honeywell's resonant microbeam MEMS sensor to experimentally show that the frequency of a resonating microbeam mounted in a silicon substrate varies in response to simulated AE events (ultrasonic pulsers and pencil lead fracture tests) applied to the silicon substrate. They believe the sensor shows promise for structural and machinery diagnostic applications.
4. AE Sensors for Tool Condition Monitoring
Most early research studies related to tool condition monitoring during machining operations used piezoceramic or piezoelectric sensors for acoustic emission detection (McBride et al., 1993). Piezoceramic sensors produce a dynamic voltage in response to stress waves, when a static electric field is applied to the sensor material. Piezoelectric sensors use materials which are naturally polarized (or which are polarized during manufacturing processes) to reduce the magnitude of the static electric field needed to bias the sensor (Swanson, 2000).
For tool-wear monitoring, placing a piezoceramic or piezoelectric sensor in contact with the workpiece or cutting tool causes stress (sound) waves traveling through the workpiece or tool to also travel through the sensor. As a result, the sensor generates electrical voltages proportional to the stress waves.
The piezoceramic or piezoelectric transducer must have good acoustic coupling to the source of AE. Often, however, mounting a piezoceramic or piezoelectric sensor in contact with the workpiece interferes with machining operations. As a result, the sensor often needs to be placed in contact with parts of the machining bed or tool holder, which attenuates the AE signals, modifies their spectral and temporal properties, and introduces noise from other sources in the machine (e.g., spindle bearing noise and slideway movement) (McBride et al., 1993).
Piezoceramic materials also give rise to strong mechanical resonances, which results in high sensitivity in only a few narrow frequency bands within the spectrum of interest. Although sensors with narrow sensitivity bands effectively eliminate low-frequency machine noise, they also may miss significant AE events outside their limited sensitivity ranges. The precise electromechanical properties of piezoceramic and piezoelectric transducers also vary from unit to unit. As a result, users must individually calibrate devices. Even with calibration, results strongly depend on the quality of the mechanical coupling between sensor and sensed surface, which, in practice, varies greatly (McBride et al., 1993).
Due to the limitations of piezoceramic and piezoelectric AE sensors, McBride, et al., (1993) developed a technique for detecting tool wear based on laser interferometry. They used a laser light source and fiber optics to produce a miniature and robust probe for detecting acoustic emission by measuring the small amplitude (˜0.1 nm), high frequency (0.1-1 MHz) surface vibrations produced during machining operations. They also demonstrated the technique for probing both the workpiece and the rotating tool holder during face milling of mild steel.
Barton and Reuben (1996) also used laser interferometry to measure both acoustic emission (AE) and surface finish (SF) for monitoring tool insert condition. Their AE and SF sensors used an optical fiber to connect a probe head near the workpiece to optical and detection systems remote from the machining center.
AE sensors for tool condition monitoring, based upon laser interferometry, place a small fiber optic probe approximately 20 mm from a plane end face of the workpiece. Laser light sent through the fiber optic cable reflects off of the face of the workpiece. Reflected light interferes with incoming light, based upon distance from the probe to the workpiece face. Signal processing techniques can be used to determine the instantaneous distance from the probe to the workpiece, based upon measured interference patterns, and, thus, determine characteristics of the stress (sound) waves traveling through the workpiece. Laser interferometer measurements can detect target displacements of less than 1 nm (Barton & Reuben, 1996).
Interferometry offers a highly sensitive method for measuring displacement or vibration that can achieve more accurate acoustic emission measurements than contacting piezoelectric transducers located on the machine bed. Interferometry can also be used for accurate non-contact surface finish (SF) measurement in machining operations (Barton & Reuben, 1996).
According to Barton and Reuben (1996), the greatest advantage of optical AE and SF measurement techniques are that they are non-contacting, with no mechanical loading of the test surface. As a result, optical AE measurement techniques guarantee reproducibility of coupling between the transducer and the measured surface. Optical SF measurement techniques also eliminate the possibility of damaging soft surfaces during measurement. In addition, output signals from interferometry are directly traceable to the light wavelength used and are, therefore, absolutely calibrated.
Limitations of AE sensors using laser interferometry include: high cost, small distance required between probe and workpiece, limitations of workpiece geometry (for proper laser light reflection), appearance and routing of the fiber-optic cable, interference with tool movement, and signal contamination due to coolant fluids and other contaminants
In more recent tool condition monitoring research, investigators have pursued a multi-sensor approach, combining piezoceramic, piezoelectric, or optical AE sensors with other types of sensors, to improve tool condition monitoring accuracy over single-sensor methods.
Chi and Dornfield (1998) combined both piezoceramic acoustic emission and cutting force sensors, with an expert system using decision trees and group method data handling, to improve tool wear estimation and prediction accuracy (to within 5% of measured values) over a model created using stepwise regression analysis.
Quan, et al. (1998) also used a multi-sensor approach, by combining an acoustic emission sensor and a Hall-effect power sensor, to detect tool wear with 96% accuracy and calculate actual tool wear with 90% accuracy. They concluded that using a multi-sensor approach, with a neural network to evaluate the multi-sensor data, improves tool wear detection accuracy over a single-sensor method under complex and changing machining conditions.
In 2002, Sick reviewed 138 prior publications related to tool wear monitoring in turning operations. At that time, Sick still rated even the most promising tool wear monitoring methods not marketable due to lack of precision and insufficient generalization capability (operation restricted to a single machine tool, to a specific combination of work material and tool coating, or a small range of cutting conditions).
From Sick's (2002) review, tool wear monitoring remains a difficult problem yet to be solved. From the research to date, machining processes have been classified as non-linear time-variant systems, which are difficult to model. In addition, sensor limitations have made machining processes difficult to measure.
Prior AE studies, particularly studies related to tool condition monitoring in machining operations, have led to two primary types of AE sensors: piezoceramic or piezoelectric crystals and laser interferometry systems.
For tool condition monitoring, piezoceramic and piezoelectric sensors exhibit severe limitations. To operate properly, they must be in contact with an object through which the acoustic waves are traveling. Investigators cannot practically install sensors on the tool or workpiece. Thus, they usually place sensors on the machining bed or tool holder. Sensor placement away from the workpiece leads to signal attenuation, modified spectral and temporal properties, and added noise from other sources in the machine (e.g., spindle bearing noise and slideway movement).
Piezoceramic materials also give rise to strong mechanical resonances, which can result in adequate sensor sensitivity in only a few narrow frequency bands within the spectrum of interest. The precise electromechanical properties of such transducers also vary from unit to unit, so that users must individually calibrate sensors. Even with calibration, results depend strongly on the quality of the mechanical coupling between transducer and surface, which, in practice, varies greatly.
AE sensors based upon laser interferometry also suffer from severe limitations. They require a small distance between sensor probe and workpiece. As a result, users may find it difficult to precisely mount the sensor probe and route the sensor's fiber-optic cable. In addition, the sensor and cable may interfere with tool movement during machining operations and detract from machine appearance. Laser interferometry-based sensors also suffer from signal contamination due to coolant fluids and other optical contaminants. In addition, laser systems are typically expensive.
Therefore, it should be appreciated that the prior art discloses numerous examples of AE sensors which have problems or disadvantages in particular applications.
Although seemingly unrelated without having the benefit of the present disclosure, the use of microwave Doppler radar detectors are now discussed. A microwave Doppler radar detector is designed to "sense" object motion using the Doppler shift phenomenon. The detector emits a high-frequency electromagnetic signal. If the signal reflects off of an object moving toward or away from the sensor, the transmitted signal increases or decreases in frequency, with respect to the original transmitted signal frequency. A receiver in the Doppler radar detector captures the reflected signal, compares the transmitted and received frequencies, and produces an IF (intermediate frequency) output signal with frequency proportional to the velocity of the moving object. IF output signal amplitude varies as a complex function of the size and reflectivity of the sensed object and the object's distance from the sensor (Microwave Solutions, 2002).
Microwave Doppler radar has been used in many practical applications, such as law enforcement systems for detecting automobile speed and commercial systems for opening doors as customers approach department stores. However, to the inventor's knowledge, microwave Doppler radar has never been used to directly detect acoustic emission.
Surface acoustic wave (SAW) devices, based upon microwave radar technology, have been used, for many years, to create many different non-contact wireless sensors (Bulst et al., 2001):                1. Temperature sensors (radio-requestable clinical thermometers; temperature sensors on rotating turbine blades, train brakes, centrifuges, and tires; temperature sensors in hot, dangerous, or inaccessible process chambers)        2. Pressure sensors        3. Torque sensors (tap drill torque alarm)        4. Current sensors        5. Chemical sensors        6. Humidity sensors        7. Mechatronic applications
The SAW approach uses a microwave radar signal to interrogate a sensor composed of a microwave antenna etched on a material substrate which responds to a given physical condition in a known manner (Steindel, et al., 1999). The antenna converts the interrogating radar signal into a surface acoustic wave which propagates along the substrate and reflects off of metal strips etched on the surface of the substrate at known distances from the antenna. The acoustic wave reflections return to the antenna and transform back into microwave signals which then transmit substrate condition information to a remote receiver.
As the SAW sensor substrate contracts, elongates, or bends in response to surrounding physical conditions, returned signal characteristics change. Users can then determine physical conditions affecting the substrate by processing and analyzing returned signal characteristics. Using different substrate materials creates sensors which can be used to measure different physical environmental properties.
Tyren (2001), in an international patent application (WO 01/73389 A1), describes a non-contact method for measuring mechanical properties such as torque, force, or pressure. The described method uses a vibrating string element to sense changes in the measured quantity and a microwave interrogating signal. Variations in the measured quantity change the tension in the vibrating string, and thus change the vibration frequency of the string element. Changes in vibration frequency of the string element change the amplitude of the microwave interrogating signal.
According to the patent application, "a microwave signal can be amplitude modulated by a mechanically oscillating object in the signal path between a transmitter and receiver" (Tyren, 2001, p. 1). The patent application also describes experiments conducted to verify the phenomenon, using an approximately 10 cm long guitar string segment, in oscillation at 150 Hz, to amplitude modulate a 1.3 GHz microwave signal.
By changing the oscillation frequency of the guitar string to 230 Hz, the inventor measured a change in microwave signal amplitude modulation that followed the change in frequency.
The patent application further describes several possible applications for the phenomenon, including a method for measuring the torque in a rotating axle. The method uses a string element placed along a main tension line of the axle. A mounting mechanism holds the string away from the surface of the axle, so that the string can oscillate freely. Natural system vibrations, or a clapper, induce string vibration. As torque in the axle changes, the oscillation frequency of the string also changes. Again, a high-frequency electromagnetic signal source radiates the vibrating string. Variations in the amplitude of the reflected high-frequency signal indicate variations in torque within the rotating axle. Tyren reportedly used a microwave Doppler radar detector and a band-pass filter tuned to the vibration frequency of a metal guitar string to detect changes in torque due to cutting operations on a manual lathe.
In an earlier study, the inventor worked with Tyren to evaluate his sensor design for detecting changes in torque due to cutting operations on a CNC lathe. Tyren supplied a hand-made microwave radar detector and a band-pass filter needed to detect a vibrating guitar string. The hand-made microwave radar system did not work. As a result, Tyren recommended using an MDU 1620 Motion Detector Unit from Microwave Solutions (http://www.microwave-solutions.com) as a microwave radar source and described the characteristics of a band-pass filter needed to detect a vibrating guitar string. The inventor designed a circuit composed of the Microwave Solutions Motion Detector Unit and a band-pass filter to meet Tyren's specifications for detecting a vibrating guitar string. In testing, the circuit did not appear to work well for detecting torque changes due to cutting operations on a CNC lathe, because workpiece and lathe spindle motion created radar detector signals that were much greater in magnitude than the signals created by a vibrating guitar string attached to the rotating workpiece.
Therefore, it is a primary object, feature, or advantage of the present invention to improve upon the state of the art.
It is a further object, feature, or advantage of the present invention to overcome the limitations of current piezoceramic, piezoelectric and laser-interferometry AE sensors.
Another object, feature, or advantage of the present invention is to provide a method and apparatus for an AE sensor which is economical, yet accurate.
Yet another object, feature, or advantage of the present invention is to provide an AE sensor appropriate for tool condition monitoring in machining operations as well as other applications.
These and/or other objects, features, or advantages of the present invention will become apparent from the specification and claims that follow.

