A sludge drying system using exhaust air from a furnace in a direct heat, rotary drum dryer to simultaneously dry and pelletize the sludge. The dried sludge particles exiting the dryer is entrained in the exhaust air. The sludge particles are separated from the exhaust air and then classified according to size. The under sized particles are recycled back to a mixer for mixing with incoming wet sludge. The oversized particles are conveyed to a crusher or mill for reducing the oversized particles down to the desired product size. The medium-sized particles can be selectively directed to be recycled with the undersized particles or collected as product. The exhaust air is treated in a treatment section, and then divided into two exhaust air streams or portions. A first portion of the exhaust air is discharged into the environment, while the second, larger portion of the exhaust air is recycled back to the furnace to be used to dry the sludge in the drier.

1. Field of the Invention
This invention relates to thermally treating mechanically dewatered sludge from municipal wastewater treatment plants, pulp and paper mills, oil refineries, food processing plants, or pharmaceutical manufacturing plants for removing water from fibrous suspensions. More specifically, this invention relates to a sludge drying system for producing granular particles or pellets to be used as fertilizer, and to a classifying system for pellet separation.
2. Description of the Prior Art
Typically, sludge from a municipal wastewater treatment plant or paper mill is first mechanically dewatered. The mechanically dewatered sludge is then fed to a sludge drying plant which utilizes heated air in a rotating drying drum. Dried sludge is pelletized and can be either sold as fertilizer or disposed of as permitted by restricting regulations.
Many processes have been proposed for thermally treating mechanically dewatered sewage sludge in a drying system. One such process is described in VSA - Dokumentation, "Klarschlammbehandeln" by U. Keller (1981) in which large or oversized dried sludge pellets are crushed and mixed with the undersized pellets, and then recycled for mixture with incoming dewatered sludge. This process has the drawback that large quantities of oversized pellets are crushed into smaller size particles or fines which are then recycled. This process requires high energy input for the crusher and also for the transporting devices. Also this large quantity of crushed sludge particles has to be heated in the dryer which also results in an increase energy consumption for the entire system.
This invention addresses these problems in the art as well as other problems in the art which will be apparent to those skilled in the art once given this disclosure.


A power gating circuit and a control method for power gating switch thereof are provided. The power gating circuit includes a first switch, the power gating switch, a pre-charge circuit, and a control circuit. A first terminal and a second terminal of the first switch are coupled to a first voltage and the control terminal of the power gating switch, respectively. A first terminal and a second terminal of the power gating switch are coupled to a second voltage and a function circuit, respectively. An input signal defines a powered period of the function circuit. According to the input signal, the pre-charge circuit pre-charges the control terminal of the power gating switch during the first sub-period of the powered period, and the control circuit controls the first switch to charge the control terminal of the power gating switch by the first voltage during the second sub-period of the powered period.

Field of the Disclosure
The disclosure relates to a power gating circuit, and relates particularly to a power gating circuit and a control method for a power gating switch thereof.
Description of Related Art
Along with portable products (for example, a cell phone, a digital camera, a notebook computer and the like) becoming increasingly widespread, how to reduce the power consumption of the portable products has currently become a significantly important task.
One of the methods for reducing the power consumption of a circuit is to use a power gating circuit. The power gating circuit may control the power supply situation of the power supply circuit to the function circuit. When a function circuit enters power saving mode, the power gating circuit may make the power supply circuit stop supplying power to the function circuit, and may resolve the sub-threshold current leakage problem of the function circuit blocks, and lowering the overall power consumption.
FIG. 1 is a circuit diagram of a conventional power gating circuit 100. The power gating circuit 100 in FIG. 1 is implemented by connecting a plurality of inverters INV11, INV22, INV33 and power gate switches SWP11, SWP12 in series. An input signal VS defines a powered period of a function circuit 10. Whether to allow a voltage provided by a voltage source VDD1 to pass through the power gating switch SWP11 to supply power to the function circuit 10 may be determined by controlling an input signal VS. When the function circuit 10 enters power saving mode, the power gating circuit 100 may make the voltage source VDD1 stop supplying power to the function circuit 10. When the power gating switch SWP11 cuts off the transmission path between the voltage source VDD1 and the function circuit 10, and/or when the power gating switch SWP12 cuts off the transmission path between the ground voltage GND and the function circuit 10, the power consumption of the function circuit may be reduced effectively.
However, the power gating switches SWP11, SWP12 require a substantially large path area to transmit large amounts of current to the function circuit 10 when the power gating switches SWP11, SWP12 of the power gating circuit 100 turns on. In order to turn on the power gating switches SWP11, SWP12 which have large path areas, a conventional power gating circuit is required to consume a large current of a high voltage source VPP, referred to as a wake up current. A voltage of the voltage source VPP typically is greater than the voltage of the voltage source VDD1. In order to supply the large amounts of current, a large voltage pump and a capacitor needs to be disposed on the voltage source VPP. Therefore, how to develop a circuit to reduce the large current of the voltage source VPP that is consumed when switching the power gating circuit effectively is a problem which needs to be solved.

