A measuring cable travel sensor comprises a measuring cable, and a cable drum for winding on and off the measuring cable. A spiral spring is arranged non-rotatably with the cable drum coaxially therewith, on the rotary trunnion of a rotary angle sensor for sensing rotation of the cable drum. The cable drum and the spiral spring are disposed in a housing which forms at least one mechanical internal space for same. The housing has at least two flat outside surfaces which are a right angle to each other. The housing parts are in the form of plastic injection moldings, and the sensor can be assembled very easily and quickly. The external configuration of the housing makes it possible to afford very many different possible ways of fixing it in position relative to the surrounding structure. The sensor is assembled by a method affording simplicity and speed.

The invention relates to measuring cable travel sensors, and in particular, to cable travel sensors which operate on the basis of a measuring cable principle.
Measuring cable travel sensors comprise a precisely defined and positioned cable drum on to which a measuring cable is wound, generally only in a single layer, and fixed at one end.
The other free end of the measuring cable is secured to the article of which the variation in the position is to be precisely measured.
When the article moves in relative terms away from the cable drum of the measuring cable travel sensor, the angular movements of the measuring cable drum are converted into a precise travel length by means of a rotary angle sensor which is non-rotatably coupled to the measuring cable drum. A rotary torsion spring, which is operatively connected generally in coaxial relationship to the measuring cable drum, ensures that the measuring cable is wound on to the measuring cable drum when the article to be measured moves towards the cable drum.
Measuring cable travel sensors of this kind are used in various technical assemblies, for example, for determining the position of an elevator cabin in an elevator shaft for continuously monitoring the angular position of ailerons or control elevators and vertical rudders in aircraft or the like.
In order to achieve the desired level of measurement accuracy for such measuring cable travel sensors, it is necessary on one hand, to ensure absolute angular truth as between the measuring cable drum and the rotary angle sensor. This requires, inter alia, free unimpeded rotary movement of the measuring cable drum, under all operating conditions, as any impediment to the cable drum would grossly falsify the measurement result. In particular, rubbing of the cable drum against the housing, for example, as a consequence of a mechanical loading, thermal distortion of parts of the housing and so forth, must be avoided.
For this reason the housings of the measuring cable travel sensors have hitherto generally been composed of metal parts. Production using injection molding procedures with plastic material or light metal or alloy has hitherto scarcely been wide-spread by reason of the generally unsatisfactory degree of accuracy and the complicated co-operation of the individual components.
On the other hand the extent of use of measuring cable travel sensors of that kind can be increased in proportion to reduced manufacturing cost thereof and the enhanced universality of the design configuration for example of the means for securing the sensor with respect to a surrounding structure.
An object of the present invention is to provide a measuring cable travel sensor which is inexpensive to produce and which nonetheless functions precisely and which in particular permits a wide variety of possible ways of fixing same with respect to its surroundings.
A further object of the present invention is to provide a method of assembling such a sensor, which permits fast and thus inexpensive assembly of the sensor, thereby to reduce the manufacturing costs of a sensor of that kind in regard to their aspect which depends heavily on the amount of time involved in assembly of the sensor.
These objects are attained by the invention as set forth herein.
Advantageous features and configurations are further set forth in the appendant claims.
As will be apparent from the description hereinafter of a preferred embodiment of the invention the fact that the housing which encloses the mechanical internal space or cavity and which therefore accommodates the cable drum and the flat spiral spring has at least two and preferably four flat outside surfaces which are at a right angle to each other and on each side has one or preferably two mutually parallel outwardly open grooves which are each at the same spacing from the contact edges of the outside surfaces means that the housing and therewith the travel sensor can be fixed in the most widely varying orientations by means of the same clamping claws or brackets to a component of the surroundings, that is with the cable exit of the travel sensor parallel or perpendicular to the component supporting the travel sensor.
If the end faces of the housing also extend at a right angle to the outside surfaces bearing the grooves and screw means which are present in the corners of the housing which is not only rectangular but preferably square as viewed in the longitudinal direction terminate openly visibly in those end faces, then by arranging the nuts on the corresponding screws in corresponding hexagonal recesses in the end faces, it is possible to use nuts into which the corresponding screws which hold the housing together only partially penetrate from the one end, so that other screws are used from the other side, for fixing with respect to the surrounding structure. If then fixing with respect to the surrounding structure is implemented by means of a mounting angle member which, by virtue of arcuate or mutually parallel diagonal slots, permits variability in its angular positioning either with respect to the surrounding component or with respect to the sensor, the most widely varying mounting options can be implemented in a simple fashion.
The internal structure of the travel sensor is also so selected that on the one hand assembly is very simple and quick, while on the other hand production is possible using plastic injection molding, that is to say with the dimensional deviations which necessarily occur in that situation, both in manufacture and also in operational fitment of the sensor.
In that sense the housing which encloses the mechanical internal space for containing the flat spiral spring and the cable drum and which is in the form of a cuboidal portion with a smaller cuboidal portion fitted thereon, more specifically the cable fitment portion through which the cable extends outwardly from the housing in which the cable drum is rotatably disposed, does not as was hitherto conventionally the case comprise two housing portions in the form of half-shell portions, the plane of contact of which extends through the cable fitment portion.
Instead, the housing comprises one mounting plate which accommodates the flat shaped spring and which therefore involves a smaller extent in the longitudinal direction of the travel sensor, that is to say the axial direction of the rotary trunnion or journal of the rotary angle sensor, as already known hitherto, is a cup-shaped mounting plate which however is kept as small as possible in respect of its depth in the longitudinal direction so that this mounting plate, in regard to the cable fitment portion, just also involves a side wall of the latter, while the whole of the remainder of the cable fitment portion is a component part of the other mounting plate which is therefore of a substantially greater longitudinal extent.
Because of its greater axial extent in the longitudinal direction, that other mounting plate is precisely not cup-shaped, that is to say with a closed bottom, but is of such a configuration as to be open at both axial sides or ends. The outwardly directed end face is closed by a separate component which is connected non-rotatably to the rotary angle sensor. As the rotary angle sensor can also be a potentiometer, or pot, that separate component which carries the rotary angle sensor can also be referred to as the pot mounting plate member. This involves advantages in regard to manufacturing procedures, in terms of production tolerances, and also facilitates zero position adjustment of the rotary angle sensor.
In this connection, the screw means, disposed in the four corners of the two mounting plates, can be used in different ways relative to each other, by virtue of the selected radial spacing of the through openings provided for that purpose in the corners of the housing, with respect to the pot mounting plate member.
When using screws without an additional washer, the screw heads no longer project into the region of the pot mounting plate member and they serve exclusively for fixing the two mounting plates relative to each other. This is effected with two screw means which are disposed in diagonally mutually opposite relationship. The other two screw means, which are also disposed in diagonally mutually opposite relationship, are tightened with the interposition of a support washer which is of larger diameter, whereby the pot mounting plate member and therewith also the rotational position of the rotary angle sensor non-rotatably connected thereto is fixed in the desired angular position with respect to the mounting plate.
The pot mounting plate member itself is fixed on the rotary journal or trunnion of the rotary angle sensor not by means of a nut which bears against the end thereof and which acts by force-locking engagement, but rather a positively locking connection is afforded between that nut and the mounting plate by a suitable hexagonal recess in the face of the pot mounting plate member.
In the direction of the free end of the rotary trunnion or journal, the pot mounting plate member is followed by the cable drum which is screwed on the rotary trunnion or journal by means of radially acting clamping screws. In the present case, two clamping screws may be used, which include an angle of 120xc2x0 between them, whereby play-free clamping of the cable drum on the rotary trunnion or journal is possible.
At its free end the rotary trunnion or journal is cut thereinto in the longitudinal direction by a slot to such an extent that the slot can serve directly for inserting and thus positively lockingly fixing the core or center of the flat spiral spring without requiring further aids such as a transverse rivet or the like.
The two parts are brought together after the flat spiral spring is fitted into the spring chamber provided for same in the pot-shaped mounting plate. In this operation, a bar or plate portion at the outer free end of the flat spiral spring is also pushed in the longitudinal direction over a pin or projection which is integrally provided for that purpose on the mounting plate, being therefore injection molded therewith. In this case the flat spiral spring is prefabricated in such a way that, after that fitting operation, the core or center portion of the flat spiral spring is not applied radially outwardly in the spring chamber but remains centrally within the spring, without any fixing.
In this way it is possible, after insertion of the spring, to press into the spring chamber at its end a sliding plate which also comprises plastic material, engaging into a special recess, and fix it in force-locking relationship therein. The force-locking engagement is achieved by an injection-molded burr or ridge which projects deliberately along the periphery of that round sliding plate, by virtue of the plane of contact of the mold halves for that sliding plate being disposed in the central radial plane of the sliding plate. The burr, which is very narrow in the longitudinal direction of the sliding plate, is deformed in the operation of pressing it into a corresponding recess in the mounting plate, to such an extent as to afford secure force-locking fixing in that mounting plate until the two preassembled mounting plates are screwed to each other.
In this respect it is necessary for the one mounting plate unit which includes the rotary trunnion or journal of the rotary angle sensor to be fitted with its projecting slotted free end through the central opening in the sliding plate of the other mounting plate, and there, without being able to see that location, for the slot of the rotary trunnion or journal to be latched into the core or center portion of the rotary spring. This purpose requires good radial pre-adjustment which is initially implemented by virtue of the dimensioning of the central opening in the sliding plate which is only immaterially larger than the diameter of the rotary trunnion or journal. When the components are further fitted together, a flange which projects concentrically in the axial direction on the one mounting plate, more specifically the cable drum mounting plate which is open at both ends, is involved as an additional radial fixing means, insofar as that flange engages into a corresponding recess in the other mounting plate. This radial guidance effect then also makes it possible without difficulty for the two mounting plates to be firstly rotated about the longitudinal axis several times relative to each other prior to screwing of the two mounting plates relative to each other, whereby the flat spiral spring which is accommodated in the housing and which is already non-rotatably connected to the rotary trunnion or pin can be tightened in the necessary fashion.
It is only thereafter that the mounting plates are screwed relative to each other by the above-described first two screw means, followed then by zero position fixing of the rotary angle sensor by suitably turning the pot mounting plate member with respect to the rest of the housing and tightening the other two screw means.
For fixing the measuring cable at its end secured to the cable drum, the cable drum itself, near to the one side flank thereof, has a tangential slot in its winding surface in order to permit the beginning of the measuring cable to pass therethrough in a direction which is as shallowly tangential as possible, while fixing in the internal cavity of the cable drum is effected by clamping a thicker metal tube portion on to the end of the cable, which is thicker than the slot in the winding surface of the cable drum.
The material used for the housing portions is preferably POM 30 or POM G30, that is a plastic material which contains a high proportion of microscopically small glass balls which afford optimum sliding properties with respect to that plastic material relative to the metal elements involved such as the flat spiral spring, the cable drum, the rotary trunnion or journal of the rotary angle sensor and the measuring cable.
As cable drums of different sizes, in particular with respect to diameter can be fitted within one and the same housing, depending on the specific situation of use involved, the cable exit opening in the end face of the cable fitment portion must also be disposed at different locations. For this purpose, no cable exit opening is provided when producing the housing by injection molding, but rather the cable exit opening is subsequently produced at the desired location by boring.
Therefore, as the arrangement does not involve a cable fitment portion constituted by a special, harder, more wear-resistant material than the material of the housing, an acceptably low level of wear of the cable exit opening requires optimum frictional pairing with respect to the measuring cable, as an important consideration. It has been found in this respect that, with housing dimensions of about 3 cmxc3x973 cmxc3x973 cm for the main body of the housing and with the cable fitment portion projecting with respect thereto by about 1 cm and with 10 turns of the measuring cable on the measuring cable drum in mutually juxtaposed relationship in a single layer, a measuring cable of a thickness of between 0.4 and 0.6 mm is the optimum, in particular if that measuring cable comprises either a central wire or strand with between about 15 and 20 twisted strands surrounding it, or 7 strand portions which are twisted relative to each other, one thereof possibly being a central strand, wherein each of the strand portions is in turn produced from between 5 and 8 individual strands in twisted configuration.
It has also been found that the projection distance of the cable fitment portion can be optimized. More specifically, the radial spacing of the cable exit opening with respect to the winding surface of the cable drum can be optimized. In addition, the spring used is a flat shaped spring whose spring characteristic in the working range in which unwinding of the spring is possible extends in a linearly rising configuration.
In the inner end region of the spring characteristic, that is to say upon unwinding of the innermost turns of the flat shaped spring, which is not at all possible by virtue of the limited measuring cable length, in contrast an irregular and steeper configuration for the spring characteristic is acceptable.
In order to prevent unauthorized persons from opening the sensor and in order thereby to avoid possible injury due to the flat shaped spring jumping out, the assembly additionally uses vandal-proof screws, for example socket head screws, slotted screws or cross-slotted screws which cannot be opened with a normal tool because a projection sticks up in the center of the socket opening in the head of the screw, and that means that it is not possible to use a normal wrench for a socket head screw but only a special wrench with a central opening for receiving the projection. The same design configurations are also possible for dealing with cross-slotted screws and normal slotted screws.
For the same reason, the face of the sensor housing, which is remote from the rotary angle sensor, is not primarily intended for fixing the travel sensor, but generally remains free, and is therefore provided with a raised or recessed labelling, which is already formed in the injection molding operation, as a warning against unauthorized opening of the sensor, which is highly recommended for reasons relating to legal liability.
An eye at the free end of the measuring cable is injection molded on to the cable, pressed thereonto or knotted thereto, and preferably comprises high-quality steel, copper or a copper nickel compound.
In addition to the housing which encloses the mechanical internal space, it is possible to fit on to the face from which the rotary angle sensor projects a further cup-shaped housing attachment portion which encloses and protects the rotary angle sensor and in which a circuit board with an electronic evaluation system for the sensor is additionally disposed.
This housing attachment portion can again comprise the same plastic material and can also be produced by injection molding, or, if EMV-security is required, it can be produced from aluminum by extrusion or it can be produced in the form of an aluminum-coated plastic component.
Further objects, features and advantages of the invention will be apparent from the description hereinafter of a preferred embodiment of the invention.