Method for detecting acoustic emission using a microwave Doppler radar detector


A signal reproduction circuit includes: an oscillator generating first clock and second clock having a same frequency but different phases; and a feedback circuit to control the oscillator in accordance with a phase relation and a frequency relation between input data and the first clock, wherein the feedback circuit includes: a frequency-phase detection circuit to compare a clock phase control signal and a clock phase detection signal and generate a frequency phase signal indicating the frequency relation between the input data and the first clock, a state detection circuit to detect a lock state in which falling edges or rising edges of the input data and the first clock synchronize and a frequency difference state in which frequencies of the input data and the first clock are different, and a selector to supply the frequency phase signal to the feedback loop only in the frequency difference state.

An increase in a data rate of signal transmission and reception inside and outside an apparatus has been desired in relation to the improvement in performance of information processing apparatuses such as an apparatus for trunk communications and a server. A further increase in a bit rate has been desired in, for example, the field of high-speed I/O for transmitting and receiving signals in an integrated circuit chip and between chips (in an apparatus and between apparatuses) and the field of optical communication.
A reception circuit desirably determines transmitted data at an appropriate time and reproduces data and a clock (CDR: clock and data recovery). The CDR is realized by detecting a phase difference and a frequency difference between input data and a reception (sampling) clock and performing, based on information of the phase difference and the frequency difference, phase adjustment of the sampling clock. Among reception circuits, there is known a CDR circuit that retimes input data using a clock reproduced from the input data without using a reference clock and outputs data with reduced jitter.
It is known that the CDR circuit utilizes a phase detection circuit (a phase detector (PD)) that detects a phase difference between the input data and the clock. The CDR circuit using only the phase detector has a problem that a frequency range in which the clock is reproducible is narrow. Therefore, a CDR circuit utilizing a phase-frequency detection (phase frequency detector (PFD)) circuit that detects a frequency relation between the input data and the clock in addition to the phase difference between the input data and the clock is used.
The CDR circuit includes a feedback control circuit including an oscillator having a variable oscillation frequency (e.g., a voltage controlled oscillator (VCO)), a phase-frequency detection circuit, a charge pump (CP), and a loop filter (LPF). The filter LPF is a low pass filter. However, the filter LPF is included in a feedback loop, the filter LPF is called loop filter as well. The phase-frequency detection circuit detects a phase difference and a frequency relation between the input data and the clock and generates a phase difference signal and a frequency phase difference signal. The charge pump and the loop filter perform addition/subtraction of electric currents in accordance with phase difference information and frequency phase difference information and generate a control voltage of the VCO. In other words, the charge pump and the loop filter form a controller of the feedback control circuit. The VCO changes the oscillation frequency in accordance with the control voltage and outputs a clock. The generated clock is supplied to a decision circuit. The decision circuit captures input data in response to the clock, the time of which is adjusted with respect to the input data. The decision circuit may be formed as a part of the phase-frequency detection circuit.
Various phase-frequency detection circuits have been proposed. For example, for high-speed data reception, a differential phase-frequency detection circuit relatively small in circuit size including first and second phase detection circuits and a frequency phase detection circuit is widely used. The first phase detection circuit generates a clock phase control signal based on a phase relation between input data and a first clock. The first phase detection circuit is formed by, for example, two latch circuits, which latch the first clock at a change edge of the input data, and a multiplexer. An output of the multiplexer serves as a clock phase control signal. The second phase detection circuit includes a circuit configuration same as the circuit configuration of the first phase detection circuit and generates a clock phase detection signal based on a phase relation between input data and a second clock. The second clock has a frequency the same as the frequency of the first clock and has a phase different from the phase of the first clock by, for example, 90 degrees. The second clock is outputted from the VCO together with the first clock or is generated by phase-shifting the first clock with a phase shifter.
The frequency-phase detection circuit is formed by two latch circuits, which latch the clock phase detection signal outputted by the second phase detection circuit at a change edge of the clock phase control signal outputted by the first phase detection circuit, and a multiplexer. The multiplexer generates, from a direction of the change edge of the clock phase control signal and a latched value, a frequency phase signal indicating whether the frequency of the first clock is small or large with respect to the frequency of the input data. The frequency phase signal indicates +1 when the frequency of the first clock is small with respect to the frequency of the input data, indicates −1 when the frequency of the first clock is large with respect to the frequency of the input data, and indicates 0 when the frequency of the first clock is the same as the frequency of the input data. The clock phase control signal and the frequency phase signal are supplied to the charge pump. That is, the VCO is controlled based on the clock phase control signal and the frequency phase signal.
When the frequency difference between the input data and the first clock decreases and the input data and the first clock coincide with each other, the frequency phase signal becomes zero and the control of the VCO is not affected by the frequency phase signal. In other words, the VCO is controlled in accordance with only the clock phase control signal and the VCO is controlled to be in a state in which the input data and the first clock have a predetermined phase difference. This state is referred to as a lock state.
Providing a selector that performs switching is also proposed. The selector supplies the frequency phase signal to the charge pump until the frequency phase signal becomes zero and supplies the clock phase control signal to the charge pump after the frequency phase signal reaches a fixed value.
Even in the lock state, during reception of a signal having large jitter, the frequency phase signal may fluctuate and the frequency-phase detection circuit may malfunction and output a clock phase detection signal indicating that the frequencies of the input data and the first clock do not coincide with each other. When such a clock phase detection signal is inputted to the charge pump, the control of the VCO temporarily changes, and a loss-of-synchronization (unlock) error indicating that the frequency of the first clock is different from the frequency of the input data occurs.
In a normal lock state, the CDR circuit is controlled such that one change edge (a falling edge here) of the first clock coincides with a change edge of the input data. However, even when the other change edge (a rising edge) of the first clock coincides with the change edge of the input data, the CDR circuit has a metastable state in which the frequency phase signal is zero, and when the loss-of-synchronization error occurs, the CDR circuit may be in the metastable state.
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication Nos. 11-355111 (hereinafter referred to as Patent Literature 1), 2010-141594, 6-216765, and 2002-135093.
In addition, the related techniques are discussed in Ansgar Pottbacker, et al., "A Si Bipolar Phase and Frequency Detector IC for Clock Extraction up to 8 Gb/s", IEEE Journal of Solid-State Circuits, Vol. 27, No. 12, December 1992 (hereinafter referred to as Non-Patent Literature 1).
Desired is a signal reproduction (CDR) circuit that is synchronization-error free and does not lose synchronization even in a lock state and even during reception of a signal having large jitter.

