The present invention provides a bio-augmentation composition for improving the hydrocarbon degradation efficiency of effluent treatment plant for hydrocarbon degradation in wastewater generated from hydrocarbon processing industry and a method thereof. The composition comprises a synergistic combination of selective microorganisms to develop a consortium enabling effective degradation of hydrocarbons present in wastewater and converting thereof into harmless and environment friendly substances. The invention also provides for the said microorganisms and their isolations.

Basic wastewater treatment facilities reduce organic and suspended solids to limit pollution to the environment, however often they are not up to the satisfactory level. Lack of efficient waste water treatment may cause serious environmental damages and hence it is still a major concern for various industries. Depending on the type of industry and the nature of its wastes, industries have been utilizing various methods to purify wastewater containing pollutants such as heavy metals and toxic chemicals before it can be discharged. In many parts of the world serious health problems and diseases have often been caused by discharging untreated or inadequately treated wastewater. Such discharges or water pollutants result in the spreading of disease and may cause destruction of other forms of aquatic life.
Petroleum processing industries use large quantity of water during various processing operations and produce large quantity of water contaminated with hydrocarbons, phenols, heavy metals and sulphides in varying amounts depending on the production processes. Besides that, accidental spillage of petroleum also causes contamination of water bodies. These pollutants, if left untreated can cause serious ill effects to the environment and human beings. Apart from that, if the water is to be re-used, it should be treated for removal of pollutants. The wastewater in a typical petroleum processing industry is treated in Effluent Treatment Plant (ETP) by various physico-chemical methods in which the economically recoverable products like hydrocarbons are recovered and the rest pollutants are degraded by mainly microbial action.
At present, wastewater treatment plants commonly utilize one or more processes for the treatment of wastewater. The most widely used wastewater treatment process is that of "primary treatment" which relies on plain sedimentation of settleable wastewater solids for Biochemical Oxygen Demand (BOD) and suspended solids removal. The efficiency of the primary process is in the 25-30% range. However, the results of primary treatment can be improved by the use of chemicals to enhance the settleability of wastewater solids.
In addition to the primary treatment process, there is a number of "secondary treatment" processes employed. These processes improve water quality by employing the growth of biological masses, which utilize the pollutants in the water for nutrients in their metabolic life cycles. The subsequent removal of the biological masses from the wastewater results in an effluent of an improved quality.
The "trickling filter" treatment is one secondary technique widely used in the treatment of wastewater. The filter is a packed bed of media, which provides a surface upon which a film of biological slime can grow and over which the wastewater is passed. The oxygen and organic matter in the wastewater diffuse into the film where the oxidation and synthesis of additional growth can occur. Plants using the trickling filter method can effect a carbonaceous BOD removal of 60 to 90 percent, depending mainly on the loading rate of the facility. In addition, the trickling filter process can effect an oxidation of the ammonia present in the wastewater, which is desirable.
The other and probably most widely used secondary treatment for wastewater is the "activated sludge" process. The activated sludge process can be defined as a process in which flocculated biological growths are continuously circulated and contacted with organic wastewater in the presence of oxygen. The oxygen is usually supplied by bubbling air into the sludge-liquid mixture in an aeration tank. This air can be introduced through air diffusers to develop a hydraulic motion of the contents of the aeration tank. A typical hydraulic motion involves a "spiral roll" of the contents of the aeration tank. The aeration step is usually followed by a solid-liquid separation from which a portion of the biologically active sludge is separated and recycled back to the aeration tank to provide an active source of bacterial growth to continue treatment. The activated sludge process under optimum conditions can be up to 90% effective in the removal of carbonaceous BOD. However, the "activated sludge" process is not without disadvantages as it can be readily upset by surges in the volume of wastewater and other circumstances which may prevent the attainment of the designed goals.
Microbial degradation appears to be the most environment friendly approach of oil removal as these microbes transform the pollutants to CO2 and water. Typically, the biological treatment of the wastewater is carried out in the biological treatment section by the activated sludge process. In activated sludge process wastewater containing organic matter is aerated in an aeration basin in which micro-organisms metabolize the suspended and soluble organic matter. Part of organic matter is synthesized into new cells and part is oxidized to CO2 and water to derive energy. In activated sludge systems the new cells formed in the reaction are removed from the liquid stream in the form of a flocculent sludge in settling tanks. A part of this settled biomass, described as activated sludge is returned to the aeration tank and the remaining forms waste or excess sludge. The efficiency of microbes in activated sludge process depends upon the concentration of pollutants, presence of heavy metals, availability of carbon source, temperature, pH and process conditions like mixing regime, loading rate, and the hydraulic flow rate. Gram-negative heterotrophic bacteria mainly of Pseudomonas type constitute the majority of microorganisms present in activated sludge.
The biological treatment of industrial wastewaters by activated sludge process is, however, often disrupted by shock load from organic (e.g., chlorinated organics, phenolic compounds, surfactants, and herbicides) and inorganic (e.g., heavy metals, sulfides, and ammonia) chemicals present in the wastewater stream. This disruption of biological processes results in decreased carbon removal and modification of sludge compaction properties. Little is known about the composition of mixed microbial communities in reactors when biological processes are disrupted by or recovering from. Besides that, day by day, the statutory requirement for limit of hydrocarbons in effluent discharge is being decreased by statutory bodies. For example, in India the limit has been reduced from 10 ppm to 5 ppm for oil and grease (O&G) content effective by 2009. This also calls for the invention which can be used to meet the requirement by no change in the existing ETP configuration, which is a very cost intensive affair.
Petroleum refineries produce wastewater from their various processes. This water is treated in the ETPs. Bioremediation, using activated sludge is one option for the treatment of such wastes. Biological units (trickling filter and aeration chambers) reduce the O&G content by catabolic capacities of microbes. The extent of degradation depends on presence of required catabolic gene pool as well as in their numbers. ETPs are usually unable to completely degrade the wastewater being treated in the biological unit (the aerator chambers). By providing the desired catabolic potential in adequate numbers, the overall efficiency of the treatment system can be improved by bio-augmentation and/or bio-stimulation. Bio-augmentation of activated sludge systems with specialised bacterial strains could be a powerful tool to improve several aspects in wastewater treatment processes, such as improved degradation of recalcitrant compounds.
Bioremediation strategies rely on the catabolic capacities of microbes to transform harmful pollutants into harmless compounds. Wastewater generated from the petroleum industry finds its way into soil and water bodies causing pollution problems of increasing magnitude. Despite decades of research, successful bioremediation of petroleum wastes still remains a problem. Treatment of this wastewater in ETPs is carried out by microbial biomass in the activated sludge of the ETP. The efficiency of the microbial population depends on various factors, such as the concentration of pollutants, their availability as a carbon source, temperature, pH, etc. Due to adverse stress conditions, the ETP does not run at its maximum efficiency and the treated wastewater still contains high Chemical Oxygen Demand (COD) levels. Sometimes, the required gene pool for further degradation may not be present or its titer value could be too low for sustained expression. In such cases, methods like nutrient addition (bio-stimulation) or the addition of laboratory grown bacteria that have the desired degradation capacity (bio-augmentation) could be followed. The effects of bio-stimulation on total petroleum hydrocarbons have been extensively investigated in controlled conditions and in open field experiments under optimal conditions. It is reported that nutrient supplementation may speed up the process of bioremediation, since the addition of large quantities of oil results in a high C:N ratio which is unfavorable to microbial activity. In cases where natural communities of degrading bacteria are present in low numbers or even absent, bio-augmentation, i.e., the addition of contaminant-degrading organisms can speed up the degradation process. The main advantage of bio-augmentation is the addition of a different gene pool that complements the existing one and helps in further degradation of pollutants.
Bio-augmentation, the addition of bacterial products that increases the biological activity in the system and addition of optimized nutrients could be beneficial to enhance the degradation efficiency. This helps to reduce the contaminants in faster manner. Bio-augmentation products can be either liquid or dry. Because of ease of handling, liquid products are generally preferred and can be added by a liquid metering pump drawing on a container that is replenished on a periodic basis. However, dry formulations are preferred for other applications such as waste treatment facilities. Strains used in bio-augmentation of hydrocarbons should have efficient hydrocarbon degrading ability to produce hydrocarbon solubilizing surface active agents and should have tolerance/detoxification methodology for heavy metals like vanadium, nickel and chromium etc. Since, the activated sludge operates in ambient conditions, changing seasons, particularly in tropic countries like India, where all extremes of three seasons i.e., winter, summer, rainy seasons are observed, the bio-augmentation formulation should have ability to grow and effectively remove toxicants. Bio-augmentation product should also have the ability to stabilize in aeration tank and multiply in appropriate numbers. The growth of the added microbes should also not be inhibited by already present in activated sludge and vice versa. When Gram-negative microorganisms are used for bio-augmentation, they are present as vegetative cells and as such they may be killed by chemicals, such as surfactants, heavy metals which often remain present in the wastewater. The spore forming Gram-positive bacteria are more resistant to the toxic substances.
Accordingly, there is a need to develop bio-augmentation formulations that can effectively and efficiently degrade oil and grease and which should have environment-tolerant features to work in seasonal variations. There is a further need for increasing tolerance level of the microbial consortium which can detoxify/tolerate heavy metals present in the wastewater and the process should work without any change in the existing ETP configuration.
U.S. Pat. No. 4,093,539 discloses a method for operating an activated sludge wastewater treatment plant, which utilizes rotating contactors that are partially submerged in the wastewater in the aeration tank of the activated sludge plant. The rotating contactors provide a fixed film media for the growth of biological life that is present in the recycled activated sludge in the aeration tank. The result is a more active biological coating on the fixed film media than is found on such media when used as a separate secondary treatment. In the preferred embodiment, the energy to rotate the contactors is supplied by the same compressed gas that is normally introduced below the surface of the wastewater in the aeration tank of the conventional activated sludge system