ASM Automation Sensorik Messtechnik GmbH


A system and method for inspecting a surface of a structure for defects includes an inspection apparatus having a heating device for heating a section of the surface of the structure, an infrared camera for receiving infrared radiation from the surface in response to heating, a controller configured to generate thermographs from the received infrared radiation, and a communication device. A training system includes an expert system module configured to determine correlations between a set of thermographs generated by a thermal simulation of modeled structural elements with defects, and parameters of the modeled structural elements. A computer system communicatively coupled to the training system and the inspection apparatus, is adapted to receive thermographs received from the inspection apparatus and to detect quantitative parameters of defects in the structure using the correlations obtained from the training system.

Composite materials (hereinafter "composites") are currently used as a replacement for metallic materials in many industrial applications because of their resistance to corrosion. In the oil and gas industry for instance, composites are used in filament wound composite structures such as pipes and vessel tanks. A pipeline made from composites is shown in FIG. 14 to indicate the scale of composite structures currently used in the field. While the benefits of corrosion resistance favor their use, composites can suffer from susceptibility to other types of damage such as impact, creep and aging.
Given the susceptibilities of composites to certain types of damage, it is important to periodically inspect composites to test whether such damage has occurred or is accumulating. It is also a requirement for the inspection to be non-destructive because it is infeasible to employ invasive techniques that interrupt the continued operation of the structures in the field. Suitable non-destructive testing (NDT) techniques should be able to accurately detect typical defects in composites, be easy to apply, and permit rapid and automated inspection of large areas. It would also be advantageous for such techniques to provide in-service inspection with minimum surface preparation.
Among common NDT techniques, infrared thermography stands out as a good candidate since it provides contact-free measurement (no need for coupling media), global and focused area scans, fast acquisition, and easy operation. Limitations of the sensitivity of infrared thermography equipment have until now restricted this technique to qualitative and boundary inspections, both of which are unable to provide accurate defect size, depth data or data on the nature of any entrapped media, and are limited to detecting defects located close to the surfaces of the inspected structures.
There is therefore a need for non-destructive techniques for rapidly, reliably and cost-efficiently inspecting composite structures in an accurate quantitative manner. The present invention is addressed to this and related needs.

Method for inspecting composite structures using quantitative infra-red thermography


A bar code symbol reading system for reading bar code symbols disposed on rotating containers, such as cans and bottles, which have various capacities and arbitrary surfaces upon which the bar code symbols are printed. The system includes a laser scanning engine which produces a three-dimensional laser scanning pattern having unique geometrical characteristics over a predefined scanning region, within which each container is rotated. Owing to its unique geometry, the laser scanning pattern facilitates reading of bar code symbols printed on arbitrary container surfaces while rotated within the predefined scanning region. As a result of the present invention, a single bar code symbol reading system can be used to read bar code symbols that are printed on the arbitrary surfaces of cans and bottles.

1. Field of the Invention
The present invention relates to a machine capable of reliably collecting recyclable containers, such glass bottles, metal cans, and plastic bottles, bearing bar code symbols on arbitrary surfaces, and also to a method of collecting such diverse types of recyclable containers using a single machine.
2. Brief Description of the Prior Art
In recent times, most members of our society have become aware of the need to recycle the materials used in the manufacture of household and industrial products. Based on this general awareness, markets for recycled materials such as metal, glass, and plastic, have been created.
As part of this trend in recycling, various types of "reverse vending" machines have been developed on order to facilitate the collection of such types of recyclable materials. Presently, reverse vending machines for collecting metal cans, glass bottles, and plastic bottles for recycling have enjoyed less than great popularity among consumers. On reason for this consumer response is based on the fact that glass bottles, metal cans, and plastic bottles have had to be placed in the scanning bins (i.e., receiving slots) of different machines. In order to read the bar code symbol printed on such containers, each of these machines is equipped with a bar code symbol reader having a laser scanning pattern particularly designed to read bar code symbols on surfaces of particular geometry and at different locations along the rotatable scanning bin in which the container is rotated about its axis during laser scanning. Upon successfully reading the bar code symbol on each laser scanned container, the coin deposit paid on the container or voucher representative thereof is automatically dispensed to the consumer. Presently, a number of reverse vending machines of the type described above have been developed and sold by TOMRA, of Asker, Norway and ENVIPCO, of Fairfax, Va.
While prior art container collection machines of the type described above have been influential in advancing the trend of container recycling in our society, such machines have nevertheless suffered from a number of shortcomings and drawbacks.
In particular, due to inherent limitations of prior art laser bar code scanning equipment, such container collection machines have been designed to read bar code symbols on single types of containers, e.g., metal cans, glass bottles, plastic bottles, etc. Thus, in order to recycle containers, the consumers have had to first segregate them according to container type. Then to return a metal can for recycling, the consumer has had to insert the can into the scanning bin of a collection machine particularly designed to read bar codes located on the cylindrical surface of the can as the can and bar code are rotated about the lower region of the scanning bin. To return a glass bottle for recycling, the consumer has had to insert the glass bottle into the scanning bin of a collection machine particularly designed to read bar codes located on the conical or cylindrical surface of the bottle as the bottle and bar code symbol are rotated about another region of the scanning bin. Similarly, to return a plastic bottle (e.g., 1 or 2 liter size) for recycling, the consumer has had to insert the plastic bottle into the scanning bin of a collection machine particularly designed to rear bar codes located on the cylindrical surface of the bottle as the bottle and bar code symbol are rotated about yet another region of the scanning bin.
As a result of the above-described recycling protocol, additional time has been required to carry out recyclable container collection operations, and therefore, many consumers have been less than enthusiastic in participating in recyclable container collection efforts.
Thus, there is a great need in the art for a container collection machine which is not limited by the shortcomings and drawbacks of prior art machinery and processor.