Signal reproduction circuit, electronic apparatus, and signal reproducing method


Muramyl peptide compounds are useful in the prophylaxis of cancers and particularly in the treatment of precancerous lesions associated with cancers of the mucosa or epithelium.

Cancer is a term which is used to describe the development of abnormal cells which grow in a rapid and uncontrolled manner and are often invasive. The invasion of vital organs frequently results in the death of a patient.
Cancer is extremely widespread and, indeed, it is thought that about 30% of people are likely to contract cancer at some time in their lives with cancer being the cause of death in around 20%. Traditional treatments for cancer include surgery and radiotherapy but, more recently, attention has been turned to the development of chemotherapeutic or cytotoxic agents which can damage or kill cancer cells.
In recent years, increasing attention has been drawn towards the occurrence of tissue changes that are indicative of an increased risk for the subsequent development of particular cancers at that site of change. A variety of these have been described, including modifications of the intestinal wall (intestinal polyps) which are associated with increased incidence of cancers of the colon and rectum, alterations of the skin (actinic keratoses) which are associated with carcinomas of the skin, and condylomata of the cervix, which are associated with cancer of the uterine cervix. To one skilled in the art, these conditions or tissue changes tending to proceed to cancer, to be associated with the development of cancer, or to carry a significant risk of cancer are known as precancerous conditions or lesions. In some cases, the cause of these precancerous conditions is reasonably well established, as in the case of actinic keratoses resulting from excessive exposure to sunlight, or infection with human papilloma virus in the case of condylomata of the cervix (Cancer in Practice by G J G Rees, S E Goodman and J A Bullimore. Pub Butterworth-Heinemann, Oxford, 1993). In other cases, the cause of the precancerous lesion has not been identified.
The present invention relates to the use of certain muramyl peptide compounds (MDPs) in the prophylaxis of cancer and especially in the treatment of precancerous lesions.
It has long been known that non-specific stimulation of the immune system can be brought about by exposure to bacteria, or components extracted from bacterial cells. The specific components responsible for this activity were identified as sugar-containing peptides of the cell wall, and further biochemical analysis of the peptides identified them as the peptidoglycan component of the cell wall. The smallest effective synthetic molecule was found to be an N-acetyl-muramyl-L-alanyl-D-isoglutamine (Merser et al, Biochem. Biophys. Res. Comm. 66 1316 (1975)) which is often referred to as a prototype muramyl dipeptide or prototype MDP.
Subsequently, a wide variety of analogues of prototype muramyl dipeptide were synthesised, some of which have been proposed as treatments for the restoration of immune function or the non-specific stimulation of the immune system. These analogues, and prototype MDP itself are known as muramyl peptide compounds (MDPs).
In the past, some work has been carried out on the use of MDPs in the treatment of cancer and, for example, Key et al, J. Natl. Cancer Inst., 69(5), 1189-1198 (1982) describe the treatment of lung melanoma metastases with liposomes containing an MDP derivative. Later, the same group of workers investigated the optimal conditions and limitations for the eradication of melanoma metastases using a liposome encapsulated MDP derivative, MTP-PE (Fidler et al, Cancer Imnunol. Inmmunother., 21(3) 169-173 (1986)). In addition it was found that orally administered non-liposome encapsulated MTP-PE produced tumouricidal activity in both lung and peritoneal macrophages and was effective in inhibiting lung and lymph node metastasis although it was not effective in eradicating well established melanoma metastases (Fidler et al, J. Immunol., 138(12), 4509-4514 (1987)).
Phillips et al, J. Biol. Response Modif., 6(6), 678-691 also describe work relating to the treatment of experimental pulmonary metastases using liposomes containing lipophilic MDP analogues. Again, the compounds were used to treat experimentally induced pulmonary B16 melanoma tumours in mice. However, Kleinerman et al in J. Clin. Oncology, 9(2), 259-267 (1991) concluded that it is unlikely that the MDP derivative L-MTP-PE can serve as a single modality in treating metastatic disease.
Some MDPs have been used in clinical trials for human therapy. For example, Kleinerman et al (Kleinerman, E S, Cancer Immunol. Immunother, 34: 211-220, 1992) have used a lipophilic analogue in a liposomal formulation in the treatment of lung metastases developed in patients with osteosarcoma.


A device for mechanically checking the growth of noxious weeds within the growing containers of potted plants is shown. The device includes a mat of porous construction adapted to fit within the open top of a pot and engage a side wall thereof for inhibiting weed growth by shading the pot interior from light. A retainer, for positioning atop the mat, frictionally engages a side wall of the pot and retains the mat securely within the open top thereof. The pot may be provided with an overhanging and inwardly directed lip proximate the top of its side wall for engaging the retainer and locking such in place. In an alternative embodiment of the device, the retainer is formed as a ring, having an inverted U-shaped cross section, integrally joined to the outer edge of the mat for frictionally securing the mat to the pot. The device may also be provided with one or more chemical treatments such as herbicides, insecticides, fungicides, and fertilizers for promoting the growth of specified plant materials.