U.S. Pat. No. 5,705,072 discloses a process for bio-treatment of effluent from waste gas scrubbing systems of hydrocarbon processing facilities and for the biotreatment of sulfide and ammonia containing wastewater streams from other sources. Sulfides are minimized by bacteria cultures, particularly Thiobacillus. COD, TKN and BOD are concurrently minimized by co-cultures of the bacteria with various heterotrophs. In a version of the process, the co-cultures of the bacteria with various heterotrophs are also capable of performing nitrification, without application of nitrifiers. Acclimation of the heterotrophs to the species to be removed is accomplished by biological acclimation and enrichment reactors which reduce mycell toxicity to the heterotrophs. To control pH of the heterotrophic reaction with sulfides, magnesium oxide (MgO) and caustic are used separately or in combination. With adequate removal of the COD, TKN and BOD, nitrification and removal of ammonia can be accomplished by nitrifying bacteria cultures, particularly nitrosomonas and nitrobacters. Enrichment of the nitrosomonas and nitrobacters is accomplished by using a biological enrichment reactor. To control pH and provide a carbon source for the nitrosomonas and nitrobacters, a combination of magnesium oxide and sodium bicarbonate is utilized.
U.S. Pat. No. 6,818,211 discloses a Gram-positive microorganism, Bacillus megaterium that effectively and efficiently degrades fatty acids. A composition comprising said microorganism and a method for degrading fatty acids and grease are also disclosed. Availability of glycerol to the biodegrading microorganism was discovered to enhance biodegradation.
U.S. Pat. No. 6,251,657 discloses an apparatus and method for anaerobic biodegradation, bioremediation or bioprocessing of hydrocarbon dissolved in aqueous matrix, such as wastewater, ground water, or slurry and dissolved alkanes, aromatic hydrocarbons and/or halogenated hydrocarbons that are metabolized or co-metabolized by denitrifying bacteria.
U.S. Pat. No. 7,560,027 discloses a method and an apparatus for treating organic wastewater and sludge which remarkably reduce the generated amount of sludge at a much lower running cost, and which reduce the size and the capacity of the solubilization tank. The method and apparatus for treating the sludge employs a biological treatment system, wherein a biological treatment of wastewater is carried out, and a solid-liquid separation unit for separating a solid from a liquid in the wastewater after the biological treatment gives a treated wastewater and a sludge. The apparatus has a means for obtaining a withdrawn sludge from a part of the sludge and an alkali-treatment tank, wherein an alkali-treatment of the withdrawn sludge is carried out. The apparatus also has a biological solubilization tank which solubilizes the sludge after the alkali-treatment under an anaerobic, anoxic or microaerophilic condition, and a means for recycling the solubilized sludge to the biological treatment system.
U.S. Pat. No. 6,653,120 discloses generally biodegrading volatile organic compounds found in refinery liquid waste streams and, in particular, a process and apparatus for removing volatile organic compounds from refinery liquid waste streams. Volatile organic compound content of liquid refinery waste stream is reduced by using aqueous solutions containing microbes.
U.S. Pat. No. 7,547,394 teaches about a wastewater treatment system using aerobic granules which has a large number of sequencing batch reactor tanks with high volumetric exchange rate, a variable cycle length and constant batch volume. The batch reactors are operated for C, N removal and P is removed chemically, optionally under BioP enhanced conditions. SS are removed in a downstream separation step.
U.S. Pat. No. 7,344,643 discloses a process which utilizes an activated sludge tank, a solid-liquid separator, and a bioreactor to significantly reduce, or eliminate, waste activated sludge (WAS) within a sludge stream. A sidestream reactor is employed downstream from the bioreactor to remove soluble phosphates left in the sludge stream by the low WAS process. Within the sidestream reactor, a source of multivalent metal ions is added to a slightly alkaline sludge stream to precipitate the phosphates. The solid phosphates have a specific gravity higher than that of the organic matter in the sludge stream and may be separated from the sludge stream based upon differential settling velocity.
Burgess et al. 2000 (J E Burgess, J Quarmby and T Stephenson Vitamin addition: an option for sustainable activated sludge process effluent quality; Journal of Industrial Microbiology & Biotechnology (2000) 24, 267-274) describe the process wherein performance and metabolic rates of samples of activated sludge dosed with vitamin supplements have been compared. After initial screening, four vitamins and two metals as single supplements and in pairs were dosed continuously into the mixed liquor of an activated sludge simulation. Toxicity, oxygen demand removal, respiration rates and suspended solids were measured to monitor the effect on process efficiency. It was confirmed experimentally that an industrial wastewater stream did not contain a sufficient supply of micronutrients for efficient biological treatment. This was concluded from the observation that control sludge batches (receiving no supplements) averaged chemical oxygen demand removal efficiency of 58%. Dosing micronutrients into the mixed liquor produced removal efficiencies of up to 69%. Some of the supplements increased the respiration rate of the sludge while some decreased it, indicating a range of stimulatory and inhibitory effects. Complex interactions between micronutrients that were dosed simultaneously were evident. Several positive effects led to the conclusion that micronutrients have the potential to optimise process performance of activated sludge plants treating industrial wastewater. The addition of phosphorus/niacin and molybdenum/lactoflavin removed wastewater components that were toxic to nitrifiers as indicated through toxicity testing, thus protecting downstream nitrification/denitrification treatment processes.
Pala and Sponnza 1996 (A. I. Pala; D. T. Sponza Biological Treatment of Petrochemical Wastewaters by Pseudomonas Sp. Added Activated Sludge Culture. Environmental Technology, Volume 17, Issue 7 July 1996, pages 673-685) isolated a Pseudomonas sp. from the activated sludge of a petrochemical industry treatment plant and used as an inoculum culture for biological treatment of petrochemical wastewaters. The objective was the comparison of biological treatment efficiencies between Pseudomonas sp. added activated sludge and normal activated sludge taken from the full scale treatment plant. Experiments were carried out both in batch and continuous operations using a laboratory scale activated sludge system. Monod kinetic was used to determine kinetic coefficients from the experimental data of continuous operations. The maximum COD utilization rate constant (k), saturation constant (Ks), microbial decay rate (kd), yield coefficient (Y) and maximum specific growth rate (μmax) were determined to be 0.95 1/day, 199 mgCOD/L, 0.10 1/day, 0.30 mgMLSS/mgCOD and 0.285 1/day for normal activated sludge, respectively. These coefficients were also determined for Pseudomonas sp. added activated sludge system as 2.75 1/day, 1035 mgCOD/L, 0.08 1/day, 0.32 mgMLSS/mgCOD and 0.88 1/day, respectively. Removal efficiencies of COD, TN and phenol for lower sludge ages were found higher for the Pseudomonas sp. added activated sludge system than that of the activated sludge system. Treatment efficiencies were found to be almost the same for both systems at high sludge ages.
US Application US2008308493 discloses a system and method for treating wastewater by continuously flowing wastewater into a chemostat and continuously discharging clean water out of the chemostat. The system can include sensors and an electronic controller for online measuring ambient parameters in the chemostat and adjusting the chemostat's operating conditions accordingly.
PCT Application W02007093993 discloses to the field of hydrocarbon degradation, and more particularly, to environmentally safe bacterial compositions useful for cleaning and treating hydrocarbon-contaminated water and surfaces. The compositions have utility in degrading hydrocarbons, including petroleum, in seawater and on surfaces. The invention provides a novel bacterial isolate belonging to the Idiomarina genus (strain no. ASH1), having a 16S rRNA sequence; a novel bacterial isolate belonging to the Rhodobacteriacea genus (strain no. ASH4), having a 16S rRNA sequence; a novel bacterial isolate belonging to the Alter Omonas genus (strain no. OKI), having a 16S rRNA sequence; and a novel bacterial isolate belonging to the Alcanivorax genus (strain no ASH4), having a 16S rRNA sequence. Each of the isolates was found to be effective in degrading hydrocarbons in seawater.
PCT Application WO2004094316 relates to a petroleum-degrading bacteria using uric acid as a nitrogen source. The bacteria belong to the Alcanivorax and Acinetobacter genera.
US Application US20050106702 describes methods for the microbial degradation of petroleum pollutants including polyaromatic hydrocarbons (PAHs) using bacterial isolates from an oil refinery field.
Hedlund et al., disclose the isolation of a novel genus and species of marine bacterium that degrade polycyclic aromatic hydrocarbons, Neptunamonas naphthovorans (Appl. Environ. Microb., 65(1):251, 1999).
US Application US20040200773 relates to a highly efficient, microbial generator, bio-reactor or bio-generator that optimizes the bio-augmentation of wastewater streams, wastewater bodies, ground-waters and other aqueous discharges by generating and dispensing active, non-dormant microbes at the point or site of bio-augmentation in sufficient quantities, types, and rates that overcomes the inadequacies and cost prohibitions of prior available methods.
US Application US20060163154 discloses a method for processing environmental samples to remove or otherwise reduce the level of certain chemical species. In a preferred embodiment, the invention contemplates a process for reducing the level of inorganic and/or organic chemical species in wastewater or other aqueous or semi-aqueous environments or other waste environments. The invention further provides compositions of bacteria useful in modulating the redox potential of an environment to generate redox mediator species which facilitate the removal of particular inorganic or organic molecules from the environment samples. The redox potential is preferably modulated through microbial-mediated oxidation or reduction of metal cations under aerobic or anaerobic conditions, respectively. The invention is further directed to a computer program which facilitates the controlled modulation of the redox potential of an aqueous or semi-aqueous environment or other environments.
US Application US20080047896 describes wastewater treatment systems and methods of treating wastewater. In one exemplary method, a wastewater is split into first and second wastewater fractions. The first fraction is delivered to a membrane bioreactor, which may produce an effluent with a low pollutant concentration, and the second fraction is delivered to a biological wastewater treatment system, which may yield a higher pollution concentration yet have a shorter solids retention time. Some implementations of the invention can routinely meet or even exceed pollution discharge standards quite economically during normal operation, yet retain significant flexibility for handling seasonal or sudden variations in the flow rate of wastewater into the system. In select adaptations, waste activated sludge containing heterotrophs, autotrophs, and (optionally) polyphosphate accumulating organisms is delivered from the membrane bioreactor to the biological wastewater treatment system.
The prior art as stated above suffers from following disadvantages:                None works without change in configuration of the existing ETP configuration.        Bio-augmentation process requires strict control of pH, temperature and other parameter with costly controllers.        Requirement of specific devices for growth of microbial product or their growth and some specific reactors, bioreactors, devices etc for decontamination of wastewater.        Some products contain single microbes. Considering the complex composition of hydrocarbons, it appears impractical that a single microbe will have capability to remove all types of hydrocarbons. The consortium type approach would be desirable, which is commonly practiced in bioremediation process.        None is claimed to work effectively in extreme of three seasons i.e., winter, summer, and rainy seasons.        None of the prior disclosed inventions claims heavy metal tolerance of the microbial blend.