System for reading bar code symbol on containers having arbitrary surface geometry


The present invention provides an electrical connector and an electrical connector assembly in which good and uniform electrical connection can be obtained over a broad area even in cases where there is some positional deviation between the connectors at the time of mating engagement. The electrical connector 2 has an outer housing 50, a shield member 36 which is crimped onto an outer conductor 16 of a cable 10, an inner housing 70 and a male contact 30 which is disposed inside the inner housing 70 and crimped onto a center conductor. The male contact 30 has a cylindrical contact section 82 having a plurality of arms 88, and an elastic member 90 is disposed inside the arms 88.

Electrical connector assembly 300 disclosed in Japanese Utility Model Application No. 62-28381 (shown in FIG. 6) is a conventional electrical connector in which a center conductor and an outer conductor used for ground are connected to each other. Electrical connector assembly 300 is constructed from a female connector 310, which has a cylindrical center female contact 312 and a cylindrical outer contact 314, and a male connector 350. The center pin contact 352 of the male connector 350 is engaged in the center female contact 312, and the cylindrical outer contact 354 of the male connector 350 is engaged with the inside of the outer contact 314, so that electrical connections are made therebetween.
In the connector described above, it is difficult to obtain a uniform contact pressure in cases where the center contacts 312, 352 are not properly aligned with each other in an axial direction. As a result, there is a danger that the reliability of the electrical connection will decrease. The reason for this is that although the center contact 312 is driven inward by a coil spring 316 mounted therein, engagement is made at few points, so that there is no effective compensation for misalignment.

Electrical connector having contact arms biased by an elastic member


A method of analyzing a target nucleic acid fragment is provided that is capable of being performed simply and promptly, by anyone, using a compact device without requirement of specific technique or complex operation. The method comprises timely detection of a double-stranded nucleic acid fragment formed during the polymerase extension reaction due to a specific base sequence of the target nucleic acid fragment as increase of an electrochemical response under the existence of an electrochemically active intercalator; and the kit utilizes the method.

Conventionally, in the clinical diagnosis of the infection disease due to viruses, bacteria or the like, identification of a pathogen such as viruses and bacteria has been carried out by culturing an analyte using body fluid such as blood, feces and sputum as a test sample. However, these methods have such problems that very long period of time is required to culture the analyte and culture itself dose not go smoothly in some cases of viruses or bacteria. Further, considering that a special technique is required to culture such analytes, they are not necessarily good methods to obtain a satisfactory result rapidly and simply.
A method, in which the disease agent such as a virus or bacterium is identified by an antibody-antigen reaction, has been also performed. It is a good method in view of rapidness and simplicity, since automatic analysis is possible. However, in an antibody detection method for detecting a disease agent as an antibody, there is a problem in sensitivity since sometimes lack of volume of the disease agent in a test sample results in impossibility of detecting the disease agent. Further, there is a problem that it is difficult to decide an antibody site specific to a kind of the disease agent. On the other hand, as for an antibody detection method for detecting an antibody produced in a body caused by infection of a disease agent, since some period of time is necessary from the infection with a disease agent to the production of the antibody, there is a problem that the disease agent can not be detected during the period of time.
On the contrary, a method for detecting a nucleic acid fragment having a specific base sequence in accordance with the kind of viruses or bacteria (a target nucleic acid fragment) by utilizing complementarity of the base sequence is the method that allows a direct identification of the disease agent. Therefore, it has come into wide use as a gene examination method such as a DNA probe method or a PCR (polymerase chain reaction) method. For example, the method for examining the HCV (hepatitis C virus) gene displays its greatest force in an inspection of the interferon (INF) administration or monitoring of cure in INF remedy fop hepatitis C, since the volume of HCV is directly known by the method.
It is further expected that genotype of respective disease agents such as viruses or bacteria will be elucidated, and that new curative medicines will be developed utilizing the genotype. In this case, it is very important not only to identify a disease agent but also to know genotype of the disease agent. The gene examination method is really the method that meets the request.
Furthermore, since the gene examination method can directly detect personal gene characteristics, in addition to identification of disease agent, it can be used to detect mutation of a gene that is the cause of hereditary disease or to detect a gene factor that affects aptitude of one's liability to life-style related to diseases such as cancer or diabetes. Especially, when the whole base sequences will be determined, it is expected that, as the post genome research, the relation between gene characteristics and disorder will be solved in greater detail, and that curative medicines using the gene characteristics will be developed. It is forecasted that demand for the gene examination method will continue to increase along with the progress of the post genome research.
However, since the gene examination methods preformed these days require a special technique, complex operation, special device and the like, only large scale examination centers can perform the gene examination method. In the examination of either infection disease caused by a virus, bacterium or the like or personal gene characteristics, an on the spot and quickest decision of guideline for diagnosis and remedy exerts greater effectiveness. In order to realize this situation, it is vital to provide a new gene examination method that can be operated by any operator with easiness and can give the examination result promptly.
For the purpose of improving simplicity and promptness, such gene examination methods have been developed that utilize detection of progress of a polymerase extension reaction using a target nucleic acid as a template. A method for detecting a generation process of an amplified product in real time as alteration of fluorescence strength during amplification of a specific nucleic acid region of a target nucleic acid fragment by PCR (Real Time PCR method) is a good method in terms of promptness since it does not require steps of electrophoresis of the amplified product after PCR and analysis of its result. Therefore this method is commercialized as the "TAQMAN" probe method (PE Biosystems Co.) or the Molecular Bean method (Stratagene Co.). However the methods utilize FRET (fluorescence resonance energy transfer), and have a problem that they require, on operation, a device that can measure alteration of fluorescence intensity and preparation of a specific hybridization probe in which a fluorescent dye and a quencher are combined to be labeled. Thus, they are no better than a special technique.
A method is described in "Igaku no Ayumi (Progress of Medical Science)" Vol. 173, No 12, 1995, in which alteration of fluorescence strength is detected while amplifying a specific nucleic acid region of a target nucleic acid under presence of fluorescent substance having a intercalator characteristics (IM-PCR: intercalation monitoring PCR method). This method has an advantage as the Real Time PCR method to the extent that it does not require a specific hybridization probe. However, the method also requires a device on operation that can measure the alteration of fluorescence strength. Further, the method has a problem in specificity since the fluorescent substance having intercalator characteristics connects to the all nucleic acid fragments existing in the system despite of presence or absence of PCR amplification of the specific nucleic acid region of the target nucleic acid fragment.
On the other hand, examples, in which amplification of DNA by PCR is detected as an electrochemical response by utilizing an intercalator, are disclosed in "2000 Electrochemistry Autumn Meeting, Preprint 2F17" and "2001 Electrochemistry Autumn Meeting, Preprint 1K11". These methods are good in terms of simplicity and a little space since they do not require measurement of fluorescence intensity alteration. However, there still remains a problem, on operation, in detection sensitivity and reproducibility of measurement, since the intercalator used is not a threading intercalator having redox activity and detection of DNA amplification by PCR is performed by detecting decrease of the electrochemical response. On this point, these methods are different from a method for analyzing a nucleic acid fragment according to the present invention, in which detection of a double-stranded nucleic acid fragment formed by polymerase chain reaction utilizing a target nucleic acid fragment as a template is performed by measuring increase of an electrochemical response under the presence of a threading intercalator having a redox activity.

Method and kit for analyzing target nucleic acid fragment


An electrolysis apparatus for producing ammonia, the apparatus comprising: a cathode; an anode; an electrolyte; a current source; a supply for nitrogen; and a supply for an acid, wherein the acid comprises at least one acid selected from the group consisting of: HCl, HBr, and HI.