Of the plant materials grown for sale, transplanting, or experimentation by commercial landscape nurseries, the majority are now developed in containers on top of the ground surface. Container grown plant materials are known for their high survival rates and low production costs. The containers, usually filled with an admixture of soils and plant nutrients, provide an ideal environment for rapid plant growth. In addition to collecting water and retarding evaporation, the containers shield the plant roots from animal attack, provide some insulation from temperature extremes, and furnish a means for readily moving the plant material from place to place without resort to time consuming and manpower intensive digging or trenching activities.
Despite the best efforts of many nurserymen, contaminated soil mixtures, wind, and animals contribute to the addition of unwanted plants to nursery stock growing containers. Weeds deposited in these containers thrive and, if left unchecked, have a tendency to smother their more valuable neighbors. Weeds not only reduce the amount of sunlight reaching the desired plant materials, slowing their growth rates, but rob the soil of essential nutrients critical to plant development.
Commercial nurserymen have attempted to control the growth of weeds which may develop in containers; however, not with any particular success. Isolation of containers and growing media from weed sources, especially in large scale nursery operations, has been found to be impractical. Physically removing weeds as they sprout is highly labor intensive and inefficient. Therefore, many growers have resorted to the use of costly chemical herbicides for controlling weed growth in their planting containers.
Samples of air, soil, and water taken from locations remote from nurseries which have utilized chemical herbicides over time have included trace amounts of such herbicides. Although the herbicides employed in the United States have been subjected to stringent regulatory testing and approval, the long-term effects on man and the environment are, as yet, unknown. Limiting exposure to such toxic chemicals, however, seems reasonable, and any reduction in the amount of these chemicals leaching from the area of their intended use would undoubtedly be highly beneficial.
Heretofore, the use of mechanical weed barriers, capable of controlling weed growth without large investitures in terms of manpower or chemical herbicides, has been restricted to the use resilient sheets for covering large areas of ground surface. Some of these so-called agrotextile sheets are known to have porous structures permeable to water and air while others are of flexible and impermeable plastic having a closed structure. While the permeable sheets permit water to pass into the ground limiting surface runoff, their interconnected pore spaces are generally so small as to prevent most growing plant shoots from passing therethrough. Furthermore, many agrotextile materials prevent the passage of light thereby inhibiting the growth of plants having the agrotextile placed between such and a light source. The use of such materials in applications involving plant growing containers is believed to be novel and would be greatly beneficial to many nurserymen who would find it desirable to have a device which would control weeds with a minimal use of expensive herbicides, often ineffective for their intended purposes, difficult to apply, and potentially harmful to the environment.


A device for generating electromagnetic oscillations in the HF range, in particular in the gigahertz range, using at least one Gunn element, in particular at least one Gunn diode. The device is designed to be attached to at least one printed-board-like electric or electronic circuit configuration, in particular an electric or electronic HF circuit configuration, having a generally planar expansion.

In high-frequency circuits and extra-high frequency circuits (frequency f higher than fifty gigahertz), Gunn elements are used for generating the electromagnetic oscillations. Such Gunn elements may be situated in a housing (see, German Application No. DE 199 06 205 A1).
Gunn oscillators are used as HF sources at, for example, 77 gigahertz in applications in vehicle radar units for distance detection and distance regulation. In conventional designs, these Gunn oscillators are connected via a screwable hollow conductor connection to suitable transitions (known as step-transformers), which feed the high-frequency energy into planar distribution networks. The feed of the supply direct voltage takes place as a rule via a manually soldered cable joint.
In this type of transition, however, at least one flanged joint including screw connection and dowel pins is provided which makes the device costly and cumbersome to mount; in addition, the voltage lead wire must be soldered separately according to the related art, and finally, arranged suppression capacitors conventionally require an additional printed board.

Device for generating oscillations in the high frequency range


A metal canopy structure, including: arches arranged in parallel formation, equally spaced apart, the arches having a planar construction and disposed on a plane running along a first axis; a plurality of cross beams arranged in parallel formation and disposed on a second axis perpendicular to the first axis and mechanically coupled to the plurality of arches; a plurality of support poles, each of the arches mechanically coupled to a pair of support poles; a plurality of coupling poles, the coupling poles disposed along the second axis and mechanically coupled to the plurality of support poles, at least a portion of the coupling poles arranged in a parallel formation.

Almost all steel structures suffer from inadequacies during assembly. Similar pieces are bought in bulk and cut to size, bent to shape and welded in place as necessary. The on-location activities extend the assembly period, necessitate additional manpower and man hours of work and are wasteful of the building materials. Furthermore, galvanized steel is protected by the elements as a result of the galvanization process. However, the galvanized pieces are generally subjected to on-location changes (cutting, bending, welding, etc.), most of which ruin the weather-proof seal of the galvanization. As a result, the assembled pieces look dirty, scorched and defaced as well as suffering from early corrosion at the joins, seams and welding points.


A Multicall telephony system has a first land-line telephone connected to a central switch in a land-line telephone network and a server executing SW on a processor from a non-transitory medium, the server also coupled to the land-line telephone system by a service telephone number. In operation a user dials the service telephone number, and when connected, dials two or more telephone numbers separated by delimiters and followed by a terminator character, and the server, executing the software, dials the two or more telephone numbers separated by delimiters in the call from the first land-line telephone, and connects answered calls in a conference with the call placed by the first land-line telephone.

1. Field of the Invention
This invention is in the technical area of telephony, and pertains more particularly to enabling multiple calls with a single initiation.
2. Description of Related Art
In current art a telephone essentially allows one person to call another. It is a one-to-one communication instrument. Bust most interactions today require more than two people in the conversation, be it going to lunch with friends or a family dinner or a business conference.
There are indeed conferencing systems well-known in the art, wherein a plurality of persons may be connected, but these do not serve the purpose of a situation where a person might wish to communicate quickly with the same group of people in the same manner of calling one person.
What is clearly needed is a system wherein a person may call a plurality of people in one call by a system of hardware and software.


A gerotor motor (11) of the valve-in in-star type is provided wherein a stationary valve member (17) is disposed immediately adjacent the gerotor gear set (19). The stationary valve member defines a shuttle bore (81) and disposed therein is a shuttle member (107) which moves between two operating positions (FIGS. 6 and 7) under the influence of system pressure. The shuttle valve member (107) communicates system pressure from whichever of the ports (39 or 41) is at high pressure to a pressure balancing recess (63). At the same time, the shuttle valve (107) provides fluid communication between whichever of the ports is at low pressure and a low pressure passage (83) which may be in communication with a lubrication circuit (95), or may be in communication with a case drain port, to divert a small amount of fluid to a heat exchanger. The invention provides a very small shuttle valve arrangement comprising only a single part, and eliminating a substantial amount of the machining previously required in the motor endcap (15).