Bio-augmentation composition and use thereof for improving efficiency of effluent treatment in hydrocarbon processing plant


A network system for judging abnormality of a self node with high precision on the basis of information from other nodes connected to a network is provided. In each node, a frequency at which data frames to be transmitted/received among nodes cannot be received is counted every communication partner node by a reception time-out error count unit. After some node is reset and restored, a start-up signal is transmitted with an initial data frame by a start-up signal transmitting unit of the node concerned. In the other nodes receiving the start-up signal, a count result of the transmission destination node of the start-up signal by a reception time-out error count unit is returned by the monitoring result returning unit, and upon reception of the count result, the node which transmits the start-up signal makes a self-diagnosis by a self-diagnosing unit.

1. Field of the Invention
The present invention relates to a network system transmits/receives data frame among nodes connected to a network according to a predetermined protocol, and mutually diagnosing operational abnormality of nodes.
2. Description of the Related Art
High functionality, high performance, high reliability, high safety and enhancement of comfort of vehicles have recently provided the setting for increase of the mount number of electrical components of a vehicle, and the amount of information to be transmitted/received among electrical parts mounted in a vehicle has rapidly increased. Therefore, for the purpose of reducing the number of wire harnesses for transmitting information, a multiplex communication system (CAN (Controller Area Network) or the like) has been mainly adopted.
In the multiplex communication system, control ECUs as nodes for transmitting/receiving data frames are connected to a common multiplex communication line to form a network, and data communication is performed through the multiplex communication line among the nodes. In the case of a vehicle having a wide variety of control types, in order to perform data communication efficiently, nodes are classified into plural node groups which are different in attribute of communication speed to form plural networks, and the communication between different networks is performed through a data relay device.
Each ECU is normally constructed so as to be reset by a watchdog timer, and CPU monitoring based on only a watchdog timer system in which CPU is reset to avoid operational abnormality caused by runaway of CPU when CPU runs away goes mainstream. Safe performance has recently leveled up more greatly, and there is developed a control device in which the operation of CPU is monitored by mounting a large-scale integrated circuit (LSI) or the like in ECU so that CPU can be also reset when CPU fails in operation or the like.
Furthermore, in connection with the level-up of the diagnosis function, means for storing, into a backup memory or a non-volatile memory, freeze frame data for storing an operation state such as the rotational speed of an engine, a vehicle speed, etc. when a failure judgment is settled, ECU calculation status data when an ECU calculation error occurs, etc., thereby making it easily to analyze a source of subsequent failure has been recently adopted as general control.
In the case of a vehicle in which control contents are particularly complicated and the number of nodes is large, it is not easy to specify a source of failure when the vehicle breaks down or goes wrong due to deterioration of ECU or the like. Furthermore, the reset of ECU described above occurs not only due to failure of ECU itself, but also due to variation of a power supply or the like. In order to discriminate the reset caused by node abnormality such as failure or the like and the reset caused by the variation of the power supply, for example, JP-A-2002-44101 (pages 5 to 10, FIG. 1) discloses a node diagnosis method and a node diagnosis system in which a relay device as one node among plural node groups different in the communication speed attribute diagnoses failure of nodes, and it is made easy to specify abnormal node.
However, these techniques described above have a problem that the cost of ECU increases because a large-scale integrated circuit (LSI) or the like is mounted in ECU and also with respect to CPU reset based on monitoring LSI, CPU itself cannot detect abnormality.
Furthermore, according the technique described in JP-A-2002-44101, the reset frequency of abnormality-occurrence target ECU is counted and compared with those of the other nodes, and node abnormality is judged only when the count value is an excessive count value. That is, the reset frequency of the judgment target node is relatively compared with the reset frequencies of the other nodes, and it is judged whether the judgment target node is abnormal or not. Accordingly, the abnormality of the judgment target node cannot be judged with high precision. Furthermore, it cannot be recognized that reset occurs in the judgment target node itself when power supply to the judgment target node is interrupted, so that the abnormality cannot be judged with high precision.
For example, shock of a vehicle body, sudden engine stall or the like due to combustion failure of the engine under running may be caused not only by failure or deterioration of an engine constituting part such as a fuel system, an ignition system or the like, or failure or deterioration of an actuator or a sensor used to control ECU, but also by abnormality of a wire harness connected to ECU. Furthermore, these symptoms may also occur even when CPU operation of ECU fails or the power supply line is temporarily interrupted. In the instantaneous symptoms based on the temporary factor of ECU as described above, particularly the ECU reset during the idling state causes engine stall because fuel injection or ignition output is interrupted until the reset is restored. In such a case, a driver has a sense of mistrust and thus makes a claim.
Furthermore, the failure judgment is not settled in most cases because the symptoms are temporary. Therefore, it is difficult to store freeze frame data, operation status, etc. and it is not easy to specify a failure place in most cases.

Network system for diagnosing operational abnormality of nodes


A high-throughput virtual drug screening system based on molecular fingerprints and deep learning, includes a deep-learning model online-modeling subsystem and an online virtual-screening subsystem. The system combines the molecular fingerprints and a deep neural network method to construct a high-throughput virtual drug screening system. The system includes built-in structural-diversity screening libraries and realizes the online automatic construction of deep learning models and virtual screening. The system helps researchers in the drug discovery industry such as medicinal chemistry to conduct rapid screening through their desired targets to obtain potential active compounds and accelerate drug discovery.

Drug development is a costly, risky and lengthy process. Generally, developing a drug takes more than 10 years and costs billions of dollars, which are increasing year by year. In recent years, deep learning technology has made major breakthroughs in several fields such as autonomous driving, voice recognition, and image recognition. Meanwhile, deep learning technology has also made important progress in the field of biomedicine; taking advantage of deep learning in image recognition, a series of deep learning-based diagnosis applications have been developed for diseases such as skin cancer, congenital cataracts and childhood autism. The pharmaceutical industry has begun to focus on the use of deep learning technology to accelerate drug development and reduce costs. Earlier studies have shown that deep learning technology has advantages in optimizing synthetic routes, predicting pharmacological properties of drugs, predicting drug targets, and virtual screening, as compared with traditional machine learning methods (such as random forests, support vector machines, and Bayesian models).
Drug screening is a key part of drug discovery. High-throughput virtual screening can greatly reduce the screening time and cost, and is of great significance for accelerating drug development. Virtual screening methods include structure-based virtual screening methods (molecular docking) and ligand-based virtual screening (similarity, pharmacophore, three-dimensional quantitative structure-activity relationship, and machine learning). Molecular fingerprints are a method of encoding chemical structures; initially the method was mainly used for similarity search of chemical structures, but later it is found that use of molecular fingerprints has a good effect in establishing drug activity, and thus the method has been widely used in structure-activity relationship studies.

High-throughput virtual drug screening system based on molecular fingerprints and deep learning

GUANGDONG INSTITUTE OF MICROBIOLOGY (GUANGDONG DETECTION CENTER OF MICROBIOLOGY)


The present invention relates to novel antidiabetic compounds, their tautomeric forms, their derivatives, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutically acceptable compositions containing them. This invention particularly relates to novel azolidinedione derivatives of the general formula (I), and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates and pharmaceutical compositions containing them.