The Haber-Bosch-Process was developed around 1910-1920 for the production of ammonia from air-nitrogen and hydrogen. Nowadays more than 130 Mt/y are produced. Hydrogen is obtained by using the energy from fossil sources. Electrochemical ways to produce hydrogen with wind or solar power could substitute fossil generated hydrogen in the Haber-Bosch process. However, the main disadvantages of the Haber-Bosch process, as part of a dynamic storage concept, arising from the high bond energy of the dinitrogen molecule are:
a. High temperatures (˜450-550° C.)
b. High pressure (˜250-350 bar)
c. Low conversion rate in a single pass (˜20%)
d. Repeated decompression, re-heating
One alternative to the Haber-Bosch process is the electrolytic production of ammonia using nitrogen and hydrogen, e.g. using gas diffusion electrodes. In such a setup nitrogen is provided at the cathode, whereas hydrogen is provided at the anode. At the cathode, nitride ions N3− are produced by the following reaction:½N2+3e−→N3−
These nitride ions then migrate to the anode, where they react with hydrogen according to the following equation:3/2H2+N3−→NH3+3e−The sum reaction is then as follows:3/2H2+½N2→NH3
Using e.g. molten salts as electrolyte at a temperature of 673 K, a Faradic efficiency η of about 72% can be reached. A main disadvantage of such a method is the double gas-diffusion electrode setup. At the anode the hydrogen may embrittle the metallic electrodes through hydride formation in the first step, which will later be split into an electron and a proton.
In the academic literature several methods were tried to implement the nitride sequence using different metals, described exemplary for Li, Mg, and Ca in Tables 1 and 2 below, and water into one single electrochemical cell as an alternative to produce ammonia.
TABLE 1Nitride sequence, step 1Nitrogen weightMetalReactioncontent in productLi6 Li + N2 → 2 Li3N40.20%Mg3 Mg + N2 → Mg3N227.74%Ca3 Ca + N2 → Ca3N218.89%
TABLE 2Nitride sequence, step 2MetalReactionReaction enthalpyLiLi3N + 3 H2O → 3 LiOH + NH3−444 kJ/molMgMg3N2 + 3 H2O → 3 MgO + 2 NH3;−708 kJ/molMg(OH)2 decomposition temperature: 350° C.)CaCa3N2 + 3 H2O → 3 CaO + 2 NH3;−840 kJ/molCa(OH)2 decomposition temperature: 550° C.)
The alkaline metals Li, Mg, Ca, as well as Sr, Ba that can be used as alternatives, can be produced by molten salt electrolysis. In the case of lithium, the electrolyte can consist of an eutectic mixture of LiCl/KCl. During electrolysis chlorine is formed on the anode, whereas lithium is formed on the cathode.
Nitride formation and migration can generally be mediated by the presence of metal ions in the electrolyte, e.g. lithium ions from LiCl. Metallic lithium, which would form on the cathode, reacts immediately with supplied nitrogen to form lithium nitride. The nitride is soluble in the electrolyte and moves to the anode. Normally—when using LiCl or similar solid electrolytes which are solid at ambient temperature and pressure, chlorine would be formed on the anode. In the case, when the anode is a hydrogen consumption electrode, the chlorine immediately reacts with hydrogen to form hydrogen chloride, which is the source of protons for the nitride ions. Eventually, ammonia is released. The reaction sequence can be summarized in the following equations.Cl−→½Cl2+e−  Anode:coupled to 3(½Cl2+½H2→HCl)Li++e−→Li  Cathode:coupled to 3Li+½N2→Li3NLi3N+3HCl→NH3+3LiCl  Summary:
Several alternative routes exist in variations of the above reaction, as described e.g. in T. Murakami et al./Electrochimica Acta 50 (2005) 5423-5426. The LiCl/KCl electrolyte and the nitride ion production are the same as in the above process. Interestingly, the protons (not hydride) are supplied by injecting water vapor. Thus, the ammonia is produced at the cathode. Oxygen and not chlorine is formed at the cathode. If the anode is made from carbon, CO2 will be formed.
In such processes, current efficiencies (Faradic efficiencies) up to 72% were observed in an academic setup. The electrolysis cell were purely experimental, thus no eye was kept on system efficiency by optimizing the electrolytic conditions. Current densities were also low around 5 mA/cm2. However, normal commercial molten salt electrolyzers operate at current densities up to 600 mA/cm2.
An alternative electrolyte used was lithium hydroxide. Temperatures above 400° C. are necessary to drive the process. However, the introduction of oxide species can destroy the electrolyte in the long term due to accumulation. Besides the molten salt electrolytes also H+-conducting membranes were used. However, significant ammonia synthesis is only observed at temperatures above 500° C.
Lithium nitride seems to be an important intermediate to reduce nitrogen and eventually form NH3 by protonation. Lithium nitride is also formed at room temperature. Tsuneto et. al., Journal of Electroanalytical Chemistry, 367 (1994) 183-188 described a low temperature, medium pressure synthesis of ammonia in a lithium-battery like environment with lithium triflate electrolyte in an ether type solvent.

Electrochemical method of ammonia generation


AV synchronous, dual chamber pacing systems are disclosed having improved sensing of ectopic ventricular depolarizations or PVCs coincidentally occurring at or shortly following delivery of an A-PACE pulse. A first ventricular sense amplifier that is blanked during and following delivery of an A-PACE pulse is coupled to active and indifferent ventricular pace/sense electrodes defining a ventricular sense vector for sensing natural ventricular depolarizations and declaring a V-EVENT. A far field PVC sense amplifier coupled to a far field PVC sense electrode pair defining a PVC sense vector detects such PVCs while the ventricular sense amplifier is blanked. A PVC declared during the ventricular blanking period by the far field PVC sense amplifier is employed to deliver a VSP pulse upon time-out of a VSP delay, if the VSP function is provided and programmed ON, and/or to halt time-out of an AV delay.