the present invention relates to rotary fluid pressure devices, and more particularly, to such devices of the type which typically include a gerotor gear set, and a stationary valve member disposed adjacent the gerotor gear set.
Rotary fluid pressure devices which include a gerotor gear set as the fluid displacement mechanism are typically used as low-speed, high-torque motors. Such gerotor motors have traditionally been classified as being either of the "spool valve" type, or of the "disc valve" type. In a spool valve gerotor motor, the valving is accomplished at a cylindrical interface between a spool valve and a surrounding housing. In a disc valve type, the valving is accomplished at a flat, transverse planar interface of a disc valve and a stationary valve member.
More recently, a particular type of disc valve motor has been developed which is sometimes referred to as a "valve-in-star" motor. In this type of motor, a disc valve element is recessed within one axial end face of the gerotor star, and the valving action occurs between the axial end surface of the star and disc valve and the adjacent surface of a stationary valve member. Such valve-in-star motors are illustrated and described in U.S. Pat. Nos. 4,715,798; 4,741,681; 4,756,676; and 4,976,594, all of which are assigned to the assignee of the present invention and incorporated herein by reference.
It should be understood by those skilled in the art that, although the present invention is not limited to use in rotary fluid pressure devices of the valve-in-star type, the invention is especially suited for use in conjunction with such devices, and will be described in connection therewith.
Many gerotor motors of the type sold commercially by the assignee of the present invention include some sort of shuttle valve. In some motors, the only purpose for the shuttle valve is to communicate a relatively small flow of fluid from the low pressure side (downstream of the gerotor) of the motor to a case drain port, from where the fluid flows through a heat exchanger, to prevent overheating of the system fluid. Such shuttle valves are typically located in the endcap casting which defines the inlet and outlet ports of the motor. A typical shuttle valve of the type and for the purpose described above, and which is in commercial usage by the assignee of the present invention is illustrated and described in U.S. Pat. No. 4,343,601, assigned to the assignee of the present invention and incorporated herein by reference.
In some gerotor motors, a shuttle valve arrangement is included to divert a relatively small lubricant flow from the main flow path, and direct the lubricant flow through various parts of the motor which need lubrication, such as spline connections and bearings. An example of a gerotor motor including a shuttle valve used to divert lubricant flow is illustrated and described in U.S. Pat. No. 4,645,438, assigned to the assignee of the present invention and incorporated herein by reference.
Finally, in gerotor motors of the valve-in-star type, in which there is a stationary valve plate disposed adjacent the gerotor, the side of the stationary valve plate axially opposite the gerotor typically defines a pressure balancing region, as is illustrated and described in above-incorporated U.S. Pat. No. 4,976,594. In such motors, assuming bi-directional operation is desired, it is necessary to provide some means to communicate system pressure (the pressure at the inlet port of a motor) to the pressure balancing region, in order to bias the stationary valve member into sealing engagement with the adjacent surface of the gerotor and valve-in-star. This is done to reduce leakage along the face of the gerotor and improve volumetric efficiency of the motor.
In motors of the type shown in above-incorporated U.S. Pat. No. 4,976,594, the shuttle valve has been disposed in the endcap casting, and has typically included the assembly of spools, poppet members, sleeves, springs, and plug members illustrated and described in above-incorporated U.S. Pat. No. 4,343,601. Although such shuttle valve arrangements have generally performed satisfactorily for the intended purpose, the substantial number of parts in the shuttle assembly, and the extra machining required in the endcap casting has added substantially to the size, complexity, and expense of the entire endcap assembly, thus increasing the overall size, weight, and expense of the entire motor.
In addition, the use in valve-in-star motors of the type of shuttle arrangement illustrated and described in above-incorporated U.S. Pat. No. 4,343,601 has been used only to provide low pressure fluid to the lubrication circuit, and from there the fluid flows to a case drain, and then to the system cooler. Communicating high pressure fluid to the pressure balancing region has required additional structure.

Rotary fluid pressure device and improved shuttle arrangement therefor


An aspect of the present invention provides multiple switches in a transceiver, which enable pins provided for transmission and reception to be connected to either a transmit port or a receive port, as desired during operation. As a result, the transceiver can be auto-configured to connect the specific pin, on which signals are being received, to the receive port. Similarly, the transceiver can be auto-configured to connect the specific pin, on which the signals need to be transmitted, to the transmit port. Various design considerations in providing such switches are also described.

1. Field of the Invention
The present invention relates to transceivers used in Ethernet type cable based networks, and more specifically to a method and apparatus which enables auto-configuration of such transceivers to connect transmit and receive ports to corresponding ports on the other end irrespective of cable connection mis_match.
2. Related Art
Devices often contain transceivers (hereafter "transceivers") which transmit and receive signals on different paths (hereafter cables). To facilitate such transmission and reception, each transceiver generally contains a receive pin and a transmit pin. Thus, the receive pin is connected to one cable ("receive cable" merely for explanation) and the transmit pin is connected to another cable ("transmit cable").
Transceivers generally also contain a transmit port on which an internal circuit (transmit circuit) makes the signal available for transmission, and a receive port on which another internal circuit (receive circuit) receives a signal received from external sources.
In one prior approach, the transmit pin(s) and receive pin are respectively hardwired to the transmit port and the receive port, and a user is accordingly required to accurately (manually) connect the transmit cable to the transmit pin and the receive cable to the receive pin. A cable connection mis-match is said to occur when the receive pin is connected to the transmit cable, and the transmit pin is connected to the receive cable.
A cable connection mis-match may be undesirable for several reasons. For example, in the case of Ethernet twisted pair cables connecting two devices (e.g., two repeaters or network interface card with a repeater) according to the above-noted prior approach, the transmit pin of one device is to be connected to the receive pin of the device at the other end by a cable. A mis-match may render the two devices non-operational, at least until the connections are switched.
Accordingly, at least to reduce the complexity of deploying the devices, there has been a generally felt need to auto-configure transceivers such that transceivers would be operable irrespective of the connection of the cables to the pins. In other words, the internal implementation within a transceiver would be automatically (re)configured in case of a wrong connection, to automatically (without manually switching the cables) cause the devices to communicate.
In one prior auto-configuration approach, substantial portion of the transmit and receive circuits are replicated at each pin and only either transmit or receive circuit is used at a pin (at a given time instance) depending on the cable connected. One problem with such an approach is increased area requirements and possibly additional exposure to failure due to the increased number of components. At least for such reasons, the prior auto-configuration approach may not suitable in several environments.
What is therefore required is an improved method and apparatus which enables auto-configuration of such transceivers to connect transmit and receive ports to corresponding ports on the other end irrespective of cable connection mis_match.

Auto-configuration to connect transmit and receive ports to corresponding ports on the other end irrespective of cable connection mis-match


A tubing holding device for a roller pump is disclosed. The tubing holding device is removable from the roller pump, slidably moveable and able to be opened to allow for easy exchange of tubing in roller pumps. The tubing holding device comprises a clamping mechanism that securely holds tubing in place. Tubing of various sizes may be used within a roller pump by selecting the appropriately sized tubing holding device, or by using a tubing holding device, such as one embodiment disclosed, which may be adjustable for different sizes of tubing. Roller pumps including the tubing holding devices, and methods of loading such roller pumps are also disclosed.

Roller pumps have many uses in the medical field. For example, roller pumps are used as blood pumps during hemodialysis or cardiopulmonary bypass. Generally, medical roller pumps consist of a pump head and a pump drive, with the pump head comprising a pump stator and a pump rotor. The pump stator is essentially a hollow chamber having a surface against which one or more hoses or tubing are compressed by the pump rotor. The pump rotor, which is rotatable about its longitudinal axis, is arranged in the pump stator in such a manner that the pump rotor engages tubing positioned in the pump stator with two or more rollers. On rotation of the pump rotor, the rollers compress the tubing as they are rolled along the tubing. A fluid medium contained in the tubing is then transported in a direction of the pump rotor rotation. In order to deter the tubing from wandering within the pump stator while under the influence of the rollers, one or more ends of tubing sections entering and exiting the pump stator are typically fastened in place relative to the pump stator. For roller pumps with reversible running direction, it is usual to provide a fastening at both ends of the tubing within the pump stator.
In some roller pumps, fastening means for holding tubing in place in a pump stator are inserts that latch together to hold the tubing and are screwed into place on the pump stator. The inserts come in many different sizes, each for one size of tubing. The disadvantage of using such fastening inserts is that they need to be screwed out and back in for each necessary tubing size change, which is not efficient.
Another tubing fastening arrangement for a roller pump is described in U.S. Pat. No. 5,533,877. The described fastening arrangement is a detachable piece from a pump head that includes two individual fasteners for attaching two sections of tubing. The detachable piece, including both individual fasteners, has grooves that are slid on proturbances on the pump head to allow for detachment and reattachment of the whole detachable piece. In order to change the tubing in the detachable piece, the detachable piece must be completely removed from the pump head.
Thus, it is desirable to have a tubing holding device for a roller pump that enables easy exchange of tubing configurations in the roller pump.


A connector assembly comprising a connector housing, a secondary locking member and a safety spring bar, whereby the secondary locking member and the safety spring bar are assigned to the connector housing. The secondary locking member is movable between a first and a second position, whereby the safety spring bar is adapted to lock the secondary locking member in its second position. The secondary locking member comprises a deflection surface adapted to engage the safety spring bar when the secondary locking member is moved in an insertion direction. Thereby, upon movement of the secondary locking member, the safety spring bar is deflected essentially in the insertion direction, urging the secondary locking member towards its first position. When the secondary locking member is placed in the second position, the safety spring bar is adapted to snap into a safety position, to lock the secondary locking member in its second position.