Power gating circuit and control method for power gating switch thereof


The phase-frequency detector may include a first flip-flop configured to generate a first signal, the first signal transitioning to a first logic level in response to a first edge of a first input signal and transitioning to a second logic level in response to a delayed reset signal and a second flip-flop configured to generate a second signal, the second signal transitioning to the first logic level in response to a second edge of a second input signal and transitioning to the second logic level in response to the delayed reset signal. The phase-frequency detector may further include a first delay unit configured to delay a reset signal to generate the delayed reset signal and a second delay unit configured to delay the reset signal to generate an output control signal for adjusting at least one of the first and second signals.

1. Field of the Invention
Example embodiments of the present invention relate generally to a phase-locked loop and method thereof and a phase-frequency detector and method thereof, and more particularly to a phase-locked loop and a phase-frequency detector with reduced performance errors and methods thereof.
2. Description of the Related Art
A phase-locked loop (PLL) and/or a delay-locked loop (DLL) may be employed in conventional digital communication systems to transmit data at higher speeds while maintaining a reliable data transfer. In the phase-locked loop, a phase-frequency detector may compare a phase of a reference signal with a phase of a signal received from a voltage-controlled oscillator (VCO). An output Of the phase-frequency detector may be applied to a charge pump to generate a phase detection signal varying in accordance with the phase difference between the reference signal and the VCO signal. A loop filter may perform a low pass filtering operation on the detected phase detection signal to generate a control voltage signal, which may be output to the VCO. The VCO may generate the VCO signal based on the control voltage signal received from the loop filter. The VCO signal may be divided by a loop divider and output to the phase-frequency detector to be compared with the reference signal.
FIG. 1 is a circuit diagram illustrating a conventional phase-frequency detector. Referring to FIG. 1, the conventional phase-frequency detector may include a first flip-flop 10, a second flip-flop 12 and an AND gate 14. The first flip-flop 10 may generate an up signal UP based upon a detection of a rising edge of the reference signal REF. The second flip-flop 12 may generate a down signal DN based upon a detection of a rising edge of a comparison signal FDB. The AND gate 14 may perform an AND operation of the up signal UP and the down signal DN to generate respective reset signals for the first and second flip-flops 10 and 12. The up signal UP may control an up current source of a charge pump 20 and the down signal DN may control a down current source of the charge pump 20.
A phenomenon referred to as a "dead zone" may occur during an operation of the conventional phase-frequency detector. If a phase difference between two input signals is low, the up signal UP may not reach a first logic level (e.g., a higher logic level or logic "1") due to the time required to charge a load capacitor of a switch (e.g., one or more of switches S1 and S2 which may be implemented as field effect transistors (FETs)) of the charge pump 20 (e.g., the up signal UP may not exceed a threshold voltage of the switch). Thus, the up signal UP and the down signal DN may instead be set to a second logic level (e.g., a low logic level or logic "0"). The dead zone may occur where the phase-frequency detector may not produce the up signal UP and the down signal DN for charging and discharging the charge pump despite the presence of a phase difference between the two input signals.
Occurrences of dead zones may be reduced by decreasing a rising time (e.g., a time period required to transition to the first logic level) of the up signal UP and the down signal DN output from the phase-frequency detector. As discussed above, the switches S1 and S2 of the charge pump 20 may be implemented as FETs, and reduction in capacitor loads associated with FETs may be difficult to achieve.
FIG. 2 is a graph illustrating a detected current based on a phase difference between two input signals received by the conventional phase-frequency detector in FIG. 1.
FIG. 3 is a circuit diagram illustrating another conventional phase-frequency detector. Referring to FIG. 3, another conventional phase-frequency detector may be configured similarly to the above-described phase-frequency of FIG. 1. However, this phase-frequency detector may further include a delay unit 16 for delaying a reset signal by the AND gate 14 for resetting the first and second flip-flops 10 and 12. Two input signals REF and FDB (e.g., a reference signal and a feedback signal, respectively) may be reset to the second logic level (e.g., a low logic level or logic "0") such that the up signal UP and the down signal DN may be maintained at the first logic level (e.g., a high logic level or logic "1") for a time period sufficient to reduce the dead zone.
FIG. 4 is a graph illustrating a detected current based on a phase difference between two input signals received by the conventional phase-frequency detector in FIG. 3.
Referring to FIG. 4, if both the up signal UP and the down signal DN are set to the first logic level (e.g., a high logic level or logic "1"), the switches S1 and S2 may each be turned on such that an "operating point" of the phase-frequency detector may move towards a centered position (e.g., see the directions indicated by the arrows illustrated in the graph of FIG. 4), which may thereby cause a glitch in the phase detection. If the delay added to the reset signal is increased (e.g., by the delay unit 16), a turn-on time of the switches S1 and S2 may likewise increase, which may thereby increase a frequency and/or duration of glitches.
Conventional phase-frequency detectors may be adapted to reduce pulse widths of the up signal UP and the down signal DN by controlling an output of the up signal UP and the down signal DN in response to the reset signal. However, if two input signals have substantially the same phases (e.g., where the phase difference may be close to zero), lower (e.g., minimum) pulse widths of the up signal UP and the down signal DN may be determined. Therefore, the dead zone may occur where the delay characteristics of the output gate are lower because the pulse widths of the up signal UP and the down signal DN may be set irrespective of the capacitance of the charge pump (e.g., charge pump 20). Further, as discussed above, adding delay (e.g., with the delay unit 16) to the output gate may reduce the dead zones at the expense of generating glitches or errors in the phase detection of the phase-frequency detector.