Insulin resistance is the diminished ability of insulin to exert its biological action across a broad range of concentrations. In insulin resistance, the body secretes abnormally high amounts of insulin to compensate for this defect; failing which, the plasma glucose concentration inevitably rises and develops into diabetes. Among the developed countries, diabetes mellitus is a common problem and is associated with a variety of abnormalities including obesity, hypertension, hyperlipidemia (J. Clin. Invest. (1985) 75:809-817; N. Engl. J. Med.; (1987) 317:350-357; J. Clin. Endocrinol. Metab., (1988) 66:580-583; J. Clin. Invest., (1975) 68:957-969) and other renal complications. (See patent application No. WO 95/21608). It is now increasingly being recognized that insulin resistance and relative hyperinsulinemia have a contributory role in obesity, hypertension, artherosclerosis and type 2 diabetes mellitus. The association of insulin resistance with obesity, hypertension and angina has been described as a syndrome having insulin resistance as the central pathogenic link-Syndrome-X. In addition, polycystic ovarian syndrome (patent application No. WO 95/07697), psoriasis (patent application No. WO 95/35108), dementia (Behavioral Brain Research (1996) 75:1-11) etc. may also have insulin resistance as a central pathogenic feature.
A number of molecular defects have been associated with insulin resistance. These include reduced expression of insulin receptors on the plasma membrane of insulin responsive cells and alterations in the signal transduction pathways that become activated after insulin binds to its receptor including glucose transport and glycogen synthesis.
Since defective insulin action is thought to be more important than failure of insulin secretion in the development of non-insulin dependent diabetes mellitus and other related complications, this raises doubts about the intrinsic suitability of antidiabetic treatment that is based entirely upon stimulation of insulin release. Recently, Takeda has developed a new class of compounds which are the derivatives of 5-(4-alkoxybenzyl)-2,4-thiazolidinediones of the formula (II) (Ref. Chem. Pharm. Bull. 1982, 30, 3580-3600). In the formula (II), V represents substituted or unsubstituted divalent aromatic group and U represents various groups which have been reported in various patent documents.
By way of examples, U may represent the following groups:
(i) a group of the formula (IIa) where R1 is hydrogen or hydrocarbon residue or heterocyclic residue which may each be substituted, R2 is hydrogen or a lower alkyl which may be substituted by hydroxy group, X is an oxygen or sulphur atom, Z is a hydroxylated methylene or a carbonyl, m is 0 or 1, n is an integer of 1-3. These compounds have been disclosed in the European Patent Application No. 0 177 353.
An example of these compounds is shown in formula (IIb)
(ii) a group of the formula (IIc) wherein R1 and R2 are the same or different and each represents hydrogen or C1-C5 alkyl, R3 represents hydrogen, acyl group, a (C1-C6) alkoxycarbonyl group or aralkyloxycarbonyl group, R4-R5 are same or different and each represent hydrogen, C1-C5 alkyl or C1-C5 alkoxy or R4, R5 together represent C1-C4 alkenedioxy group, n is 1, 2, or 3, W represents CH2, CO, CHOR6 group in which R6 group in which R6 represents any one of the items or groups defined for R3 and may be the same or different from R3. These compounds are disclosed in the European Patent Application No. 0 139 421.
An example of these compounds is shown in (IId)
iii) A group of formula (IIe) where A1 represents substituted or unsubstituted aromatic heterocyclic group, R1 represents a hydrogen atom, alkyl group, acyl group, an aralkyl group wherein the aryl moiety may be substituted or unsubstituted, or a substituted or unsubstituted aryl group, n represents an integer in the range from 2 to 6. These compounds are disclosed in European Patent No. 0 306 228.
An example of this compound is shown in formula (IIf)
iv) A group of formula (IIg) where Y represents N or CR5, R1, R2, R3, R4 and R5 represents hydrogen, halogen, alkyl and the like and R6 represents hydrogen, alkyl, aryl and the like, n represents an integer of 0 to 3. These compounds are disclosed in European Patent Application No. 0 604 983.
An example of this compound is shown in formula (IIh)
Still another class of antihyperglycemic agents are 5-substituted oxazolidine-2,4-diones and 2-substituted-1,2,4-oxadiazolidine-3,5-diones which can be represented in the formula (IIi). where V represents substituted or unsubstituted divalent aryl or hetero aryl group. W represents various groups which have been reported in various patent documents, A represents nitrogen atom or a CH group and B is an oxygen atom.
By way of examples, W may represent the following groups:
v) a group of formula (IIj), where R is (C1-C6) alkyl groups, cycloalkyl group, furyl, thienyl, substituted or unsubstituted phenyl group, X is hydrogen, methyl, methoxy, chloro or fluoro. These compounds have been disclosed in the U.S. Pat. No. 5,037,842.
An example of these compounds is shown in formula (IIk).
(vi) A group of formula (III) wherein A1 represents a substituted or unsubstituted aromatic heterocyclyl group; R1 represents a hydrogen atom, an alkyl group, an acyl group, an aralkyl group, wherein the aryl moiety may be substituted or unsubstituted or a substituted or unsubstituted aryl group, n represents an integer in the range of from 2 to 6. These compounds have been disclosed in the patent application No. WO 92/02520.
An example of these compounds is shown in formula (IIm).
(vii) A group of formulae (IIn) and (IIo), where R1 is hydrogen, (C1-C8)alkyl, (C1-C8)alkoxy, trifuoroalkoxy, halogen or trifluoromethyl group, R2is hydrogen or methyl and X is oxygen or sulfur. These compounds have been described in U.S. Pat. No. 5,480,486.
An example of these compounds is shown in formula (IIp)
Some of the above referenced hitherto known antidiabetic compounds seem to possess bone marrow depression, liver and cardiac toxicities and modest potency and consequently, their regular use for the treatment and control of diabetes is becoming limited and restricted.

Heterocyclic compounds, process for their preparation and pharmaceutical compositions containing them and their use in the treatment of diabetes and related diseases


A local area network that includes multiplexing means for establishing out-of-band channels along with corresponding Ethernet channels over shared network cabling; the out-of-band channels are configured dedicatedly for operating an IP telephony system including IP phones; a power sourcing equipment (PSE) may be further provided for remotely supplying power to the IP phones over shared network cabling; and means for access control and device location tracking may be further implemented for the IP telephony system.

Today, "Voice over Internet Protocol (VoIP)", also referred to as IP telephony, is adopted for voice communications over an Ethernet local area network (LAN). Compared to operating two separate communication networks, e.g. an Ethernet LAN for data communications and a PBX system for voice communications in an office communication environment, a converged system by applying an Ethernet LAN for both data and voice communications would be highly desirable for saving costs in deploying and operating the converged network infrastructure as well as for providing more tightly integrated data and voice applications.
Nevertheless, there are still technical and operational difficulties and limitations for such implementations because voice and data communications place very different requirements on the network performance. The Ethernet LAN implements a native "best-efforts" technology that was originally designed only for data transmission among computers. For this reason, the Ethernet networking technology in its primitive form does not provide any Qualify of Service (QoS) necessary for voice communications in terms of transmission bandwidth, packet delay, jittering, packet loss and etc. Furthermore, an Ethernet LAN inherently tends to be less reliable and secured than a traditional PBX telephone system does.
For better understanding of the background of this invention, general developments and current applications of Ethernet technology are first discussed.
Ethernet is a computer networking technology that was initially developed in 1970s as a local area networking solution for data communications among data terminal or host devices such as computers, printers, servers and etc within a local area such as an office building. Because of its simplicity and scalability, Ethernet has become the most widely adopted LAN technology and was standardized by IEEE (The Institute of Electrical and Electronics Engineers) as IEEE Standard 802.3, "Carrier sense multiple access with collision detection (CSMA/CD) access method and physical layer specifications".
According to IEEE Standard 802.3, a cable of four twisted pairs, referred to as a LAN cable hereinafter, such as Category 5 cable or the like is used to provide a full-duplex communication link between a network device such as an Ethernet switch and terminal device such as a computer. Typically, the four twisted pairs of the LAN cable are referred to as pair 1-2, pair 3-6, pair 4-5; pair 7-8. A standard 8-conductor RJ45 plug assembled with the LAN cable is usually used for connecting with a standard 8-conductor RJ45 jack. Of variants of Ethernet protocols, 10Base-T and 100Base-TX, referred to as 10/100Base-T hereinafter, refers to transmission of Ethernet data signals at 10 Mbps (bit per second) and 100 Mbps respectively by using pair 1-2 and pair 3-6 of the LAN cable while pair 4-5 and pair 7-8 of the LAN cable are left unused. 1000Base-T refers to transmission of Ethernet data signals at 1000 Mbps by using all the four pairs of the LAN cable.
An Ethernet LAN in the early days was usually found in a shared bus topology by which multiple computers were physically hooked up to a single cable segment, sending and receiving packets to each other based on the communication protocol called "Carrier Sense Multiple Access with Collision Detection (CSMA/CD)" as specified in IEEE Standard 802.3. Today, Ethernet switches are typically used for achieving much higher data throughput with improved network reliability. An Ethernet Switch is a multi-port LAN interconnection device which operates at the data link layer (layer 2) of the network hierarchy (OSI reference model). It allows simultaneous packet communications among multiple pairs or groups of computers.
For the purpose of remotely providing power to terminal devices such as IP phones, the technology of "Power over Ethernet (PoE)" has been developed that enables a unified supply of data and power through a single access point by sending power over a LAN cable. The PoE technology eliminates the need for a separate power cabling and installations of bulky AC adapters and AC outlets. As a matter of fact, such a technology has been standardized as an IEEE standard, referred to as IEEE Standard 802.3af.
According to IEEE Standard 802.3af, a Power Sourcing Equipment (PSE) operating as either a Midspan or Endpoint apparatus provides DC or low frequency inline power over two pairs of a LAN cable to a remote terminal device in one of two modes, referred to as "Alternative A" and "Alternative B". In "Alternative A", pair 1-2 and pair 3-6 of the LAN cable are used as two conducting paths for transmitting inline power as a common mode voltage. Because pair 1-2 and pair 3-6 of the LAN cable are also used for transmitting 10/100Base-T data signals in differential mode, "Alternative A" allows transmission of both power and data signal over the same two twisted pairs. Therefore, "Alternative A" is applicable to both 10/100Base-T and 1000Base-T. In "Alternative B", pair 4-5 and pair 7-8 are solely used as two conducting paths for transmitting inline power as a common mode voltage. Therefore, "Alternative B" is applicable only to 10/100Base-T. According to IEEE Standard 802.3af, a PoE enabled powered device (PD) such as an PoE enabled IP phone shall be able to support both "Alternative A" and "Alternative B". In "Alternative A", the voltage polarity of inline power received by a PD depends on the type of the LAN cable being used which is either a straight-through cable or cross-over cable.
Technically, an IP phone digitizes a channel of analog voice signal, encapsulates the digitized voice signal into a sequence of IP packets that are further carried by Ethernet packets, and the Ethernet packets are sent over an Ethernet LAN to another IP phone. For achieving satisfactory voice quality, the Ethernet LAN is required to be capable of providing adequate QoS.
Two existing Ethernet LAN techniques have been developed for providing QoS and segmenting data traffic within an Ethernet switch which can be utilized to improve the performance of IP telephony communications over an Ethernet LAN. One technique is to prioritize packets inside an Ethernet switch so that packets with higher priority are transferred or forwarded with reduced amounts of packet delay, packet jitter and packet loss. The other technique is to use virtual LAN (VLAN) technique to logically separate data traffic at the data link layer running inside an Ethernet switch so as to provide a higher level of security as well as a more manageable and better guarded bandwidth among various types of data traffic. As a matter of fact, these two techniques of packet prioritization and virtual LAN (VLAN) for switching Ethernet packets have been standardized as an IEEE standard, referred to as IEEE Standard 802.1p/Q.
Although Ethernet switches that are built with the packet prioritization and VLAN mechanism can be used to implement an Ethernet LAN for better supporting IP telephony communications, there are still several technical and operational issues that may impede the wide adoption of this technology. Some of these technical issues are described below.                1) System reliability issue. Running data and voice communications over a single Ethernet LAN is like "putting two eggs into one basket". Once the LAN crashes or becomes paralyzed by malicious attacks of denial of services (DOS), both data and voice communications are lost at the same time.        2) Security issue. Although a VLAN can separate voice traffic from other traffic in a network for implementing a more secured IP telephony system over an LAN, security is still a concern because the VLAN only logically separates voice traffic from other traffic at the data link layer and there are still chances that such a VLAN maybe compromised and voice packets maybe intercepted and eavesdropped.        3) Network upgrade issue. To upgrade an old Ethernet LAN for IP telephony communications, all the legacy Ethernet switches may have to be replaced with new Ethernet switches that are built with the packet prioritization and VLAN capabilities. Such a forklift network upgrade is not only costly but also is likely to cause disruptions to the normal operation of the network before the network becomes stabilized.        4) Network management and maintenance issue. Migrating a legacy Ethernet LAN to a new LAN for IP telephony communications also introduces extra amount of workloads and costs in setting up and managing the new network. The network setup and management become much more complicated and time consuming due to the fact that a lot more items and parameters related to the network behaviors and performances have to be configured and monitored, most of times manually by well trained and experienced IT professionals. The complexities and the need of highly trained IT personnel for setting up and managing an Ethernet LAN for IP telephony communications introduce hidden costs to the ownership of the overall network system.        5) Emergence 911 calls issue. In a traditional PBX system, a telephone is connected to a PBX port/line that is assigned with a fixed telephone number. This unique 1-to-1 mapping between a telephone number and a phone line or PBX port is used to track the physical location of the telephone. However, in an IP telephony system, the phone number of an IP phone is not associated with the port of an Ethernet LAN switch to which the IP phone is connected to. Instead the phone number is assigned based on the MAC (Media Access Control) address of the IP phone itself. MAC address is a physical address for identifying a device connected to a network. In other words, an IP phone can be connected to a different port of the LAN switch but still has the same telephone number. Such mobility nature of IP phones makes it difficult in tacking the location of the IP phone to support emergency E-911 calling in an IP telephony system.
Meanwhile, because of the benefits of the convergence of data and voice communications over an Ethernet LAN, there are demands to resolve these technical and operational limitations that may hinder the broad applications and deployments of IP telephony communications over Ethernet LANs.