Atrial synchronized, dual chamber, pacing modes, particularly, the multi-programmable, VDD, VDDR, DDD and DDDR pacing modes, have been widely adopted in implantable dual chamber pacemakers for providing atrial and ventricular or AV synchronized pacing on demand. Such dual chamber pacing modes have also been incorporated into implantable cardioverter/defibrillators (ICDs) and into right and left heart pacing systems providing synchronized right and left heart pacing for enhancing left ventricular cardiac output as described in commonly assigned U.S. Pat. No. 5,902,324.
Such pacing systems are embodied in an implantable pulse generator (IPG) adapted to be subcutaneously implanted and at least atrial and ventricular pacing or cardioversion/defibrillation leads that are coupled to the IPG. The atrial and ventricular leads each incorporate one or more lead conductor that extends through the lead body to an exposed pace/sense electrode or cardioversion/defibrillation electrode disposed in operative relation to a heart chamber. Typically, a negative-going or cathodal voltage pacing pulse is applied through a pacing path comprising a small surface area, active pace/sense electrode (also characterized as a cathode electrode) and a relatively larger surface area, return or indifferent pace/sense electrode (also characterized as an anode electrode) to pace a heart chamber.
Such leads are typically characterized as unipolar leads if they comprise only a single active pace/sense electrode and/or a cardioversion/defibrillation electrode. In the pacing context, a unipolar lead is coupled with a unipolar IPG, wherein the electrically conductive IPG housing or "can" comprises a return or indifferent pace/sense electrode or anode electrode. Unipolar pacing and sensing takes place between the lead-borne active pace/sense electrode and the housing indifferent pace/sense electrode. A bipolar lead comprises at least two lead conductors coupled to a bipolar IPG and extending to an active pace/sense electrode, typically located at the distal end of the lead body, and an indifferent pace/sense electrode, typically located on the lead body proximal to the distal active pace/sense electrode. Bipolar pacing and sensing takes place between the lead-borne active pace/sense electrode and indifferent pace/sense electrode. In the bipolar configuration, the indifferent pace/sense electrode is usually a ring-like structure, referred to as the "ring" electrode, located proximal to the distal active pace/sense electrode, by about 0.5 cm to 2.5 cm. In this context, bipolar and unipolar sensing may also be referred to as "near-field" and "far-field" sensing, respectively. (Although "far-field" usually denotes sensing outside the chamber of interest, and the unipolar signal derived from such a unipolar pace/sense electrode pair is dominated by the near-field tip electrode signal.)
A pacing IPG capable of pacing in atrial synchronized modes typically includes atrial and ventricular sense amplifiers, atrial and ventricular pace pulse generators or "amplifiers", an operating system governing pacing and sensing functions, and components as described further herein in relation to a preferred embodiment of the invention.
In the typical dual chamber DDD pacing system, an atrial pacing (A-PACE) pulse generated by the atrial pace pulse generator is applied to the right atrial active and indifferent pace/sense electrodes to cause the right and left atria to depolarize. Similarly, a ventricular pacing (V-PACE) pulse generated by the ventricular pulse generator is applied to the right ventricular active and indifferent pace/sense electrodes to cause the right and left ventricles to depolarize. In more recently developed right and left heart pacing systems, pacing pulse generators and leads are incorporated into the pacing system to provide A-PACE and/or V-PACE pulses to the left atrium and/or ventricle.
The atrial sense amplifier is coupled to atrial active and indifferent pace/sense electrodes to detect electrical signals of the heart associated with atrial depolarizations (P-waves) and to generate an atrial sense event (A-EVENT) signal when detection criteria are met. The ventricular sense amplifier is coupled to ventricular active and indifferent pace/sense electrodes to detect electrical signals of the heart associated with ventricular depolarizations (R-waves) and to generate a ventricular sense event (V-EVENT) signal when detection criteria are met.
The pacing operating system times out various intervals from each A-EVENT, V-EVENT, A-PACE, and V-PACE to maintain synchronous depolarizations of the atria and ventricles. Such AV synchronous pacemakers that perform this function have the capability of tracking the patient's natural sinus rhythm and preserving the hemodynamic contribution of the atrial contraction over a wide range of heart rates. Maintenance of AV mechanical synchrony is of great importance as set forth in greater detail in commonly assigned U.S. Pat. No. 5,626,623.
Typically, the IPG operating system comprises a microcomputer controlled, digital controller/timer circuit that defines and times out a V-A interval (in DDD and DDDR modes) or a V-V interval (in VDD and VDDR modes) upon a V-EVENT or V-PACE pulse and times out an AV delay in response to an A-EVENT (in VDD, VDDR, DDD, DDDR modes) or in response to an A-PACE pulse (in DDD and DDDR modes) as well as a number of other intervals. An SAV delay is commenced by declaration of an A-EVENT, and a PAV delay is commenced upon delivery of the A-PACE pulse in certain DDD and DDDR pacing systems.
The A-PACE and V-PACE pulses are produced by the exponential discharge of respective atrial and ventricular output capacitors through the impedance loads in the atrial and ventricular pacing paths that each include a coupling capacitor, the active and indifferent pace/sense electrodes, and the patient's heart tissue between the pace/sense electrodes. In conventional dual chamber pacing systems, both the atrial and ventricular sense amplifiers are "blanked", i.e., uncoupled, from the respective atrial and ventricular pace/sense electrode pairs during the delivery of either of an A-PACE pulse or a V-PACE pulse and for a programmed blanking period thereafter. The gains of the atrial and ventricular sense amplifiers are normally tuned for the relatively low voltages of the heart (e.g., 0.3 mV-4.0 mV for the atrial sense amplifier and 1.0 mV-20.0 mV for the ventricular sense amplifier). The significantly greater voltages of the A-PACE and V-PACE pulses (e.g., varying between 0.5 V and 8.0 V) must be blocked from the atrial and ventricular sense amplifiers.
Moreover, a residual post-pace polarization signal (or "after-potential") remains in the pacing path due to the residual energy in the impedance load that the output capacitor is discharged into to deliver the A-PACE or V-PACE pulse. The impedance load across the output amplifier terminals comprises the impedance of the coupling capacitor, the lead conductor(s), the tissue-electrode interface impedances, and the impedance of the body tissue bulk between the active and indifferent pace/sense electrodes. The impedances of the body tissue and the lead conductor(s) may be modeled as a simple series bulk resistance, leaving the tissue-electrode interfaces and any coupling capacitors as the reactive energy absorbing/discharging elements of the total load. There are typically two tissue-electrode interfaces in a pacing path, one at the active tip electrode, and one at the indifferent ring (or IPG case or "can") electrode. The energy stored in these interfaces and any coupling capacitors dissipates after the pacing pulse through the pacing path impedance load creating the after-potential that can be sensed at each electrode and affect the ability of the sense amplifiers to sense natural or evoked cardiac events. The tip electrode is the primary after-potential storage element in comparison to the case and ring electrodes. An indifferent ring electrode typically stores more energy than does a can electrode due to differences in electrode areas.
Most current pacemaker output circuits incorporate "fast recharge" circuitry for short-circuiting the pacing path and actively dissipating or countering after-potentials during the blanking of the sense amplifier's input terminals to shorten the time that it would otherwise take to dissipate after-potentials. The primary purposes of providing a recharge operation are to ensure that the coupling capacitor(s) is recharged to an insignificant voltage level or equilibrium prior to the delivery of the next pacing pulse through it and to allow the net DC current in the pacing path to settle to zero to facilitate sensing in the same pacing path or using one of the pace/sense electrodes of that pacing path.
Thus, it is conventional to suppress or blank both of the atrial and ventricular sense amplifiers during A-PACE and V-PACE pulses for blanking periods to avoid overloading the sense amplifier. Moreover, the sense amplifiers may abruptly sense a different potential than was present at the time of initial blanking when the blanking period expires and the sense amplifier is reconnected due to the after-potentials and electrode polarization as well as the recharge function. This can produce unwanted oversensing of artifacts resulting in false declarations of A-EVENTs or V-EVENTs. Therefore, the blanking periods in pacemaker IPGs sold by the assignee of this application are nominally set at 30 ms after delivery of an A-PACE or V-PACE, but the blanking periods may be programmed as long as 45 ms in difficult sensing scenarios. There may be additional digital blanking of the sense amplifiers to avoid sensing of evoked response or other pacing artifacts, e.g., for 150 ms to 400 ms after paced events in ICDs. Such blanking periods are characterized as an atrial blanking periods (ABP) including a post atrial pace, atrial blanking period (PAABP or PAAB) and a post ventricular pace, atrial blanking period (PVABP or PVAB) or as a ventricular blanking periods (VBP) including a post atrial pace, ventricular blanking period (PAVBP or PAVB), and a post ventricular pace, ventricular blanking period (PVVBP or PVB).
In addition, a number of sense amplifier refractory periods are timed out on atrial and ventricular sense event signals and generation of A-PACE and V-PACE pulses, whereby "refractory" A-EVENT and V-EVENTs during such refractory periods are selectively ignored or employed in a variety of ways to reset or extend time periods being timed out. Atrial and ventricular refractory periods (ARP and VRP) are commenced upon an A-EVENT or V-EVENT or generation of an A-PACE or V-PACE pulse, respectively. The ARP is typically only employed by itself during atrial demand pacing in the AAI pacing mode. In dual chamber pacing modes, the ARP commenced by the A-EVENT or A-PACE pulse extends through the SAV delay or the PAV delay until a certain time following a V-EVENT terminating the SAV or PAV delay or generation of a V-PACE pulse at the expiration of the SAV or PAV delay. This post-ventricular atrial refractory period (PVARP) is commenced by a V-PACE pulse or V-EVENT based on the understanding that A-EVENTs sensed during its time-out generally reflect a retrograde conduction of the evoked or spontaneous ventricular depolarization wave and therefore are not employed to reset an escape interval and commence an SAV delay. The duration of PVARP may be fixed or vary as a function of sensed atrial rate or pacemaker defined pacing rate, with the result that in many cases relatively long PVARPs are in effect at lower rates. A total ARP (TARP) is defined as the entire duration of the ARP and the PVARP. See, for example, U.S. Pat. No. 6,311,088. Typically the ARP and VRP are set at 300 ms, and the PVARP durations are programmable in the range of 250 ms-400 ms.
The rate-adaptive VDDR, DDIR, and DDDR pacing modes function in the above-described manner but additionally provide rate modulation of a pacing escape interval between a programmable lower rate and an upper rate limit (URL) as a function of a physiologic signal or rate control parameter (RCP) related to the need for cardiac output developed by a physiologic sensor. At times when the intrinsic atrial rate is inappropriately high or low, a variety of "mode switching" schemes for effecting switching between tracking modes and non-tracking modes (and a variety of transitional modes) based on the relationship between the atrial rate and the sensor derived pacing rate have been proposed as exemplified by commonly assigned U.S. Pat. No. 5,144,949.