Phase-locked loop and method thereof and a phase-frequency detector and method thereof


Communication between a controller and a set of automated vehicles is improved by use of an RF link that employs a high frequency spread spectrum modem that establishes a low noise link in a high noise industrial environment and also shares the relevant frequency range with a wireless telephone system.

The field of the invention is that of RF communication between a controller and a set of autonomous automated vehicles transporting materials within a building or other location; in particular transporting a load along a track in a remotely controlled vehicle.
In the field of material transport through automated vehicles, it is necessary for a controller to communicate with individual ones of the vehicles to tell it to start, follow a certain path to a destination and to unload.
Communication between the controller and the individual vehicles is plagued by noise and other interference.
In the past, the RF link was completed with low frequency wireless communication, typically not in compliance with an FCC standard.
Various suppliers use infra-red optical links, ethernet or other relatively low RF frequency communications.
These systems suffer from cross talk between different vehicles, loss of signal, short range (line of sight) or a requirement of physical contact between the vehicle and an antenna or other means of carrying the control signals.
In one example, cross talk between individual vehicles results in vehicle A obeying a command to stop that was intended for vehicle B, with the result that vehicle A is stranded in a place where it does not belong.
In another example, vehicle A could obey a command to start that was received at an inopportune time—e.g. during a loading process.
Similarly, in a common approach to vehicle control, the vehicle is not left alone to proceed to a destination, but is periodically told to continue moving, with the fail-safe response to stop (for safety reasons). If contact is lost with the controller, the vehicle will be stranded between a start location and an end location.
Optical systems require that there be a straight line between the controller or relay points for controller signals and the sensor on the vehicle. In a dirty factory environment, the sensor may become coated with dust and unable to sense signals.
Conventional present-day systems use open-loop technology, in which the vehicle is told to start moving and then continues until it reaches its destination or suffers a malfunction.
Control signals are conventionally broadcast throughout a relatively large factory space, with potential for causing interference with other equipment that responds to a signal meant for the material handling system.
Since the controller doesn't know where individual vehicles are, collision avoidance requires a conservative margin of safety such as permitting only one vehicle at a time to operate within a relatively large area.
The art could benefit from a closed-loop system that is resistant to noise and has a high degree of separation for simultaneous operation.

Automation system using wireless high frequency

International Business Machines Corporation


A cushion member assembly includes an attachment fastener having deflecting first and second arms curving toward a planar flange, and a neck region connecting the first and second arms to the planar flange. A cushion member includes a slot in a body first portion first end and a body second portion having a hollow chamber. A first bore extends into the body first portion from the slot. A second bore has a diameter larger than a first bore diameter and substantially equal to a first and second arm spaced width. A surface separates a cavity defined by the second bore from the first bore. The arms initially deflect toward each other during entrance into the first bore and outwardly rebound in the second bore directly contacting the surface. The first and second arms in contact with the surface resist removal of the attachment fastener from the cushion member.