Comfort noise is produced in a linear predictive speech decoder which operates discontinuously, i.e., treats data frames which alternately represent speech information and background noise. During decoding of received data frames which contain background noise-describing parameters, a first number of these data frames which have been received directly before a speech frame are excluded and replaced with one or more background noise describing frames which have been received earlier. Another number of the background noise-describing frames which have been received immediately after a sequence of speech frames are also left out during the decoding and replaced by one or more background noise-describing frames which have been received before the sequence of speech frames. This results in a minimized degradation of the background noise information and gives an optimal comfort noise on the receiver side.

In discontinuous speech coding according to the VOX-principle (VOX=Voice Operated Transmission) a unit which detects voice activity, a so-called VAD-unit (VAD=Voice Activity Detector) decides for each sound sequence received whether the received sound information represents human speech or not. The VAD-unit can have two different conditions. A first condition means that a current sound is classified as human speech and a second condition means that a certain sound is classified as non-speech.
If the VAD-unit detects that a given sound sequence represents speech then the VAD-unit generates a first condition signal and a speech coder unit is controlled to deliver a so-called speech frame which contains coded speech information. If on the other hand a given sound sequence is determined by the VAD-unit to be sound of a type which is not human speech then the VAD-unit generates a second condition signal and an SID-frame generator is controlled to deliver every N'th frame a so-called SID-frame (SID=Silence Descriptor). During the intermediate N-1 possible opportunities to send data neither the SID-frame generator nor the speech frame generator transmit any information and the transmitter is silent.
An SID-frame includes information on estimated background noise levels and estimated noise spectrums on the transmitter side.
The above method is used for example in mobile radio communication systems in order to save battery energy in the mobile terminals in order to administrate the radio bandwidth, i.e. minimize the transmission of radio energy when a given radio channel does not need to be used for the transmission of speech information. This method is, however, also applicable in other types of telecommunication systems when it is required to minimize the bandwidth used per speech connection.
It is known in the prior art in discontinuous speech coding to let a speech coder unit send an SID-frame every N'th frame when the VAD-unit detects non-speech. In known applications, such as for example in the GSM-system (GSM=Global System for Mobile Communication), approximately two SID-frames are sent per second.
The parameters included in the SID-frames: estimated background noise level and estimated noise spectrum are calculated as an average value of a current estimate and the estimates from a number of previous frames. The receiver interpolates furthermore between the received parameter values for N-1 intermediate data positions in order on the receiver side to obtain an evenly varying representation of the background noise on the transmitter side.
When the VAD-unit changes from producing the first to producing the second condition signal, i.e. from detecting speech to detecting non-speech, then normally a time interval of a given length T.sub.1, the so-called hangover, is applied in which the speech coder unit continues to deliver speech frames as if the received sound information had been human speech. If the VAD-unit after the hangover time T.sub.1 continues to register non-speech then an SID-frame is generated.
The reason for this method is amongst others that short pauses in speech inside sentences shall not be translated as non-speech, but that the speech frame generator in this situation shall continue to be activated. The application of hangover, however, does not solve the problem which noise transients with high energy contents cause. These noise transients risk namely to be interpreted by the VAD-unit as speech and if this occurs then the speech frame generator's parameter will be adapted to the spectral characteristics of the noise transients which will lead to a large degradation of the condition of the speech frame generator. A precondition for the application of hangover is therefore that the previous speech sequences should be longer than a second predetermined time T.sub.2.
When the VAD-unit changes from producing the second to producing the first condition signal, i.e. from non-speech to speech then normally no corresponding measure is taken but the speech frame generator is started immediately.
In the European patent application EP-A1-0 544 101 an example is given of how on the receiver side a background noise level can be reconstituted out of received frames which describe the background noise between transmitted speech sequences. The patent document WO-A1-95/15550 describes a method for calculating the average value of the background noise level for a number of historic frames, the current frame and up to two expected future frames out of the so-called noise-only frames. The calculated background noise level is subsequently eliminated out of the received speech signal with the purpose of forming a resulting signal of which the noise content is minimal.
When the VAD-unit changes from producing the first to producing the second condition signal, i.e. from speech to non-speech, there is a risk present that the last received SID-frame or frames parameters have been influenced by the just finished speech sequence. These parameters are namely determined as a average value of the current frame and a number of previous frames. In GSM-standard this problem is solved through a new SID-frame not being sent if the previous speech sequence was so short that the hangover had not been activated, that is to say if the speech sequence had been shorter than the time T.sub.2. Instead in this situation a copy of the SID-frame which was sent immediately before said speech sequence is transmitted. See ETSI, TCH-HS, GSM Recommendation 6.41, "Discontinuous Transmission DTX for Half Rate Speech Traffic Channels".
According to the GSM-standard, on the transmitter side the last sent SID-frame is saved when the VAD-unit changes from the second to the first condition, i.e. from non-speech to speech, in order to possibly use the SID-frame as stated above. The parameters in this SID-frame can, however, also be misleading as they can have been influenced by sound from the speech sequence which is beginning. The risk for this is especially large if the condition signal of the VAD-unit changes immediately after an SID-frame has been delivered. If the background noise level is high, then the VAD-unit probably changes the condition signal more frequently than that which is motivated by the speech information on the transmitter side, because certain speech sounds during these conditions can sometimes be misinterpreted as non-speech.

Method and arrangement for producing comfort noise in a linear predictive speech decoder


In endodontic therapy, a probe tool is disclosed which enables the removal of a broken file or instrument fragment wedged in a root canal of a tooth. A shank portion of the probe tool is made at least in part from flexible planar sheet material such as stainless spring steel. In a preferred method of use, a dental handpiece transfers oscillations or other cyclical rapid motions through the inventive probe tool to the root canal wall at the juncture with the embedded fragment. A portion of the shank end of the probe tool may be coated with abrasive material. The rapid motions or oscillations imparted to the flexible probe abrade the area where the fragment is wedged and yet minimize collateral damage to adjacent dentinal surfaces. Other types of dental handpieces can be used to transfer vibrational, reciprocating, hammering or circulatory motion to the probe tool when necessary to enhance the effectiveness of the abrading process. Another embodiment of the probe tool comprises a hook type barb to catch the loosened instrument fragment facilitating its removal from a root canal.