In order to maximize the useful life of pacing IPGs, it is desirable that the A-PACE and V-PACE pulse energies be programmed to the minimal energies required to evoke a depolarization of the atria and ventricles (i.e., to "capture" the atria and ventricles). The minimum output pulse energy which is required to capture and thus evoke a muscular depolarization within the heart is referred to as the stimulation threshold, and generally varies in accordance with the well known strength-duration curves, wherein the amplitude of a stimulation threshold current pulse and its duration are inversely proportional. One difficulty that arises from use of the blanking and refractory periods relates to the inability to use the sense amplifiers to detect the capture or loss of capture (LOC) of the atria and ventricles.
Therefore, it has been proposed to employ additional sense electrodes and sense amplifiers or differing combinations of pace/sense electrodes or cardioversion/defibrillation electrodes to sense the evoked response to a V-PACE or A-PACE as described in commonly assigned U.S. Pat. Nos. 5,331,966 and 5,683,431. A subcutaneous electrode array (SEA) formed on the surface of the IPG housing is proposed in the '966 patent for sensing the "far field" EGM at a distance from the heart along vectors selected from the electrodes of the SEA. The far field EGM is employed for a variety of reasons as set forth in the above-referenced '966 patent. The '966 patent also describes a number of other sensing schemes in the prior art for sensing the electrical activity of the heart for determining LOC or other reasons including the following.
U.S. Pat. No. 3,949,758 relates to a threshold-seeking pacemaker with automatically adjusted energy levels for pacing pulses in response to detected LOC, and describes separate sensing and pacing electrodes, which are each utilized in unipolar fashion with a third common electrode having a comparatively larger dimension, to reduce residual polarization problems.
U.S. Pat. No. 3,977,411 discloses a pacemaker having separate sensing and pacing electrodes that are each utilized in unipolar fashion. The sensing electrode comprises a ring electrode having a relatively large surface area (i.e., between 75 to 200 mm2) for improved sensing of cardiac activity (R-waves), and is spaced along the pacing lead approximately 5 to 50 mm from the distally-located tip electrode used for pacing.
U.S. Pat. No. 3,920,024 discloses a pacemaker having a threshold tracking capability that dynamically measures the stimulation threshold by monitoring the presence or absence of an evoked response (R-wave). Various electrode configurations are illustrated in FIGS. 1B and 9A-9F for purposes of sensing the evoked response, including sensing is between an intracardiac electrode and a reference electrode that is spaced some distance away from the heart or sensing between intracardiac electrodes.
U.S. Pat. No. 4,305,396 also relates to a rate-adaptive pacemaker wherein the output energy is automatically varied in response to the detection or non-detection of an evoked response (R-wave) and the detected stimulation threshold. It is stated to be preferred to use the same electrode for both pacing and sensing, such as a unipolar or bipolar system wherein there is at least one electrode located in the ventricle, but suggests that other lead designs may be utilized such that the sensing and pacing electrode are separate.
U.S. Pat. No. 4,387,717 relates to a pacemaker having a separate (i.e., non-pacing) electrode element, implanted near or in direct contact with the cardiac tissue, and positioned relative to the pacing electrodes (i.e., unipolar pacing from "tip" to "can") to provide improved P-wave and R-wave sensing with minimal interference from the pacing electrodes. The "can" functions as an indifferent electrode for sensing in combination with the separate electrode element. The separate sensing electrode is spaced from the pacing electrodes to minimize cross coupling and interference from the pacing stimulus and after-potentials. The separate sensing electrode comprises an extravascular metallic plate having a comparatively large surface area in one embodiment. In another embodiment the separate sensing electrode comprises a cylindrical metal ring mounted on the insulated pacing lead between the pacemaker and the "tip" electrode, and is described as being located along the lead to permit positioning the sensing electrode either within the heart, externally on the heart wall, or in some remote location in the vascular system away from the heart.
U.S. Pat. No. 4,585,004 relates to an implantable cardiac pacing and monitoring system, wherein the pace/sense electrodes are electrically separate from an auxiliary sense electrode system. The auxiliary sense electrode system comprises a transvenous data lead with ring electrodes for sensing located in the right ventricle (approximately 1 cm from the pacing tip electrode for R-wave sensing) and in the right atrium (approximately 13 cm from the tip electrode to be in close proximity with the S-A node), both ring electrodes being used in conjunction with the pacemaker can in unipolar sensing fashion.
U.S. Pat. No. 4,686,988 relates to a dual chamber pacemaker having atrial and ventricular endocardial leads with a separate proximal ring electrode coupled to a P-wave or R-wave sensing EGM amplifier for detecting the atrial or ventricular evoked response to atrial or ventricular stimulation pulses generated and applied to other electrodes on the endocardial lead system. The auxiliary lead system thus resembles the '004 patent.
U.S. Pat. No. 4,549,548 discloses a programmable DDD pacing system in which the selection of pace/sense electrodes is changed during each pacing cycle to optimize the choice of unipolar and bipolar atrial and ventricular operations. U.S. Pat. Nos. 4,759,366 and 4,858,610 relate to evoked response detector circuits that also employ fast recharge in at least one separate sensing electrode in either unipolar or bipolar electrode configurations in either or both the atrium and ventricle. The cardiac pacing systems function as unipolar and bipolar systems at different steps in the operating cycle. In the '610 patent, a separate electrode on the connector block of the IPG can is suggested for use as the reference electrode anode rather than the metal case itself if the case is employed as the reference electrode for the delivery of the stimulation pulse. In the '366 patent, the detected evoked response is used in an algorithm for adjusting the pacing rate.
U.S. Pat. Nos. 4,310,000, 4,729,376, and 4,674,508 also disclose the use of a separate passive sensing reference electrode mounted on the IPG connector block or otherwise insulated from the pacemaker case in order to provide a sensing reference electrode which is not part of the stimulation reference electrode and thus does not have residual after-potentials at its surface following delivery of a stimulation pulse. The aforementioned '000 patent suggests various modifications to the passive sensing reference electrode depicted in its drawings, including the incorporation of more than one passive sensing reference electrode provided on or adjacent to the IPG can, positioned as deemed necessary for best sensing, and connected to one or more sense amplifiers. No specific use of the additional passive sensing reference electrodes is suggested, although the single passive sensing reference electrode is suggested for use with a sense amplifier to detect both capture and spontaneous atrial or ventricular electrical events in a dual chamber pacing system.
Moreover, it has been proposed in the prior art to automatically select among pacing and sensing electrode pairs during the cardiac cycle or in response to a determination that lead impedance is unacceptable (which may arise from a lead fracture or electrode dislodgement or the like). See, for example, U.S. Pat. Nos. 4,958,632, 5,003,975, and 5,755,742 and the above-referenced '548 patent. According to the '548 patent, the selection of unipolar or bipolar mode of operation is based on a determination for monitoring the amplitude of sensed heartbeat signals to determine whether the sensing operation would be performed better in the unipolar or the bipolar mode. This is directed to a determination of heart performance vis-à-vis the leads involved so as to control the selection of unipolar or bipolar sensing.
Thus, considerable effort has been expended in providing systems and methods for overcoming the limitations on sensing imposed by delivery of a pacing pulse across a pair of pace/sense electrodes for a variety of purposes, including detection of LOC and determination of pacing thresholds, determination of lead impedance, and selection of the optimal pacing and sensing electrode pairs. Despite these improvements, pacing systems still employ the above-described atrial and ventricular blanking functions.
Disruption of AV electrical and mechanical synchrony frequently arises due to the spontaneous depolarization of the ventricles triggered at an ectopic site in one of the ventricles. Such a spontaneous ventricular depolarization that is not associated with a prior atrial depolarization is characterized as a premature ventricular contraction (PVC). Many of the problems resulting from the occurrence of a PVC in a patient with a dual chamber pacemaker are described more fully in U.S. Pat. Nos. 4,788,980 and 5,097,832.
PVCs that occur during the V-A interval following a prior detected R-wave or delivery of a V-PACE pulse are usually sensed as V-EVENTs that restart the V-A interval. PVCs that occur during the time-out of the AV delay and following time-out of the PAVBP are indistinguishable from sinus ventricular depolarizations that are conducted from the AV node through the Bundle of His. The resulting V-EVENT inhibits delivery of the V-PACE, and the V-A interval is commenced.
As noted above, after-potentials on the ventricular pace/sense electrodes at time-out of the PAVBP can erroneously be detected and result in declaration of a V-EVENT by the ventricular sense amplifier. The pacing system will not provide appropriate ventricular pacing to a patient's heart having AV block if electrical noise or other signals are mistakenly sensed by the ventricular sense amplifier as V-EVENTS during time-out of the AV delay. The questionable nature and consequences of mistakenly detecting V-EVENTs has led to the adoption of the practice of delivering a ventricular safety pace (VSP) pulse at a fixed time, typically 110 ms, following delivery of an A-PACE. In other words, a VSP pulse is delivered to the ventricular pace/sense electrodes if a V-EVENT is declared between the time-out of the PAVBP and a 110 ms VSP window following delivery of an A-PACE pulse. This 110 ms VSP window is often denoted the cross talk window. The 110 ms VSP window length is shorter than the normal AV conduction time in humans, so any V-EVENT declared within the VSP window is unlikely to be due to true AV conduction. The delivered VSP pulse captures the ventricles if the V-EVENT was due to cross talk, that is, sensing of the residual A-PACE energy afterpotentials. The delivered VSP pulse will not capture the ventricles if the V-EVENT reflects a PVC, because the ventricles will be refractory at that time. Thus, faced with this uncertainty, a VSP pulse is delivered at time-out of the VSP window or delay so as to ensure that the ventricles are truly contracting at a safe time after delivery of the A-PACE pulse. The VSP function is a programmable feature of prior art pacing systems that may be programmed off by the physician if desired. One form of VSP operation is set forth in U.S. Pat. No. 4,825,870, for example.
However, it frequently happens that the depolarization wavefront of a PVC reaches the pace/sense electrodes during the PAVBP, and the ventricular sense amplifier does not detect the R-wave. The after-potentials from the PVC wavefront may not be strong enough at the ventricular pace/sense electrodes to trigger a V-EVENT at time-out of the ventricular blanking period. Thus, a V-PACE pulse may be delivered at the time-out of the AV delay. The AV delay may be programmed to be long enough so that the V-PACE is delivered during the vulnerable period of the ventricles. The vulnerable period occurs during the T-wave repolarization of the ventricle (approx. 250 ms-400 ms). During the vulnerable period, there is a dispersion of refractoriness where some cardiac cells are repolarized while others are still refractory. Additional stimulation during this time has a higher likelihood of initiating a tachyarrhythmia than during periods where the cardiac cells are either completely refractory or completely repolarized.