In many applications, the save coupling of connectors is of high importance. For example, in the case of car safety systems, as e.g. airbag systems in passenger cars, the connectors used for the connection of an airbag to its ignition base have to be provided with reliable safety systems. To ensure that the connectors cannot become loose unintentionally, secondary locking members are used to guarantee the save mechanical coupling.
An example of a connector with a secondary locking member is described in the WO 97/41623 A1. This document describes a connector which can be mated with a corresponding counter connector being part of an airbag ignition mechanism. In assembled condition, when the connector is mated with the corresponding counter connector, it is fixed to the counter connector by means of flexible latching arms. During mating of the connectors, these arms are deflected and snap back into corresponding latching clearances of the counter connector, when fully mated. For securing the mechanical coupling of the connectors, the WO'623 suggests a secondary locking member which can be inserted into the connector when the two connectors are mated. The secondary locking member comprises locking arms, which upon insertion of the secondary locking member move between faces of the counter connector housing and the latching arms of the connector. Once the locking arms are inserted, they inhibit bending of the latching arms. Thus, the latching arms cannot bend out of the latching clearances and the mechanical coupling of the connectors is secure. The secondary locking member described in WO'623 is further provided with locking means to fix the secondary locking member in its locking position, which is the above described position in which it secures the connector mating. However, in the case described in the WO'623, it is possible to place the secondary locking member in a half-fitting position, in which it may not function properly and in which it is not fixed to the connector, and therefore can be removed unintentionally.
A further development of a secondary locking member is disclosed in the co-owned patent application DE 100 05 858 A1. This document discloses a connector with a secondary locking device and a safety spring element, which serves to hold the secondary locking member in a pre-locked position, in which the secondary locking member is mounted to the connector housing but does not hinder mating or unmating of the connector with a corresponding counter connector. The safety spring element described in the DE'858 further provides a so-called go/no go function for the secondary locking member: In the pre-locked position of the secondary locking member, two spring arms of the safety spring element are in contact with stop shoulders of the secondary locking member, thereby preventing a movement of the secondary locking member in direction towards its locking position. Upon mounting of the connector to a corresponding counter connector, the counter connector housing comes into contact with a releasing portion of the connector housing, thereby pressing this releasing portion against the safety spring element. By this pressing action, the safety spring element is deformed and the two spring arms are freed from the stop shoulders of the secondary locking member. Upon consequent moving of the secondary locking member towards its locking position, each spring arm is guided by an inclined channel of the secondary locking member, thereby being bent and biased against the edge of this inclined channel. Shortly before the secondary locking member is placed in its locking position, each spring arm passes a turning point of the inclined channel and snaps into a notch of the secondary locking member, thereby fixing the secondary locking member in its locking position. As long as the secondary locking member is not placed in this locking position, the spring arms are biased against the edges of the inclined channel, and due to the resulting restoring spring force they inhibit the secondary locking member to be placed in a half-fitting position unintentionally: i.e. the spring force causes the secondary locking member to move back into its pre-locked position. The safety spring element thereby provides a go/no go mechanism for the secondary locking member, which assures that the secondary locking member is either placed correctly in its locking position or is moved back into its pre-locked position, but prevents any intermediate position.
It is an object of the present invention to improve the state of the art by providing a connector assembly with an improved secondary locking mechanism. It is in particular an object of the present invention to provide a connector assembly with a secondary locking member which is provided with an improved and more reliable go/no go mechanism, which does not become non-serviceable, e.g. due to fatigue damage of spring components. It is an even further object of the present invention to accomplish said tasks by providing an inexpensive and non-complex secondary locking member, which preferably can be produced as an injection molded part. These and other objects which become apparent upon reading the following description are solved by a connector assembly according to claim 1.

Connector assembly with safety spring bar

Delphi International Operations Luxembourg


A device for precise cutting of imitation stone. An upper blade is mounted to an upper blade mount assembly for vertical sliding movement over a stationary lower blade. Downward movement of a handle rotates a cam surface that engages a convex upper surface of the upper blade mount assembly. This action moves the upper blade into contact with a piece of imitation stone disposed between the upper and lower blades, and further lowering of the upper blade then cuts the stone. The cutting edge of each of the blades is beveled on one side only such that each of the blade edges is asymmetrical in vertical cross-section.

1. Field of the Invention
This invention relates to devices for cutting stone accurately to shape, and more particularly for cutting imitation stone at a building construction site for use in bathroom and kitchen counters, floors, walls, fireplaces, patios, cobblestone walkways, and for a variety of other applications.
2. Description of Related Art
Natural stone is a highly desired construction material, but its use entails high labor and shipping costs. Imitation stone, also known as manufactured stone, has been used for over thirty years and is commonly substituted for natural stone because of its low shipping and installation cost, high quality, and low weight. Imitation stone is made from poured concrete, pumice, and special high-quality, long-lasting permanent pigments. Imitation stone is typically adhered to a wall surface with a cement stucco mixture that is often very rich in Portland cement; in contrast, natural stones are set on top of one another. It is usually necessary to trim and shape imitation stones preparatory to their installation in a wall or other setting.
Prior to my invention, there existed no satisfactory cutting device for imitation stone. Stone and tile cutting devices that require a percussive blow were disclosed in U.S. Pat. No. 3,886,927 to Chattin and U.S. Pat. No. 812,973 to Barr et al., respectively, but a percussive blow risks shattering imitation stone. U.S. Pat. No. 600,856 to Brinkman disclosed a tile cutting machine that used a movable upper and a fixed lower blade aligned in a cutting plane, each blade having serrated teeth, wherein the upper blade was movable between a pair of upright standards and actuated by means of toggles by movement of a hand lever. I have found, however, that one obtains a more precise and even cut of imitation stone if the upper and lower blades each have a smooth edge instead of a serrated edge, and if the edges are asymmetrical in vertical cross-section and are oppositely canted with respect to the cutting plane, as explained below. U.S. Pat. No. 2,053,043 to Patterson disclosed a stone cutting machine that employed a crank disk to actuate movement of an upper blade by means of toggles; the cutting edges of the upper and lower blade were V-shaped—that is, each blade edge was symmetrical in vertical cross-section. U.S. Pat. No. 6,079,304 to Bisceglia disclosed a pinch blade tool, intended for trimming shingles, having a stationary blade and a movable blade that moved with a sliding action to pinch work between the blades, but did not teach the use of asymmetrical blade edges.
My cutter employs a single pair of apposed cam surfaces for imparting, by downward movement of a handle, a gradual and uniform downward cutting motion to an upper blade thereof. U.S. Pat. No. 1,805,163 to Buckner disclosed a belt cutter that had two, laterally spaced-apart pairs of apposed cam surfaces, linked for unitary motion by a connecting link, for moving an upper, cutting blade downward through a work piece (belt). U.S. Pat. No. 2,626,664 to Regele also employed a dual cam drive in combination with an upper blade that was inclined with respect to the lower blade; the upper blade simultaneously descended and swung lengthwise the lower blade to achieve a progressive cut. Dual cam drives, such as those of Buckner and Regele, are unnecessarily complex and expensive for an imitation stone cutter. A single cam drive in combination with my improved blade edges provides a simpler, less expensive and more robust cutter.


An integrated measurement device for taking gauge and cross-level measurements between two objects. The integrated measurement device includes at least an emitter/receiver unit, a sensor unit, and a microprocessor. In operation, the integrated measurement device is pivotably placed on the top of the first object such that a light emitted from the emitter/receiver unit travels along a surface of the second object as the device rotates about a pivot point of the first object. The sensor unit senses data associated with incident angles and traveling distances of the emitted light. Based on the data sensed by the sensor unit, the microprocessor calculates the incident angle, the traveling distance, and a distance between the first and second objects. The calculated values can also be transformed to (x, y) space coordinates that are used to describe a profile of the second object.