This invention relates to root canal therapy and in particular to the removal of a broken tool or instrument fragment lodged in the pulp chamber or root canal of a tooth.
The pulp chamber contains the pulp tissue which comprises the circulatory, connective and nerve tissue of a tooth. The pulp tissue extends from the jaw bone through one or more root canals inside each tooth to a pulp chamber. It may become necessary for a dentist or endodontic specialist to remove diseased or injured pulp tissue from root canals so that a patient can retain an original tooth in situ. Therefore a primary objective of root canal therapy is to obviate a tooth extraction procedure and its accompanying trauma to surrounding tissue and bone. As part of the therapy, the endodontic clinician removes the pulp material and shapes the root canal prior to inserting filler material in place of the original pulp.
The dental clinician must have fine dexterity and extensive training to perform a pulp extirpation successfully as root canals are very small and the canals themselves are often curved or irregularly configured. In conventional practice the clinician removes at least a portion of the crown of a tooth using a rotary bur or similar instrument to expose openings to the root canal. Small, tapered metal tools or instruments, generally referred to as files, are inserted into a root canal to remove the pulp. Files are available having different metallurgical composition and different mechanical characteristics. A manually operated file is comprised of a handle and a shank, the working end of the tool. The shank is commonly manufactured from very thin wire made from an alloy of nickel-titanium or stainless steel. The wire is helically wound and extends out from the central axis of the handle approximately 5 mm. Files are usually supplied in numbered and colored sets where the number or color on each file handle corresponds to a characteristic of a particular file. Each file in a set may differ slightly in maximum working diameter and each may serve a different specific purpose in the debriding procedure.
In practice a clinician commonly uses the fingers of one hand (usually the thumb and forefinger) to manually insert a file into the exposed opening of a root canal. The file is rotated to engage the pulp tissue while it is simultaneously being moved up and down, carrying out tissue debris and progressively enlarging and shaping the canal space. Other files are designed as reamers to enlarge a canal to a fixed diameter. A typical shank end of a file is 1 mm in diameter at the juncture with the handle and it may taper to a mere 0.2 millimeter in diameter at the tip, or distal end. Such miniscule files are quite prone to break and can become wedged or embedded in the interior dentinal wall of the canal which delays completion of normal therapy. This kind of breakage event requires additional remedial procedures and may ultimately lead to iatrogenic medical complications.
The prior art reveals a number of methods and devices available to the endodontic clinician to recover or remove a broken file. Special mechanical devices for this purpose may be manipulated directly by hand or a device may be attached to a vibratory (ultrasonic) handpiece of a kind available in most dental operatories. There are many commercial vendors and manufacturers of vibratory and ultrasonic dental handpiece devices including, as examples, Sybron Dental Specialties of Orange, Calif., Giulin Woodpecker Medical Instrument Co, Ltd of Guangxi, China, and Satelec Dental Equipment of the Acteon Group in Bordeaux, France.
U.S. Pat. No. 7,080,981 B2, issued to Terauchi in 2006, describes one such device together with accompanying implements for removing a broken instrument from a root canal. One of the Terauchi devices comprises a handle with a fork-shaped cutting end which is used to cut the internal dentin down to expose the head of the embedded broken instrument. Subsequently, after the head is exposed, a second instrument incorporating a stainless steel wire loop is used to effectively "lasso" the broken part enabling it to be withdrawn from the canal space. Other supporting instruments are also described which use tool tips designed for use with an ultrasonic handpiece to abrade or cut the area surrounding the embedded broken tip enabling the use of the wire loop device. While there may be situations in which a clinician could actually catch a broken part in this fashion, it is always desirable to limit destruction of the surrounding dentin as much as possible to better preserve the tooth. If an embedded part is actually free enough to be grabbed, a more conventional and common approach utilizes a very small forceps known as a Steiglitz forceps to grasp a broken piece without having to resort to lassoing.
A patent application publication, U.S. 2003/0157458 A1, by Buchanan describes a number of dental instrument tool tips for performing endodontic procedures. Some of the tips illustrated have abrasive coatings and others have radiused ends to minimize troughs and scratches within the root canal when the tips are used in conjunction with an ultrasonic handpiece. Buchanan discloses tool tips for ultrasonic dental handpieces which are described as less prone to damage a tooth. Inadvertent damage to tooth structures using various kinds of vibratory handpieces is a common and continuing problem in the field of endodontics. Root canals are dimensionally minute, and even well-trained and manually adept clinicians do not have perfect physical control using vibratory instruments within the canal space. As a consequence, abrupt or unintentional movements may cause unwanted removal of dentin material. When scratches and troughs or "ledges" are carved within the canal, small voids are created which are difficult to see even with the aid of dental magnifiers. Therefore it becomes difficult to fully extirpate and sanitize the canal for purposes of complete obturation. If left unfilled, these voids can become repositories for harmful bacteria. In the Buchanan invention, the tool tips are fixedly attached to the ultrasonic handpiece either by a threaded connection or by a mechanical interlock typically used to chuck a driven tool. As such, small erroneous movements by the clinician using an ultrasonic handpiece—even one equipped with Buchanan's less damaging tool shapes—may well induce unwanted material removal and damage to canal surfaces,
Another approach to endodontic treatment depicted by Laufer in U.S. Pat. Publ. 2014/0080090 employs what might be called a waterjet in miniature. Laufer shows a dental handpiece which drives a rotary device that creates a vortex-like "micro-tornado" where water mixed with an abrasive is forced through a small cannula to remove pulp and debris and diseased tissue. This device would be new to endodontic therapy and it remains to be seen whether micro-tornadic jets of water-borne slurry can be manipulated accurately enough to perform effectively in standard endodontic clinical practice. If pressures sufficient to remove calcified dentin are achievable through a micro-cannula of this nature, then the same limitations of an ultrasonic handpiece with a rigidly fixed end tool would apply to the micro-tornado device. Slight inadvertent movements by the clinician may have quite adverse consequences for a patient's tooth.
A different unconventional approach, U.S. Pat. No. 7,677,892 B2 (2010) awarded to Alexandrovskiy et al. describes how two electrodes shaped into a small cylinder can be inserted into a root canal to weld the broken piece of a file to the tip of one of the electrodes. The broken file is thereby unified with the electrode and this combination can be withdrawn from the root canal interior. While the concept of welding broken pieces together sounds plausible, in actual practice manipulating an electrode in a curved root canal so that it contacts some deeply embedded file fragment may in many instances be clinically unachievable. At the present time this technique is not commonly used in domestic endodontic practice.
A technique analogous to, and referenced by Alexandrovskiy et al. is used to dissolve a broken file tip electrochemically by the continuous application of electric current. However this electrochemical technique has a tendency to exceed physiologically acceptable temperatures within the confines of a root canal. It is also difficult for the patient in the operatory because it requires a relatively long time to work effectively and can contribute to undesirable toxic aftereffects.

Root canal probe tool and method of removing a broken instrument fragment from a root canal


An improved output voltage detection circuit for a traffic signal controller which is capable of minimizing an operational characteristic variation with respect to the operational temperature variation and enabling a compact product. The circuit includes a detection voltage dividing unit for dividing a detection input voltage having an alternating current component applied to a traffic signal system into voltages having a predetermined level, a latch unit for latching a voltage from the detection voltage dividing unit and generating a detection output voltage, a zero crossing detection signal generation unit for detecting a zero crossing timing from an alternating current voltage power and generating a zero crossing detection signal, a memory unit for storing a delay algorithm therein, and a central processing unit (CPU) for reading a delay algorithm the zero crossing detection signal from the memory unit, performing a delay programming, and applying a latch clock signal to the latch unit as much as a programmed delay constant.