Methods and apparatus for detecting ventricular depolarizations during atrial pacing


A liquid process assembly, the assembly including a length of pipework, and a reversible pump for selectively reciprocally moving liquid through the pipework.

Liquid process assemblies are used in a wide range of applications, for instance in continuous reactions, semi continuous reactions, and crystallisations to for instance provide a purified product. In such assemblies it can often be beneficial or required to provide turbulence in the liquid.
When cleaning such liquid process assemblies it is conventional to flush or pump a significant quantity of cleaning liquid therethrough. This therefore requires a significant quantity of cleaning liquid, and also produces a significant amount of used cleaning liquid for disposal.
According to a first aspect of the invention there is provided a liquid process assembly, the assembly including a length of pipework, and a reversible pump for selectively reciprocally moving liquid through the pipework.
The term liquid process used in the present application should be considered to include continuous reactions, semi continuous reactions, crystallisations, continuous crystallisations, and chemical continuous reactions.
The length of pipework may be a tubular device. The length of pipework may be a continuous tubular device.
The assembly may process liquid, liquid mixtures, a liquid-liquid mixture, a liquid-solids mixture, a liquid-solids-gas mixture, or a liquid-gas mixture. The assembly may process fluids. The fluid may be a liquid-solids-gas mixture, or a liquid-gas mixture.
The reversible pump may be a positive displacement replacement pump.
The reversible pump may be a fluid oscillation device. The reversible pump may be operable to oscillate fluids in the assembly.
The reversible pump may be operable to impart oscillatory motion to the assembly. The reversible pump may be operable to impart oscillatory motion to the liquid in the assembly.
The assembly may include a vessel for liquid connected to the pipework. The vessel may be located on an opposite side of the positive displacement pump to at least the majority of the pipework.
The vessel may be in the form of a feed vessel. The vessel may be in the form of a feed vessel, and more than one feed vessel may be provided.
The positive displacement pump may be a rotary pump. The positive displacement pump may be a rotary pump, and may be a lobe or gear pump.
The positive displacement pump may be controlled by a servo motor.
The positive displacement pump may have a magnetic drive located on the exterior of the pump.
The assembly may include a plurality of vessels. Each vessel may be configured to operate with a positive displacement pump. Each pump may include a controller. The controller being configured to reciprocate flow through the pump. A greater flow may be directed away from the vessels such that liquid passes through the assembly and out of the far end of the pipework. The pumps may operate at different pumping volumes. One pump may oscillate/reciprocate its flow and another pump may not oscillate/reciprocate its flow.
The frequency of reciprocal movement of the positive displacement pump may be not greater than 10 Hz, particularly 6 Hz and especially 3 Hz, but may be greater than 1 Hz.
The assembly may include a pressure absorption arrangement/accumulator. The pressure absorption arrangement/accumulator may include a closed container with gas trapped therein; may include a diaphragm; or may include a gas filled resilient member.
The positive displacement pump may include a controller. The controller may be configured such that the reciprocal movement thereof may be selectively biased to pump to a greater extent in one direction than in an opposite direction.
One or more liquid level sensors may be provided in the assembly. One or more liquid level sensors may be provided in the assembly, and the liquid level sensor or sensors may be connected to the controller such that the reciprocal movement of the positive displacement pump can be varied in response to the detected liquid levels.
The liquid level sensors may be provided on the vessel.
One or more pressure sensors may be provided in the assembly. One or more pressure sensors may be provided in the assembly, and the pressure sensor or sensors may be connected to the controller such that the reciprocal movement of the positive displacement pump can be varied in response to the detected pressure levels.
The pressure sensor or sensors may be provided on the vessel.
The assembly may be arranged such that it can be selectively pressurised. The assembly may be arranged such that it can be pressurised.
One or more level devices may be provided in the assembly. The one or more level devices may be configured to detect changes in the liquid level.
The assembly could be in the form of a chemical continuous reactor. The assembly may be in the form of a chemical continuous reactor.
The assembly could be in the form of a crystalliser. The assembly may be in the form of a crystalliser.
The vessel may include an impellor to substantially prevent crystallisation or settling out within the vessel.
The vessel may be a feed vessel. The vessel may be a feed vessel, and may include an inlet for process liquid.
An inlet may be provided downstream of the vessel. The inlet may be connected to a feed pump. The feed pump may be connected to a feed supply of material.
The vessel may include a vent. The vent may be located on an opposite side to the inlet.
An inlet may be provided upstream of the vessel. The inlet may be connected to a feed pump. The feed pump may be connected to a feed supply of material.
The pipework and vessel may be configured such that a substantially equal upper liquid level is provided in each. The pipework and accumulator vessel may be vertically configured at least generally adjacent each other. The end of the pipework may be closed. The end of the pipework may be closed, and a pressure relief valve may be provided on the end of the pipework.
The pipework may be in the form of a closed circular loop.
The pipework may include two or more circular loops. The two or more loops may be adjacent one another. The two or more circular loops being joined, such that liquid may flow therethrough.
According to a further aspect of the invention there is provided a method of carrying out a liquid process, the method including using an assembly according to any of the preceding paragraphs, and reciprocally moving the liquid in the pipework.
The reciprocal pumping of the liquid may be selectively biased to be greater in a direction away from an inlet, such that a continuous process is carried out, with additional liquid being supplied into the accumulator vessel.
The assembly may be configured such that in response to signals from the one or more liquid level sensors, the pumping is biased in either direction so as to provide a required liquid level in the assembly either side of the positive displacement pump.
The process may be carried out at an elevated pressure.
The liquid process may be a continuous reaction.
The liquid process may be a crystallisation.
Embodiments of this further aspect of the present invention may include one or more features of the first aspect of the present invention or its embodiments.
According to a still further aspect of the invention there is provided a method of cleaning a liquid process assembly according to any of the preceding paragraphs, the method comprising reciprocally moving cleaning liquid through the pipework by reciprocal pumping thereof.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
The invention further provides apparatus for cleaning a liquid process assembly, the apparatus including a positive displacement pump for selectively reciprocally moving cleaning liquid through the pipework.
The apparatus may be selectively connectable to a liquid process assembly when cleaning is required.
The apparatus may include a length of pipework selectively connectable across a part of the liquid process assembly, with the positive displacement pump part way along the length of pipework.
A reservoir may be provided part way along the length of pipework.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
According to a further aspect of the invention there is provided a fluid process assembly, the assembly including a length of pipework, and a fluid oscillation apparatus for selectively reciprocally moving liquid through the pipework.
The term fluid process used in the present application should be considered to include continuous reactions, semi continuous reactions, crystallisations, continuous crystallisations, and chemical continuous reactions.
The length of pipework may be a tubular device. The length of pipework may be a continuous tubular device.
The assembly may process liquid, liquid mixtures, a liquid-liquid mixture, a liquid-solids mixture, a liquid-solids-gas mixture, or a liquid-gas mixture.
The fluid oscillation apparatus may be a fluid oscillation generator, or device. The fluid oscillation apparatus may be operable to generate fluid oscillations in the length of pipework. The fluid oscillation apparatus may be operable to generate reciprocal movement of fluid in the length of pipework. The fluid oscillation apparatus may be a reversible pump.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
According to a further aspect of the invention there is provided a fluid oscillation assembly, the assembly including a length of pipework, and a reversible pump for selectively reciprocally moving liquid through the pipework.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
According to a further aspect of the invention there is provided a fluid assembly, the assembly including a length of pipework, and a reversible pump for selectively reciprocally moving liquid through the pipework.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
According to a further aspect of the invention there is provided an oscillation assembly, the assembly including a length of pipework, and a reversible pump for selectively reciprocally moving liquid through the pipework.
Embodiments of this further aspect of the present invention may include one or more features of the previous aspects of the present invention or their embodiments.
FIG. 1 shows a first liquid process assembly 10 usable for instance in a chemical continuous reaction. The liquid process assembly 10 may be used to carry out continuous reactions, semi continuous reactions, crystallisations, continuous crystallisations, and chemical continuous reactions.
The assembly 10 may process fluids, including liquids, liquid mixtures, a liquid-liquid mixture, a liquid-solids mixture, a liquid-solids-gas mixture, or a liquid-gas mixture.
The first assembly 10 includes a reactor vessel in the form of a length of pipework 12 (a tubular device/continuous tubular device) profiled in the form of two flattened S shapes located one above each other. A plurality of baffles 14 are shown diagrammatically in part of the pipework 12. The baffles 14 help to cause mixing and turbulence in liquid in the pipework 12. A jacket 16 is also shown around part of the pipework 12, and it is to be realised that such a jacket 16 could be provided for any part of the pipework 12, and could be provided for the whole length of the pipework 12. The jacket 16 can be used to maintain a required temperature in the pipework 12.
Immediately to the right of the jacket 16 as shown in FIG. 1 along the pipework 12, an inlet 18 is provided which leads from a feed pump 20, which pump 20 will connect to a feed supply (not shown) of material. To the right of the inlet 18 a positive displacement pump 22 is provided. A pipe 23 on the opposite side of the pump 22 connects to a vessel 24 which is partly filled with the liquid material. A pair of spaced liquid level sensors 26 are provided on the side of the vessel 24, which connect to a controller 28 for the pump 22.
At the upper end of the vessel 24 a pressure sensor 30 is provided. This can detect the pressure change as the liquid moves reciprocally, and is connected to a controller 28 that can be used to control the pump 22 dependent on the pressure measured. A level device 32 is also provided to detect the changes in the liquid level.
A back pressure relief valve 33 is provided on the opposite end of the pipework 12 to the vessel 24.
As described further below, the reversible pump (fluid oscillation device/generator) may be operable to oscillate fluids in the assembly 10. The pump 22 is in the form of a positive displacement rotary gear pump as shown in FIG. 3. The pump 22 comprises a chamber 34, which in cross section is in the form of two interconnecting circles, each locating a gear 36 with only a small space between the teeth on the gears 36 and the walls of the chamber 34. The gears 36 intermesh so that they will rotate in opposite directions. A servo motor is provided in the controller 28, which provides for quick changing between the direction of pumping, and for the pump to reach maximum pumping speed very rapidly.
An inlet 38 is provided into the chamber 34 adjacent the interconnection of the two circles in the chamber profile, with an outlet 40 from the chamber 34 of an opposite side of the chamber 34. A contactless magnetic drive, driven by the servo motor selectively rotates a one of the gears 36, which will drive the other gear 36 in an opposite direction. As the magnetic drive is contactless no seal is required between the drive and the respective gear 36, thereby preventing a leakage therebetween which would otherwise inevitably occur to at least some degree over time.
In use the pipework 12 and vessel 24 are at least partially filled with liquid pumped by the feed pump 20 through the inlet 18 once the assembly 10 is filled, the positive displacement pump 22 is operated to provide sequential forward and reverse pumping, reciprocally moving liquid into and out of the pipework 12 causing turbulence therein and an improved reaction.
The frequency of reciprocal movement of the positive displacement pump 22 may be not greater than 10 Hz, particularly 6 Hz and especially 3 Hz, but may be greater than 1 Hz. However, it should be appreciated that other suitable frequencies may be used.
The liquid level sensors 26 detect the liquid level 42 in the vessel 24, and if it is detected that this has gone above, or gone below pre-set required heights, then the bias of the sequential forward and reversing of the pump 22 can be amended to respectively pump a greater volume of liquid into or out of the vessel 24.
The reaction can be carried out on a continuous basis, with reacted liquid periodically or continuously exiting through the far end of the pipework 12. When it is required to clean the assembly 10, reaction liquid could be pumped thereoutof and a cleaning solvent or other liquid could be fed into the assembly 10 and reciprocally moved by the positive displacement pump 22 to cause cleaning. Once cleaning has been completed the used cleaning liquid can be pumped out of the assembly 10. Using the cleaning liquid with the reciprocal movement avoids using large quantities of cleaning liquid which would otherwise be the case if the cleaning liquid is simply flushed or pumped through an assembly 10.
FIG. 2 shows a further liquid process assembly 44 usable for instance for crystallisation to purify a product. The assembly 44 is similar to the assembly 10 except as will be thereinafter described. In this instance the vessel 46 is in the form of a feed vessel with an upper inlet 48 with a feed pump 50. The feed vessel 46 has a vent 52 on an opposite side to the feed inlet 48. An impellor 54 is provided in the feed vessel 46 to substantially prevent crystallisation or settling out therein.
The assembly 44 may operate in a similar manner to the first assembly 10. The positive displacement pump 22 is biased to pump material away from the feed vessel 46, with the assembly 44 being topped up or continuously fed with material through the inlet 48 to maintain the level in the feed vessel 46, as material passes out of the far end of the pipework 12.
FIG. 4 shows an alternative pump 56 which is generally similar to the gear pump/positive displacement pump 22 except that rather than gears 36 a pair of rotors 58 each with three lobes 60 thereon are provided which intermesh as shown and operate in a similar manner to the gear pump/zo positive displacement pump 22.
FIG. 5 shows a third assembly 62 with similar pipework 12 to the assembly 10. In this instance a feed inlet 63 with a feed pump 64, is provided in the pipework 12 to the left of the positive displacement pump 22.
An accumulator 66 is provided on the opposite side of the positive displacement pump 22 to the feed inlet 62, and the accumulator 66 is in the form of a closed vessel 68 with a diaphragm 70 extending thereacross. Gas 72 is provided on the opposite side of the diaphragm 70 to the pump 22.
In use as liquid is pumped into or out of the accumulator 66 this will cause the diaphragm 70 to flex in opposite directions. The gas 72 in the accumulator 66 is provided at a mean process pressure, and helps to absorb the changes in pressure caused by the changing of volume of liquid in the accumulator 66.
FIG. 6 shows a fourth assembly 74 with pipework 12 with a pair of inlet branches 76 extending thereinto. Each inlet branch 76 leads to a respective positive displacement pump 78. Provided above as shown in FIG. 6, for each of the pumps 78 there is a respective feed vessel 80, filled with liquid with a shut off valve 82 provided between the respective pump 78 and vessel 80.
Controllers 84 respective in each of the pumps 78 are arranged to reciprocate flow through the pump 78, but with a greater flow away from the vessels 80 such that liquid passes through the assembly 74 and out of the far end of the pipework 12. The pumps 78 may operate at different pumping volumes to provide a required ratio mixing of the materials in the respective feed vessels 80. In some instances only one of the pumps 78 need oscillate, whilst the other could just feed liquid into the assembly 74. Obviously if it is required to mix more than two materials a further branch with a further pump and feed vessel could be provided.
FIG. 7 shows a fifth assembly 86 which can be used for batch processing. In this instance the pipework is in the form of a closed circular loop 88, with a positive displacement pump 90 for reciprocally pumping liquid through the loop 88. The loop again has a jacket 92 and baffles 94.
An inlet pipe 96 is provided on one side of the pump 90 which connects via a valve 98 to an inlet pump 100 connected to a liquid supply. On the opposite side of the positive displacement pump 90 an outlet pipe 102 is provided leading to a valve 104 and also a back pressure relief valve 106, to permit the loop 88 to be emptied by pumping of the positive displacement pump 90 once processing of a batch has been completed. The positive displacement pump 90 can also be used to clean the loop 88 as and when required, with a cleaning liquid fed through the inlet pipe 96.
FIG. 8 shows a sixth assembly 108 usable on a semi continuous system. Here four adjacent circular loops 110 are provided each with a positive displacement pump 112. As shown a feed vessel 114 is located above the loops 110, and could be agitated, pressurised or vented. Pipework 116 extends from the feed vessel 114 to an upper part respectively of each loop 110 to provide inlets to each loop 110 through respective valves 118. Each loop 110 is connected to the adjacent loop or loops 110 via branches 120 controlled by valves 122 which permit material to pass sequentially through the different loops 110 if required.
An outlet 124 is provided at the lower end of each loop 110, with the outlets 124 provided with respective valves 126. The outlets 120 interconnect to a main outlet pipe 128 with a further valve 130, for processed material.
In use the loops 110 could all be operated simultaneously with a required residence time. Alternatively, the loops 110 can start at different times, to permit one loop 110 to be emptied and filled whilst processing in the others is continuing. A multi stage arrangement could be provided where material enters for instance the right hand loop 110 then after a first processing stage material is fed into the next loop 110, and the right hand loop 110 is then refilled. Material could proceed sequentially through all four loops 110 if required in such a multi stage process. Alternatively, material could be perhaps passed through just a selected pair of the loops 110. Additional or alternative feed vessels could also be provided and connected to each loop 110.
The invention also provides arrangements for cleaning liquid process assemblies. In FIG. 9 a simple arrangement is shown with a feed vessel 132 leading to a positive displacement pump 134 which enables liquid to be reciprocally moved through the pipework to cause cleaning without the large volume of liquids which would be required if liquid is essentially just flushed or pumped through the assembly.
In FIG. 10 an arrangement 136 is shown which could for instance be permanently located in place across a process line 138, or could be removably connectable for instance to different assemblies. The arrangement 136 here comprises a loop 140 with a reservoir 142 for cleaning liquid and a positive displacement pump 144 for reciprocally moving liquid. Cleaning liquid from the reservoir 142 could be reciprocally moved in a loop through the process line 138 when cleaning is required.
As indicated the arrangement could be selectively connected across the process line 138 with appropriate connections, or could be permanently located in place. With selective connections, the arrangement 136 could be used for cleaning a number of different process lines. In some instances it may not be required to have a reservoir contained within the loop 140.
There are thus described liquid process assemblies and methods of using them which provide for a number of advantages relative to previous arrangements. The rotary reciprocal pump provides for long term reliable and controllable reciprocal pumping in alternating directions as required. With a contactless drive as described, this removes the requirement for any mechanical seal between the drive and pump interior, thereby greatly reducing the chances of any leakage from the pump.
As indicated this arrangement readily provides for cleaning of such arrangements, but with the use of significantly reduced amounts of cleaning liquid relative to conventional arrangements.
As indicated cleaning arrangements could be provided, which could be selectively locatable in position, and for instance the same arrangement could be used to clean a number of different assemblies.
It is to be realised that a wide range of modifications may be made, and any combination of the above described features or other features can be used. The pump may take a different form, and for instance it may be possible to use a diaphragm pump. The pipework may have a different configuration. The vessels may be differently arranged and/or may include additional or different features.
Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.