This section provides background information related to the present disclosure which is not necessarily prior art.
Automobile trunk lids are normally manually opened with the assistance of a mechanism including opposed trunk arms that are connected between the trunk lid and panel or structure of the vehicle body. Trunk lids may have their motion assisted to reduce the lifting force required by the operator and/or may contact rubber or resilient material bumpers at the end of arm travel to stop trunk lid travel. At present, if a vehicle trunk lid is opened too quickly, and particularly when newer design reduced resistance trunk lid mechanisms are used, the lid will rebound or bounce off away from the rubber stops used to absorb and dampen this travel, and can either block access to the trunk, requiring a second opening action, or strike the operator.


This invention is based upon the discovery that a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol is effective for polymerizing norbornene-functional monomers into polynorbornene-functional polymers. It has been further discovered that this catalyst system is more effective in polymerizing certain norbornene-functional monomers that are difficult to polymerize, such as norbornene ester monomers, than prior art catalyst systems. The activity of the catalyst systems of this invention can be further improved with respect to polymerizing some monomers by including a Lewis acid and/or a ligand, such as a phosphine or a carbene, in the system. In any case, the catalyst systems of this invention offer the advantage of being soluble in a wide variety of solvents, relatively inexpensive, and capable of polymerizing many norbornene-functional monomers that are difficult to polymerize with conventional catalyst systems. The subject invention more specifically discloses a catalyst system that is especially useful for the polymerization of norbornene-functional monomers which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol. The present invention also reveals a process for synthesizing a norbornene-functional polymer which comprised polymerizing a norbornene-functional monomer in a solvent in the presence of a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a member selected from the group consisting of fluorinated alcohols, fluorinated acids, and ionic liquids, wherein the catalyst system is void of alkyl aluminum compounds.

A process for the synthesis of polynorbornene or "poly(bicyclo[2.2.1]hept-2-ene)" or polyNB for brevity is reported in U.S. Pat. No. 2,721,189. However this original material was found to contain two types of polymers, one brittle, the other thermoformable and "drawable". The brittle polymer was later found to be a low molecular weight saturated polymer which was termed an addition type polymer; and, the thermoformable polymer was shown to be formed by ring opening metathesis polymerization (ROMP). A ROMP polymer has a different structure compared with that of the addition polymer in that (i) the ROMP polymer of one or more NB-functional monomers, contains a repeat unit with one less cyclic unit than did the starting monomer, and, (ii) these are linked together in an unsaturated backbone characteristic of a ROMP polymer and is shown below.

Despite being formed from the same monomer, an addition-polymerized polyNB is clearly distinguishable over the polymer made by ROMP polymerization. Because of the different (addition) mechanism, the repeating unit of the former has no backbone carbon-carbon double bond unsaturation as shown below:

The difference in structures of ROMP and addition polymers of NB-functional monomers is evidenced in their properties, e.g., thermal properties. The addition type polymer of NB has a high glass transition temperature (Tg) of about 370° C. The unsaturated ROMP polymer of NB exhibits a Tg of about 35° C., and exhibits poor thermal stability at high temperature above 200° C. because of its high degree of carbon-carbon unsaturation.
Over the years, reaction conditions have been optimized so as to enable one to choose, and selectively make, either the low molecular weigh addition polymer, or the ROMP polymer. For instance, U.S. Pat. No. 3,330,815 indicates that only the addition polymer is synthesized with TiCl4/Et2AlCl or Pd(C6H5CN)2Cl2, under particular conditions, except that the polymers produced are only those in the molecular weight range from 500 to 750 in which range they are too brittle for any practical application.
Addition polymers of norbornene have been shown to be produced with "zirconocene type" catalysts such as those taught by Kaminsky et al. These polymers have been found to be a highly crystalline form of a "norbornene-addition polymer", that is, an addition polymer of a NB-functional monomer, which is totally insoluble, and reportedly does not melt until it decomposes at about 600° C. (under vacuum to avoid oxidation). It is therefore unprocessable (W. Kaminsky et al., J. Mol. Cat. 74, (1992), 109; W. Kaminsky et. al. Makromol. Chem, Macromol. Symp., 47, (1991) 83; and W. Kaminsky, Shokubai, 33, (1991) 536.). An added distinguishing characteristic of the zirconocene catalyst system is that it catalyzes the copolymerization of ethylene and norbornene. In such copolymers, the amount of NB incorporated into the ethylene/NB copolymer can be varied from high to low (W. Kaminsky et. al. Polym. Bull., 1993, 31, 175).
The polymer formed with a zirconocene catalyst can incorporate ethylene (or compounds containing ethylenic unsaturation at a terminal end thereof) in its backbone, randomly, whether in runs of a multiplicity of repeating units, or even a single unit. It should also be noted that the ionic metallocene catalysts, such as zirconocenes and hafnocenes, use metals from Group IVB as the cation with a compatible weakly coordinating anion.
Research has continued toward the production of a melt-processable addition polymer of a NB-type monomer, and is the subject of an on-going effort. By "melt-processable" it is meant that the polymer is adequately flowable to be thermoformed in a temperature window above its glass transition temperature (Tg) but below its decomposition temperature. Norbornene monomer, bicyclo[2.2.1]hept-2-ene or "NB" for brevity, and substituted embodiments thereof, such as ethylidenenorbornene or decylnorbornene, and particularly those monomers of NB having at least one substituent in the 5- (and/or 6-) positions are commonly referred to as "norbornene-functional monomers." The foregoing monomers are characterized by containing a repeating unit resulting from an addition polymerized derivative of bicyclo[2.2.1]hept-2-ene. A first NB-functional monomer may be polymerized by coordination polymerization to form (i) an addition homopolymer; or, (ii) with a second NB-functional monomer, either one (first or second) of which is present in a major molar proportion relative to the other, to form an addition NB-functional copolymer; or, (iii) with a second monomer which is not an NB-functional monomer, present in a minor molar proportion relative to the first, to form an addition copolymer with plural repeating units of at least one NB-functional monomer.
A few years ago the reactivity of cationic, weakly ligated, transition metal compounds was studied in the polymerization of olefins and strained ring compounds, (A. Sen, T. Lai and R. Thomas, J. of Organometal. Chemistry 358 (1988) 567–568, C. Mehler and W. Risse, Makromol. Chem., Rapid Commun. 12, 255–259 (1991)). Pd complexes incorporating the weakly ligating CH3CN (acetonitrile) ligand in combination with a weakly coordinating counteranion could only be used with aggressive solvents such as acetonitrile or nitromethane. When Sen et al used the complexes to polymerize NB, a high yield of a homopolymer which was insoluble in CHCl3, CH2Cl2 and C6H6, was obtained.
The identical experimental procedure, with the same catalyst and reactants, when practiced by Risse et al used one-half the molar amount of each component. Risse et al reported the synthesis of a poly-NB homopolymer which had a number average molecular weight (Mn) of 24,000. In other runs, using different ratios of NB to Pd2+ compound, poly-NBs having number average molecular weights of 38,000 and 70,000 respectively with narrow polydispersities Mw/Mn in the range from 1.36 to 1.45, and viscosities in the range from 0.22 to 0.45 dL/g were made. A homopolymer which had a viscosity of 1.1 was synthesized, which upon extrapolation from the molecular weight data given for the prior runs, indicates the weight average molecular weight (Mw) was over 1,000,000. See Mehler and Risse Makromol. Chem., Rapid Commun. 12, 255–9 (1991), experimental section at the bottom of page 258 and the GPC data in Table 1 on page 256. The polymers were soluble in 1,2-dichlorobenzene in which Risse et al measured molecular weights by GPC (gel permeation chromatography) and viscometry, as did Maezawa et al in EP 445,755A, discussed below.
Maezawa et al disclosed the production of high molecular weight NB polymers with a two-component catalyst system. The disclosure states that the polymer is preferably formed in the molecular weight range from 100,000 to 10,000,000. The manner of obtaining the desired molecular weight is shown to be by terminating the polymerization reaction after a predetermined period. Such termination is effected by decomposing the catalyst with an external terminating agent such as acidified methanol, which is added to the reaction to stop the polymerization. There is no internal control of the molecular weight within a predetermined range by an agent that does not deactivate the catalyst.