1. Field of the Invention
The present invention relates to an output voltage detection circuit for a traffic signal controller, and in particular to an improved output voltage detection circuit for a traffic signal controller which is capable of reducing a characteristic variation based on an operational temperature variation, implementing a hybrid integration device, enabling a compact product, and adjusting a detection reference point by a software-based method.
2. Description of the Conventional Art
In the traffic signal controller, there is provided a function that the state of a traffic light ON/OFF signal (lamp on/off signal) is detected in real time for evaluating whether a signal control is normally performed.
The method for detecting whether a signal control is normally performed is classified into two methods. Between the methods, a method is directed to detecting whether a voltage is normally supplied to a traffic light ON/OFF cable which outputs an ON signal, and the other method is directed to detecting whether a voltage is not supplied to a traffic light ON/OFF cable which outputs an OFF signal.
Generally, since checking whether an ON state is correctly generated is important, among the above-described detection methods, the previous method is used for the group of red lights (PR: a pedestrian red light, R: a vehicle red light, Y: a vehicle yellow light). In addition, since whether an OFF state is correctly generated is important, among the above-described detection methods, the later method is used for the group of green light (PG: a pedestrian green light, G: a vehicle green light, A: a vehicle left-turn or right-turn light.
In the traffic signal controller, to detect whether a voltage is normally inputted into the traffic signal controller is important. In the normal state, a traffic signal control is continuously performed. In the abnormal state, a traffic signal control is stopped because a traffic accident may occur, and an on-and-off operation is performed.
As shown in FIG. 1, the conventional output voltage detection circuit for a traffic signal controller includes a detection voltage dividing unit 11 for dividing a detection input voltage VI having an alternating current component, which is applied to a traffic signal system, into voltages having a predetermined level, a photo-coupler 12 for receiving an output voltage from the detection voltage dividing unit 11, and a signal converter 13 for outputting a low level voltage when a voltage is periodically inputted through the photo-coupler 12 and outputting a high level voltage when a voltage is periodically not inputted.
Here, the detection voltage dividing unit 11 includes a resistor R11 which is connected in series with the input terminal, and a diode D11 and a resistor R12 which are connected in parallel with the resistor R11 and the input terminal.
The photo-coupler 12 includes a light emitting diode LED connected in parallel with the detection voltage dividing unit 11 and the resistor R12, and a photo-transistor PTR which is turned on and off in accordance with a detection of the light emitting diode LED.
In addition, the signal converter 13 includes a resistor R13 connected between a power terminal voltage VCC and a photo-transistor PTR of the photo-coupler 12, a resistor R14 and a condenser C11 connected in series between the collector of he photo-transistor PTR of the photo-coupler 12 and a ground, a diode D12 connected in parallel with the resistor R14, and an output buffer BUF11 commonly connected with the resistor R14 and the condenser C11 for outputting an output detection voltage VO.
The operation of the conventional output voltage detection circuit for a traffic signal controller will now be explained with reference to the accompanying drawings.
First, when a power is supplied to a traffic signal ON/OFF cable for turning on/off the traffic signals, the detection input voltage VI having an alternating current component which is fed-back from the traffic signal ON/OFF cable is divided into voltages having a predetermined level by the resistors R11 and R12 and the thusly divided voltages are supplied to the photo-coupler 12.
Here, when the detection input voltage VI is normally inputted, the level thereof is ranged from 120 volts to 220 volts. The light emitting diode LED and the photo-transistor PTR of the photo-coupler 12 are repeatedly turned on/off at a period corresponding to the power frequency.
Namely, when the detection input voltage VI is inputted, the photo-transistor PTR of the photo-coupler 12 is turned on, and the power terminal voltage VCC is applied to the ground terminal through the photo-transistor PTR. A waveform as shown in FIG. 2B is outputted in the interval T1 from the collector of the photo-transistor PTR. When the detection input voltage VI is not applied, since the photo-transistor PTR of the photo-coupler 12 is turned off, and the power terminal voltage VCC is charged by a time constant (T=R14.times.C11) into the condenser C11 through the resistor R14, the collector of the photo-transistor PTR outputs a high level voltage in the interval T2 as shown in FIG. 2B.
At this time, at the moment when the photo-transistor PTR is turned on, since the voltage is quickly discharged from the diode D12 and the photo-transistor PTR of the signal converter 13 to a ground, while the power is supplied to the traffic signal on/off cable, namely, while the detection input voltage VI is inputted, the output buffer BUF11 outputs a low level detection output voltage VO in the interval T1 as shown in FIG. 2.
On the contrary, when a detection input voltage VI is not inputted, a high level detection output voltage VO as shown in FIG. 2C is outputted in the interval T2.
The detection output voltage VO outputted from the output buffer BUF11 of the signal converter 13 is applied to the system controller (not shown). The system controller (not shown) judges whether a voltage input/output is normally performed with respect to the traffic signal.
Generally, the operational temperature of the traffic signal system is set at -34.degree. C..about.+74.degree. C. The voltage feeding-back system is configured such that an input voltage is not detected below AC 15 volts, and the input voltage is detected above AC 25 volts.
In addition, the traffic signal controller is configured such that 48 traffic lights are driven. Therefore, the traffic signal controller outputs 48 has an output circuit of 48 signals. Therefore, in the output voltage feeding-back circuit, the routines are performed 48 time.
However, in the conventional output voltage detection circuit for a traffic signal controller, the photo-coupler 12 is installed as an important element in the circuit. Since the turning-on current of the photo-coupler 12 is varied, the start point of the detection voltage is disadvantageously varied. In addition, it is difficult to configure the apparatus which is capable of satisfying the voltage detection characteristic within a range of the operational temperature of the apparatus.
Furthermore, since it is difficult to manufacture a hybrid IC consisting of the photo-transistor PTR and the light emitting device (LED), it is impossible to manufacture a compact product.

Output voltage detection circuit for traffic signal controller


A conveyor belt system includes a splice rod having a j-shaped hook on each end thereof and a plurality of links for receiving the splice rod therethrough. The links further include a specially modified link end for securing the rods.

One of the most commonly used types of conveyor belts for carrying diverse products along both straight and horizontally curved paths is a grid conveyor belt. Examples of conventional grid conveyor belts are the Cam-Grid® and the heavy duty Cam-Grid® conveyor belts available from Cambridge, Inc., the assignee of the present invention. A grid conveyor belt, as shown generally in U.S. Pat. No. 6,354,432, the entire contents of which are hereby incorporated by reference, includes a plurality of spaced transverse rods slidably interconnected by at least two rows of U-shaped connecting links, i.e., the tension bearing members, disposed respectively along the inner and outer edges of the rods. The terminal ends of the transverse rods are formed into enlarged heads or button heads which retain the links on the rods and welds are then provided to secure the link to the button head and to the rod, thereby preventing rotational movement of the links on the transverse rods. The connecting links are disposed in a nested relationship relative to one another with slots being provided in the links in order to slidably receive the transverse rods.
Grid conveyor belts of this type have met with overwhelming market approval because of their ability to travel in straight line conveyor paths as well as in curved conveyor paths, thus making grid conveyor belts ideal for use on spiral cage conveyors. However, when the belt is in need of repair due to breakage or maintenance, the presence of the button head ends and welded ends requires the use of special tools such as a grinder and bolt cutter and welding in order to part an endless belt or to reconnect or splice two separate ends of a belt. In addition, special threaded connector rods with end nuts have to be used to replace the rods with the button head ends when performing repair/maintenance in the field.
Flat wire conveyor belts have also been in the market for many years, as shown for example in U.S. Pat. No. 2,619,306, the contents of which are hereby incorporated by reference. Flat wire conveyor belts are generally low maintenance and when positively driven with sprockets have little to no lateral shifting. With reference to FIG. 1, there is disclosed a flat wire conveyor belt 10 comprising a plurality of pickets 12, sometimes also referred to as wickets, and interconnecting rods 14 about which the pickets hinge. The pickets of the belt define the tension bearing members and support the product to be conveyed and the rods are utilized to hold the components of belt together. This type of flat wire conveyor belts also utilize upset rod ends 16, i.e., button head shaped ends, for rod retention. The compression between the pickets keep them from moving inward of the button head ends, while the button head ends prevent the pickets from moving outwardly. Flat wire conveyor belts of this type can also be used in both straight and turn applications. A second type of flat wire conveyor belt 10′, as shown in FIG. 2, utilizes mechanically clinched rod ends 16′ for rod retention. These type of belts are used only in straight run applications.
Flat wire conveyor belts have similarly met with long term market approval. However, when the belt is in need of repair due to breakage or maintenance, the presence of the button head or clinched rod ends requires the use of special tools such as a grinder or bolt cutters and welding or special hand tools in order to part an endless belt or to reconnect or splice two separate ends of a belt. In addition, special threaded or partially clinched connector rods with end nuts have to be used to replace the rods when performing repair/maintenance in the field.
While market trends are dictating that improvements be made to reduce conveyor system down time, employers are finding that maintenance resources are decreasing in both quantity and skill base. Accordingly, there exists a need in the marketplace for a flat wire conveyor belt having a connector rod that can quickly and easily be used to splice together and repair a conveyor belt with a minimal use of tools or skill.

Quick splice conveyor belt system and method therefor


When theft protection of a computing device is initiated, credentials of the user are provided to one or more services that verify the credentials and generate a recovery key. A data value is generated based on the recovery key and an identifier of the computing device (e.g., by applying a cryptographic hash function to the recovery key and the computing device identifier), and the data value is provided to the computing device, which stores the data value at the computing device. When a user is prompted to prove his or her ownership of the device, the owner can prove his or her ownership of the device in different manners by accessing the one or more services via a network (e.g., the Internet), or by providing the recovery key (e.g., obtained using another computing device) to the computing device.

As technology has advanced, computing devices have become increasingly commonplace in our daily lives. Many of these computing devices are portable, such as smartphones, tablet computers, and so forth. Although this portability provides many benefits, it also makes these devices the targets of thieves. Many computing devices provide little or no protection against theft, allowing thieves to easily sell or use these stolen devices.

Device theft protection associating a device identifier and a user identifier


An optical system includes a plurality of optical elements having finite refractive power and an electronic imaging device disposed at an image side of the optical system. At least one of the plurality of optical elements is made of resin, and an infrared-cut coating is applied to at least one face of the optical element that is made of resin.