1. Field of the Invention
The present invention relates to a laser gauge and cross-level sensor apparatus, and more particularly, to an integrated measurement device for obtaining positional information associated with two objects.
2. Background of the Invention
Laser gauges and cross-levels are commonly used in the railroad industry for measuring geometrical characteristics of railroad tracks. The laser gauges have been developed for some time to facilitate railroad track alignment and/or track profile measurement. The laser gauges, which are used to measure the distance between the rails (gauge), can be mounted upon a railroad car and propelled along the track to be inspected. The laser gauges are operated to accurately sense track defects, variations in track profile and other track irregularities, which might result in dangerous condition. In addition to the laser gauges, cross-level sensors can be used to detect relative level differences which might result in rocking and ultimate derailment of a railroad car.
Typically, operators utilize separate laser gauges and cross-level sensors for the measurement of the railroad track. The most-commonly used cross-level sensors are solid bars connecting the left and the second rails. The bars are about 59-inch long, which can be barely fitted into the trunk of a car. Therefore, most people carry a tape measure instead of the gauge and ignore the cross-level measuring.
Accordingly, there is a need for an integrated unit that includes laser gauge and cross-level. Preferably, the integrated unit is a handheld device that is compact enough to be carried by users in a pocket.


A composition of L-ascorbic acid derivatives is described comprising L-ascorbic acid and lysine or lysine moieties, wherein L-ascorbic acid is covalently bound to the lysine or lysine moieties. The composition so described is used to prevent the degradation of extracellular matrix, stabilize connective tissue, is used to as an antioxident, and is used for treating damage to skin comprising applying the topical composition to the skin.

L-Ascorbic acid, also known as vitamin C, is an important dietary factor. It is not synthesized in vivo in human, monkey and guinea pig and therefore is listed as an essential nutritive element. This ubiquitous compound is essential for the maintenance and preservation of several species including human being. Scurvy has been known as a condition due to deficiency of L-ascorbic acid and is marked by weakness of the skin, petechial hemorrhage, ecchymosis, and hemorrhages in the gingiva and marrow, which can be life threatening. To prevent scurvy for the maintenance of health, a recommended daily administration is established for L-ascorbic acid; in particular, 60 mg for adult male and 50 mg for adult female.
L-ascorbic acid is probably the most effective, efficient and least toxic antioxidant. It is a water soluble, chain-breaking antioxidant. The mechanism of action involves L-ascorbic acid acting as scavenger for harmful radicals like superoxide, hydroxyl and singlet oxygen that are produced during normal or pathological cellular metabolism. Ascorbic acid is speculated to be superior to other water soluble and lipid soluble antioxidants. It also protects DNA, enzyme, protein and lipids from oxidative damage and thereby prevents aging, coronary heart diseases, cataract formation, degenerative diseases and cancer. Oxygen radicals have been implicated not only in initiation and post-initiation stages of carcinogenesis, but also in invasion and metastatic processes.
L-Ascorbic acid takes part in several important physiological functions in vivo. It is essential for collagen synthesis, proteoglygans and various components of extra cellular matrix (ECM). It helps to maintain various enzymes in their reduced forms. L-Ascorbic acid is involved in the hydroxylation of lysine and proline to the formation of hydroxylysine and hydroxproline which are necessary for the synthesis of collagen in living connective tissues. These reactions are mediated by lysly hydroxylase and prolyl hydroxylase for which L-ascorbic acid functions as cofactor. Lysine and proline are principal components of tendons, ligaments, skin, bone, teeth, cartilage, heart valves, cornea, eye lens and ground substances between cells. Hydroxproline and hydroxlysine are required for the formation of a stable ECM and cross link in the fibers. Any deficiency of L-ascorbic acid reduces the activity of prolyl hydroxylase and lysyl hydroxylase. This results in impaired formation of collagen which leads to tissue weakness and eventually, scurvy.
Medicine considers L-ascorbic acid and lysine as one of the most important natural substances that is indispensable for maintenance of health at the cellular level. Deficiency of these substances in humans may lead to various diseases. Almost all diseases are a culmination of a lack of L-ascorbic acid and lysine. Lysine inhibits the destruction of collagen molecules by binding with plasminogen and thus preventing its breakdown to plasmin, which is one of the enzymes responsible for breakdown of collagen and for activating other matrix metallo proteinases (MMPs). Since our body cannot produce its own lysine, it has to be supplied through diet or from dietary supplements. Another important amino acid, Proline, is presumed to be synthesized in the body in adequate quantities for normal functions. It is likely that under stress conditions the quantity synthesized falls short of the body needs. This often leads to a conditioned deficiency of this important amino acid.
Another hydroxproline containing protein is the plasma complement component Clq, which constitutes an integral part of the protective mechanism against pathogens. The concentration of Clq is significantly reduced in guinea pigs fed a ascorbic acid deficient diet. In addition, L-ascorbic acid participates in the biosynthesis of carnitine and neuroendocrine peptides.
L-Ascorbic acid has several reactive hydroxy groups that can be used for the synthesis of a number of derivatives. Many substituted compounds at 2-, 3-, 5- and 6-positions have been synthesized. L-ascorbate 2-sulphate is stored in fish and some shrimp. It has the L-ascorbic acid activity for fish such as trout, salmon and catfish. It is 20 times more stable than ascorbic acid. Hence, it has been used in the formulation of feeds. L-ascorbate 2-phosphate is more stable in air than ascorbic acid. This compound is used as source of L-ascorbic acid in guinea pigs and rhesus monkeys. L-ascorbyl 6-palmitate, a synthetic lipophilic ascorbic acid derivative, is another effective preservative in foods and pharmaceuticals.
In recent years there has been a growing interest in the therapeutic application of L-ascorbic acid and its derivatives as an anti-cancer agent.

Ascorbic acid compounds, methods of synthesis and application use thereof


A one-part cold crosslinking emulsion composition containing, in an aqueous medium, a double-structure fine grain comprising the following Component (A) 1 and the following Component (B) 2 covering the same, wherein the following Component (C) is contained in Component (B) 2:. (A) a copolymer comprising an epoxy group-containing monomer and an ethylenic unsaturated monomer; PA1 (B) a copolymer comprising an unsaturated carboxylic acid and an ethylenic unsaturated monomer; and PA1 (C) a low molecular weight monofunctional epoxy compound.

The present invention relates to a one-part cold crosslinking emulsion composition employed in the fields such as coatings, adhesives, fiber processing, civil engineering and the like and a method of manufacturing the same.
Since aqueous emulsions in general are superior in terms of safety and hygiene to solvent type resins, they are widely used in the fields such as coatings, adhesives, fiber processing, civil engineering and the like. However, films using aqueous emulsion have problems of inferiority in water resistance, permeability to base material, impregnation-reinforcing property, surface smoothness and the like to films using the solvent type resins. Hence, in order to improve such aqueous emulsions, a method has been proposed of enhancing permeability to base material and surface smoothness by lowering a molecular weight of polymers so as to produce fluidity and achieving good water resistance and impregnation-reinforcing property by crosslinking the polymers after film formation. For example, an aqueous emulsion has been proposed in which fine grains of a double structure (a core-shell structure), having a core part in which glycidyl group-containing monomers are polymerized and a shell layer in which carboxyl group-containing monomers are polymerized and a shell layer in which carboxyl group-containing monomers are polymerized, are contained in an aqueous medium and, after film formation, glycidyl groups and carboxyl groups are subjected to crosslinking reactions (Japanese Patent Publication No. 39025/88). In the meantime, another aqueous emulsion has been proposed in which amino group-containing monomers are used instead of the above-mentioned carboxyl group-containing monomers, and, after film formation, glycidyl groups and amino groups are subjected to crosslinking reactions (Japanese Provisional Patent Publication No. 73308/94).
Regarding the above-described aqeuous emulsions, however, there is a fear that crosslinking functional groups (glycidyl groups, carboxyl group and the like) existing inside the fine grains will crosslink each other at storage. In particular, such tendency is prominent in case of storage under a high temperature. For this reason, the molecular weight of the fine grains increases during the storage of the aqueous emulsions and fluidity deteriorates. As a result, films using such aqueous emulsions have disadvantages of poor permeability to base material and surface smoothness.
It is an object of the present invention to provide a one-part cold crosslinking emulsion composition which exhibits excellent storage stability with maintaining good crosslinking property and a method of manufacturing the same.