A series of novel N-alkyl or oxyalkyl arylpiperidine derivatives have been prepared, including their pharmaceutically acceptable acid addition salts, wherein the N-alkyl or oxyalkyl side chain is further substituted by certain aryl or heterocyclic ring groups. These particular compounds are useful in therapy as neuroleptic agents for the control of various psychotic disorders. Typical and preferred member compounds include 4-{{4-{2-[4-(2-methoxyphenyl)-1-piperidinyl]ethyl}phenyl}}thiazole-2-amine , 4-{{4-{4-[4-(2-methoxyphenyl)-1-piperidinyl]-n-butyl}phenyl}}thiazole-2-a mine, 3-{4-[4-(2-methoxyphenyl)-1-piperidinyl]-n-butyl}-1,8,8-trimethyl-3-azabic yclo[3.2.1]octane-2,4-dione, 5-{2-[4-(2-methoxyphenyl)-1-piperidinyl]ethyl}oxindole and 3-{2-[4-(1-naphthyl)-1-piperidinyl]ethyl}-2-methyl-4H-pyrido[1,2-a]pyrimid ine-4-one, respectively. Methods for preparing all these compounds from known starting materials are provided.

In the past, various attempts have been made to obtain new and better anti-psychotic agents. These efforts have involved the synthesis and testing of various N-alkyl-N-arylpiperazine derivatives that are further substituted on the alkyl side chain by various aryl or heterocyclic ring groups. For instance, in U.S. Pat. Nos. 2,927,924 and 3,170,926, there are disclosed various N-phenylethyl-N'-arylpiperazine compounds that are reported to be useful for these purposes, while in U.S. Pat. No. 4,558,060 and in Published European Patent Application Nos. 279,598 (published on Aug. 24, 1988) and 281,309 (published on Sep. 7, 1988), there are disclosed the corresponding N-heterocyclylalkyl-N'-arylpiperazine compounds. Other efforts have involved the synthesis and testing of various arylpiperidine derivatives in this area, for example, U.S. Pat. No. 4,458,076 and Published European Patent Application No. 196,132 both teach a series of N-substituted 1,2-benzoisothiazol-3-ylpiperidine derivatives, which are also reported to be useful as anti-psychotic agents. However, none of the foregoing references teach or suggest the heretofore unavailable N-alkyl arylpiperidine derivatives or their use for anti-psychotic purposes.


An apparatus for generating a gray scale voltage in an organic light emitting display device is disclosed. In one aspect, the apparatus includes a gamma reference voltage generator, a gray scale voltage output unit and a gray scale voltage selector. The gamma reference voltage generator outputs a gamma reference voltage. The gray scale voltage output unit outputs N first gray scale voltages, based on the gamma reference voltage. The gray scale voltage selector has a lookup table in which voltage values respectively corresponding M reference gray scales are previously set, and outputs second gray scale voltages by selecting M of the N first gray scale voltages.

1. Field
The described technology generally relates to an organic light emitting diode (OLED) display.
2. Description of the Related Technology
An OLED display is a kind of flat panel display which uses an organic compound as a light emitting material. The OLED device has excellent luminance and color purity, and is thin and light. In addition, the display has low power consumption. Thus, it is expected that OLED display technology will be widely used in various types of display devices including portable display devices.
In general, OLED displays control the difference between data voltages by adjusting voltage levels of gray scale voltages so as to display an image suitable for an OLED panel having unique gamma characteristics.

Apparatus for generating gray scale voltage in organic light emitting display device


A method and apparatus for processing numerical values in a computer program. In various embodiments, the invention provides an arbitrary and expandable high-precision datatype. The datatype encapsulates large-integer data and associated operators. The large-integer data has runtime expandable precision, and the operations perform functions on large-integer data and system integer data in a manner that is functionally equivalent to corresponding language-provided integer operations. The language-provided integer operations are overloaded with the operations of the large-integer datatype, whereby a user is unburdened with special commands and syntax, and large-integer data is inter-operable with system integer data.

High-precision arithmetic is useful in computer programs that are directed to solving problems in certain disciplines. Similar classes of applications may also require arbitrary size arithmetic.
While arithmetic data sizes of 32 or 64 bits are sufficient for many applications, some highly-specialized applications may require hundreds or thousands of bits of precision. When dealing with very large numbers, relatively small—yet significant—changes will be lost with limited precision. For example, when dealing with a double precision datatype, 10^30+1 billion=10^30. In other words, 1 billion is lost in the computation. Many supercomputing application such as physics modeling and numerical methods suffer from accumulated errors due to limited-precision rounding. In another example, some supercomputing applications, such as astrophysics and encryption, deal with extremely large numbers. An "int" datatype typically offers 32 bits of size and supports values in the range of 4 billion, and the "double" datatype offers 1024 bits of size and supports values in the range of 10^400. For these applications, the range provided by "int" and "double" datatypes may be insufficient.
Special libraries have been developed to accommodate high-precision arithmetic. An example library of functions that supports arbitrary precision arithmetic is the GNU MP (GMP) library. The GMP library provides special functions that are available for use in manipulating high-precision data. To arithmetically manipulate high-precision data with the GMP library, a user must learn the names, behavior, and parameters of various specialized functions provided in the library. Thus, there is a significant learning curve that accompanies use of the GMP library. Failure to use the library correctly can lead to program failure or unexpected results.
A method and apparatus that addresses the aforementioned problems, as well as other related problems, are therefore desirable.

Arbitrary and expandable high-precision datatype and method of processing