1. Field of the Invention
The present invention relates to an optical system having a plurality of optical elements and to an imaging apparatus provided therewith, and relates to an optical system having a plurality of optical elements, such as lens components and prisms, for example, and to an imaging apparatus provided therewith, such as an imaging module for a digital camera or mobile telephone. More specifically, the present invention relates to an optical system in which an infrared-cut coating is applied to refractive surfaces of optical elements, to an optical filter, to a manufacturing method of an optical filter, and to an imaging apparatus provided therewith.
This application is based on Japanese Patent Applications Nos. 2004-235070, 2004-261301, 2005-033680, 2005-033684, and 2005-033694, the contents of which are incorporated herein by reference.
2. Description of Related Art
Recently, digital video cameras, digital cameras, and endoscopes provided with electronic-imaging optical systems including CCDs (charge coupled devices), CMOS (complementary metal oxide semiconductor) devices, etc. as imaging devices have been receiving attention.
Imaging devices formed of CCDs or CMOS devices have high sensitivity at wavelengths longer than the visible region of the spectrum (generally considered to be wavelengths from about 380 nm to about 750 nm), that is, in the so-called infrared region. Reduced resolution and image deterioration are caused by the received infrared light. Accordingly, in electronic imaging devices using imaging elements such as CCDs and CMOS devices, it is necessary to provide an infrared-cut filter or the like for removing infrared light in order to overcome this problem.
In general, the transmission characteristics of an infrared-cut filter are designed so that the transmittance of wavelengths above about 780 nm is as close as possible to zero.
Such infrared-cut filters include absorption-type filters in which the filter medium itself absorbs infrared light and reflection-type filters in which an infrared-cut coating that cuts infrared light is applied to the filter surface. In imaging apparatuses, such as digital cameras and video cameras, either of these types of filter, or both types of filter, is provided between a photographic lens and the imaging device.
Suitable methods for forming an infrared-cut coating include, for example, vacuum deposition and sputtering. In vacuum deposition, a material to be vaporized is thermally vaporized in a high vacuum and is deposited on a substrate to form a thin film. On the other hand, in sputtering, a high-energy atoms or molecules are made to collide with the material to be vaporized (target) and the atoms thrown off are deposited on a substrate to form a thin film.
An example of the transmittance-versus-wavelength characteristic of an absorption-type infrared-cut filter is shown in FIG. 36, and an example of the transmittance-versus-wavelength characteristic of a reflection-type infrared-cut filter is shown in FIG. 37. FIG. 36 shows the wavelength characteristic of an absorption-type infrared-cut filter available from Hoya Corporation (CD5000, thickness 0.45 mm). FIG. 37 is an example of the wavelength characteristic obtained when a 44-layer coating is formed on one surface of a flat filter.
When an infrared-cut filter, of either the absorption type or the reflection type, is disposed as described above, in order to ensure sufficient physical strength of the filter, the thickness must be at least 0.3 mm. Also, since it is necessary to maintain a certain spacing between the filter and lenses on either side thereof, there is a problem in that the overall length of the optical system becomes too large.
In addition, since the infrared-cut filter is provided separately from the optical system, an additional cost is required.
In order to solve these problems, Japanese Unexamined Patent Applications Nos. HEI-5-207350 and 2002-277738, for example, disclose a technique for making the system more compact by applying a multilayer film infrared-cut coating to one of the lens surfaces in a camera optical system. Also, Japanese Unexamined Patent Application No. 2004-88181 discloses a technique where an infrared-cut coating is vacuum deposited on the lens surface of a single lens. Japanese Unexamined Patent Application 2004-139035 discloses a technique for reducing the cost required for forming films by applying an infrared-cut coating to one surface of multiple glass plano-convex lenses in a batch.
Japanese Unexamined Patent Application Publication No. 2003-029027 discloses an infrared-cut filter in which a multilayer film is formed on both surfaces of a substrate, an infrared-cut filter including a plurality of substrates and having a multilayer film disposed between the substrates, and so on. By using a plurality of multilayer films in this way, it becomes easier to make the transmittance characteristic from the visible region to start of the infrared region drop. Also, infrared-cut filters having such a characteristic can be stably produced.
Japanese Unexamined Patent Application Publication No. 2004-173139 discloses an optical filter in which an infrared-cut filter is sandwiched between a first optical low-pass filter and a second optical low-pass filter.
Japanese Unexamined Patent Application Publication No. 2004-254259 discloses an infrared-cut filter in which a multilayer film is formed on both surfaces of a substrate and an infrared-cut filter including a plurality of substrates and having a multilayer film disposed between the substrates. According to this infrared-cut filter, by cutting infrared light with a plurality of multilayer films, it is possible to obtain light having wavelength characteristics close to the human visual sensitivity characteristics, and the design degree of freedom can be improved.
However, the conventional technologies described above have the following requirements and problems.
First, as well as imaging devices such as digital cameras and video cameras, recently, other products incorporating the electronic-imaging optical systems described above have also become commercially available, such as mobile telephones, mobile information terminals (PDAs), notebook computers and so on, and there is a strong demand to reduce the thickness, weight, and cost of such products. Accordingly, there are increasing demands for electronic-imaging optical systems with reduced thickness, weight, and cost that can be incorporated into such products.
Second, when applying an infrared-cut coating, there is a certain amount of error in the film thickness of each layer from the design value due to environmental variations, such as changes in temperature, humidity, and pressure. Therefore, as disclosed in, for example, Japanese Unexamined Patent Application Publication No. HEI-5-207350, the film thickness errors are compounded when forming a multilayer film on a lens surface. Generally, in an infrared-cut coating, a large number of layers is required to obtain the desired wavelength characteristics compared to a regular antireflection (AR) coating. Therefore, the film thickness error is larger than in an AR coating, and defective products are often produced, resulting in the problem of decreased yield.
Furthermore, when using a reflection-type infrared-cut filter in which an infrared-cut coating for cutting infrared light is applied to the filter surface, a known problem is that the wavelength region that is cut differs when the light is incident perpendicularly and when it is incident at an angle. Therefore, when the infrared-cut filter is combined with a coaxial optical system that is compact in the optical-axis direction, the angle of incidence of light tends to be different between the central region and the distal regions of the infrared-cut filter, resulting in the problem that color nonuniformity occurs at the central region and the distal regions in an image acquired by the CCD or CMOS device.
In an absorption-type infrared-cut filter in which the filter material absorbs infrared light, there are almost no variations in the infrared-cutting characteristics due to the incidence angle of the light, unlike reflection-type infrared-cut filters; however, the infrared-cutting characteristics do vary depending on the filter thickness. In other words, if the filter is made thicker, more infrared light can be cut, but then it becomes difficult to reduce the thickness of the imaging optical system. Conversely, if the filter is made thinner, the imaging optical system can be reduced in thickness, but there is a drawback in that the amount of infrared light that can be cut is small.

Optical filter, method of manufacturing optical filter, optical system, and imaging apparatus


A utility stand accommodates and/or holds washing implements. The utility stand includes a tray, a hose receptacle and an open frame. The tray is defines at least one recess for accommodating washing implements and other useful items. The open frame includes a base, a first and second support leg and a first and second support assembly. The support legs and the support assemblies are pivotally connected to the tray such that the open frame is collapsible from an upright position for use and a collapsed position for storage.

Washing a car is a labor-intensive act that requires numerous tools. Typically, hoses, soaps, sponges and other common washing implements are utilized when washing a car. Notably, the various tools are not used all at once, but rather are used, for the most part, in a sequential order. For example, a car washer is likely to set down the soap and sponge after applying the soap to the car while he or she rinses the soap off. Placing implements that are not being used on the ground can be troublesome and tends to dirty the implements. The car washer must also often search to find the implements and repeatedly bend down to pick them up. In cases where bending over is physically difficult for the user, such repeated action can become extremely unpleasant, if not impossible. In addition, utility stands are often cumbersome. Because storage space is often at a premium, utility stands are difficult to store because of their weight, lack of mobility and/or considerable footprint.
Therefore, it is desirable to provide a utility stand that overcomes the above-mentioned disadvantages in the prior art.


A method of manufacturing a crystal device includes applying substantially simultaneously a first light that is absorbed by a crystal plate and excites an energy level of a substance constituting the crystal plate from a ground state to a first excited state, and a second light that excites the energy level of the substance constituting the crystal plate from the first excited state to a second excited state to generate an ablation, thereby forming one or more grooves in a predetermined pattern on the crystal plate.

1. Technical Field
The present invention relates to a method for manufacturing a crystal device, and more specifically to a method for manufacturing a crystal device that can be made more easily.
2. Related Art
Conventionally, crystal oscillators are widely used as a source of clock signals in various electronic devices. The oscillation frequency of a crystal oscillator is determined by the resonance frequency of the crystal unit contained in the crystal oscillator. Examples of these crystal units include a convex or bevel crystal piece with a thickness increasing toward its center, prepared by the edges of an AT-cut crystal plate being processed to be curved surfaces. For example, JP-A-11-298278 discloses a convex crystal piece. These convex or bevel crystal units have a thick central portion to concentrate the vibration in the central portion of their crystal pieces, making efficient vibration with less energy possible. Also, in general, crystal units (i.e., crystal pieces) with the aforementioned shape are manufactured by polishing.

Method for manufacturing a crystal device


A test and measurement instrument includes a coefficient storage facility coupled to a programmable filter. The coefficient storage facility is configured to store at least two pre-determined filter coefficient sets, and configured to pass a selected one of the at least two pre-determined filter coefficient sets to the filter based on a measurement derived using a compensation oscillator. The measurement may include clock delay and clock skew. In some examples the test and measurement instrument may additionally adjust clock delay and/or clock skew in addition to selecting appropriate filter coefficients.

This disclosure relates to test and measurement instruments and, more particularly, to calibration of test and measurement instruments including one or more asynchronous time-interleaved digitizers, which use harmonic mixing for reducing noise.
Useable bandwidths of test and measurement instruments, such as digital oscilloscopes, can be limited by an analog to digital converter (ADC) used to digitize input signals. The useable bandwidth of an ADC can be limited to the lesser of the analog bandwidth or one half of a maximum sample rate of the ADC. Various techniques have been developed to digitize higher bandwidth signals with existing ADCs. One such technique is described in the above-referenced patent and applications, which includes splitting an input signal into a number of split signals each including substantially all of the bandwidth of the input signal. Then the split signals are respectively mixed with harmonic mixers and digitized. The digitized, split signals can be recombined to make a reconstructed input signal. This technique is referred to as ATI, or an Asynchronous Time Interleaved system.
In the event of interleaving errors due to analog mismatch of such a system, hardware adjustments can be made for mixing clock amplitude and phase. The adjustments can also be calibrated to minimize interleave mismatch spurs. Alternatively, or in addition, hardware mismatches can be characterized, and a linear, time-varying correction filter may be used to cancel the interleave spurs.
Previously, such calibration occurred at the factory before an instrument is shipped to a customer. Although the instruments are initially factory calibrated, hardware performance may drift from their calibrated state based on environmental conditions at runtime, such as temperature and humidity. Calibrating for a particular hardware state of such a sensitive device, however, requires access to a signal source that spans the full frequency range of the internal digitizer. The built-in calibration oscillators described in the '373 application, however, are not tunable over the entire range of the potential signal sources. Therefore, calibration of systems having a built-in calibration oscillator that does not span the entire range of potential signal sources suffers.
Embodiments of the invention address these and other limitations.

Calibration for test and measurement instrument including asynchronous time-interleaved digitizer using harmonic mixing