One-part cold crosslinking emulsion composition and method of manufacturing the same

National Starch and Chemical Investment Holding Corporation


A method for determining a with-distance relationship between a first geometry object and a second geometry object. The method includes defining an exterior approximation of the first geometry and the second geometry. A distance between the exterior approximations is computed. The computed distance is compared with a first predetermined distance to determine whether the second geometry satisfies a first filter condition with respect to the first geometry.

Information in databases may be organized according to any number of techniques. Examples of the many database indexes include the quadtree, the B-tree, and the R-tree. Different database index structures may be more suitable for particular types of data. For example, some database index structures, such as B+trees, may not be suited for multi-dimensional data.
The R-tree is an object hierarchy that is applicable to arbitrary spatial objects that is formed by aggregating minimum bounding boxes for the spatial objects and storing the aggregates in a tree structure. The aggregation is based, in part, on proximity of the objects or bounding boxes. Each node in the tree represents a region in the space. Its children represent (possibly overlapping) subregions. The child regions do not need to cover the entire parent region. While the R-tree is designed primarily for storing region objects, it can be adapted to points by defining points as "degenerate" rectangles where all vertices are identical.
The number of objects or bounding boxes that are aggregated in each node is permitted to range between m≦(M/2) and M, thereby leading to use of the prefix (m,M) to characterize a particular R-tree and mirroring the effect of a B-tree. The root node in an R-tree has at least two entries unless it is a leaf node, in which case it has just one entry corresponding to the bounding box of an object. The tree is height-balanced (with maximum height logmr).
An R-tree can be constructed in either a dynamic or a static manner. Dynamic methods build the R-tree as the objects are encountered, while static methods wait until all the objects have been input before building the tree. The results of the static methods are usually characterized as being packed since knowing all of the data in advance permits each R-tree node to be filled to its capacity.
There are two principal methods of determining how to fill each R-tree node. The most natural method is to take the space occupied by the objects into account when deciding which ones to aggregate. An alternative is to order the objects prior to performing the aggregation. However, in this case, once an order has been established, there is not really a choice as to which objects (or bounding boxes) are being aggregated. One order preserves the order in which the objects were initially encountered. That is, the objects in aggregate i have been encountered before those in aggregate i+1.
According to one method, insertion of a region object R occurs as follows. Starting at root, children that completely contain R are identified. If no child completely contains R, one of the children is chosen and expanded so that it does contain R. If several children contain R, one is chosen and the process proceeds to the next child.
The above containment search is repeated with children of the current node. Once a leaf node is reached, R is inserted if there is room. If no room exists in the leaf, it is replaced by two leaves. Existing objects are partitioned between two leaves and parent. If no room exists in the parent, change propagates upward.
One difference between static and dynamic methods is that static methods rebuild the entire R-tree as each new object is added. In contrast, dynamic methods add the new objects to the existing R-tree. Dynamic methods differ in the techniques used to split an overflowing node during insertion.
There are two types of dynamic methods. The first type has the goal of minimizing coverage and overlap. These goals are at times contradictory and thus heuristics are often used. The second type makes use of the ordering applied to the objects (actually their bounding boxes). They are termed nonpacked. In this case, the result is equivalent to a B+-tree and all update algorithms are B+-tree algorithms. These update algorithms do not make use of the spatial extent of the bounding boxes to determine how to split a node. Thus, the goals of minimizing overlap or coverage are not part of the node splitting process although this does not preclude these methods from having good behavior with respect to these goals.
Static methods differ on the basis of the method used to order the objects. The dynamic methods that are not based on an ordering, that is, reduction of coverage and overlap, range from being quite simple, for example, exhaustive search, to being fairly complicated, for example, R*-tree. Some method just split the overflowing node, while others, that is, the R*-tree, try to reinsert some of the objects and nodes from the overflowing nodes thereby striving for better overall behavior (e.g., reduction in coverage and overlap).
In general, the goal of splitting techniques is to minimize coverage and overlap. These goals are at times contradictory and, thus, heuristics are often used. Below are listed a few node splitting algorithms that range from being quite simple, for example, exhaustive search, to being fairly complicated, for example, R*-tree. Some methods split the overflowing node, while others try to reinsert some of the objects and nodes from the overflowing nodes, thereby striving for better overall behavior, for example, reduction in coverage and overlap.
A number of different node splitting algorithms may be tried, including:                I. Dynamic methods based on minimizing coverage and/or overlap                    1. Exhaustive search            2. Quadratic method            3. Linear method            4. R*-tree            5. Ang/Tan method                        II. Dynamic methods based on an ordering (nonpacked)                    1. Hilbert nonpacked            2. Morton nonpacked                        III. Static methods based on an ordering                    1. Packed            2. Hilbert packed            3. Morton packed            4. VAM split R-tree            5. Top-down-greedy split (TGS) R-treeMethods I and II are useful for insertion, while method III is typically used for "bulk" creation, that is, creation of indices on a given set of objects.

Within-distance query pruning in an R-tree index


An improved method for detecting hybridized biomolecules is provided which comprises the steps of, providing a plurality of probe biomolecules on a solid support surface; pre-treating the plurality of probe biomolecules with an effective amount of a pre-treatment solution to produce a signal having an increased intensity of at least two (2) times, as compared to an identical detection method that does not include the pre-treating step; applying a buffer solution to the probe biomolecules; hybridizing the probe biomolecules with a plurality of target biomolecules to form a hybridized complex; and, developing and detecting the signal intensity. The developing step of the method may further include the steps of, treating the hybridized complex with a conjugating solution, and treating the conjugated, hybridized complex with a detection reagent.

The present invention is directed to an improved method for detecting hybridized biomolecules, such as deoxyribonucleic acid (DNA), in solid phase hybridization. The improved method results in increased hybridization signal intensities in the analysis of biomolecules.
In the analysis of biomolecules using a solid phase, a plurality of probe biomolecules may be attached to a solid polymeric matrix or substrate in a pre-determined format referred to as an array. During hybridization, the probe biomolecules are subjected to treatment with complementary target biomolecules to form hybrid duplexes or complexes. Areas of the array where duplexes or complexes form are then detected by known detection techniques.
Known hybridization techniques used in solid-phase hybridization include the Southern blotting technique, also known as the forward-blot technique, and the reverse Southern blotting technique. The Southern blotting technique allows for the mapping of a position of a DNA sequence relative to restriction enzyme sites. In the Southern blotting technique, target biomolecules are initially attached to a solid support substrate, and then the target biomolecules are treated with probe biomolecules and undergo hybridization with the probe biomolecules.
In the reverse Southern blotting technique, pre-synthesized probe biomolecules are initially attached to a solid support substrate, and then the probe biomolecules are treated with target biomolecules and undergo hybridization with the target biomolecules. The reverse Southern blotting technique does not limit the number of target biomolecules that may be used and allows for a high throughput, that is, a large volume of data may be collected in a short period of time.
Under ideal conditions, immobilized probe biomolecules should be easily accessible for hybridization with target molecules. However, under less than ideal conditions, hybridization between the probe biomolecules and the target biomolecules is often inhibited or prevented because the probe biomolecules in the array are not available for interaction with the target biomolecules. This unavailability can occur when the probe biomolecules which are initially attached to the solid support surface form duplexes or complexes with themselves or self-hybridize upon themselves, by folding back on themselves to form hairpin loop secondary structures. Such secondary structures are referred to as intra-strand interactions. The unavailability of the probe biomolecules for hybridization with the target biomolecules can also occur when the probe biomolecules hybridize with adjacent probe biomolecules on the array surface to form secondary structure attachments referred to as inter-strand interactions. The presence of intra-strand and inter-strand secondary structures on the probe biomolecules retards the process of hybridization with target biomolecules.
A known method of enhancing hybridization of complementary polynucleotides in a buffered aqueous medium under hybridization conditions is disclosed in U.S. Pat. No. 5,512,436 to Stone. Such method is concerned with increasing the rate of hybridization and includes the use of a blocking agent.
There is a need for an improved method in solid phase array analysis for detection of biomolecules that results in an increased occurrence of hybridization between the probe biomolecules and the target biomolecules, that minimizes the formation of inter-strand and intra-strand interactions on the probe biomolecules, and that results in an increased hybridization signal intensity.

Hybridization detection by pretreating bound single-stranded probes