Specifically, three known methods of controlling the molecular weight are suggested: (i) varying the amount of the transition metal compound used; (ii) varying the polymerization temperature; and (iii) using hydrogen as a chain transfer agent "CTA" (see page 9, lines 20–23 of the EP 445,755A disclosure) as suggested by Schnecko, Caspary and Degler in "Copolymers of Ethylene with Bicyclic Dienes" Die Angewandte Makromolekulare Chemic, 20 (1971) 141–152 (Nr.283). Despite the foregoing suggestions, there is no indication in EP 445,755A that any of them were effective as is readily concluded from the illustrative examples in the specification. As stated in their illustrative Example 1 in which the catalyst included a combination of nickel bisacetylacetonate Ni(acac)2 and methaluminoxane ("MAO"), a polyNB having Mw of 2.22×106 (by GPC) was formed. As shown in Table 1 of EP 445,755A, only Examples 5, 6 and 7, in which the (triphenylphosphine) Ni-containing catalysts were used, made homopolymers with weight average molecular weights of 34,000; 646,000; and 577,000 respectively. These nickel catalysts with a triphenylphosphine ligand, are shown to have relatively lower productivity than the biscyclooctadienylnickel (see Example 3) and biscyclopentadienylnickel (Example 4) which were also used.
Allylnickelhalides alone (no Lewis acid cocatalyst) have been used to produce polyNB. The molecular weights of the NB polymer produced in these studies were within the range of 1000 to 1500 (L. Porri, G. Natta, M. C. Gallazzi Chim. Ind. (Milan), 46 (1964), 428). It had been thought that the low yields and the low molecular weights of the polyNB were due to deactivation of the catalysts.
EP 504,418A discloses the use of a nickel catalyst as a transition metal equivalent to zirconium for the production of high molecular weight norbornene polymer with a three component catalyst system (see Example 117). The three-component catalyst was made in situ by combining triisobutylaluminum; dimethylanilinium tetrakis(pentafluorophenyl)borate; and, Ni(acac)2 in toluene. The polymer recovered had a weight average molecular weight (Mw) of 1.21×106 and a polydispersity of 2.37. Though essentially the entire specification is directed to the copolymerization of cycloolefins with α-olefins using zirconium-containing catalysts, Okamoto et al did not react norbornene and α-olefin with a nickel catalyst. Nowhere in the EP 504,418A specification is there a teaching that the use of an α-olefinic CTA will control molecular weight. There is no teaching of a polymer with a terminal olefinic end-group. Nor is there any teaching that an α-olefin would do anything but copolymerize.
The failure to recognize that an α-olefin might function as a CTA, with or without the presence of an alkylaluminum cocatalyst, was understandable since there existed a large body of work related to the copolymerization of cycloolefins with α-olefins, and in none of such polymerizations was there any disclosure that the α-olefin might function as an effective CTA. Further, the great reactivity of ethylene or propylene buttressed an expectation that copolymerization, not chain transfer, is the logical and expected result.
Acyclic olefins, such as 1-hexene, are known to be effective for utilization as a CTA in the ROMP of cyclic olefins, to reduce molecular weight via a cross-metathesis mechanism. ROMP involves a metal carbene (or metal alkylidene) active center which interacts with the cyclic olefin monomer to afford a metallocycloalkane intermediate. A repeating unit contains a carbon-carbon double bond (—C═C—) for every carbon-carbon double bond in the monomer. How effectively the acyclic olefin reduces the molecular weight of the copolymer formed depends on the structure of the olefin and on the catalyst system (K. J. Ivin, Olefin Metathesis, Academic Press, 1983). In contrast, addition (or vinyl type) polymerization of olefins and diolefins involves the insertion of the monomer into a metal-carbon a-bond, as in Ni—C, or Pd—C. Despite the many disclosures relating to the formation of copolymers of NB-type monomers, and the well-known fact that an olefin is an effective chain transfer agent in a ROMP polymerization, it will now be evident why the difference in the mechanisms of chain termination failed to suggest the use of an olefin as a chain transfer agent in the copolymerization taught herein.
U.S. Pat. No. 5,571,881 discloses addition polymers derived from norbornene-functional monomers that are terminated with an olefinic moiety derived from a chain transfer agent selected from a compound having a terminal olefinic double bond between adjacent carbon atoms, excluding styrenes, vinyl ethers, and conjugated dienes wherein at least one of said carbon atoms has two hydrogen atoms attached thereto. The addition polymers of described in this patent are prepared from a single or multicomponent catalyst system including a Group VIII metal ion source. These catalyst systems are unique in that they catalyze the insertion of the chain transfer agent exclusively at a terminal end of the polymer chain. U.S. Pat. No. 5,571,881 more specifically discloses a process for controlling the molecular weight of an addition polymer comprising repeating units polymerized from one or more norbornene-functional monomers, said process comprising reacting a reaction mixture comprising at least one norbornene-functional monomer, a solvent for said monomer and an effective amount of a single or multicomponent catalyst system each comprising a Group VIII transition metal source and a chain transfer agent selected from a compound having a terminal olefinic double bond between adjacent carbon atoms, excluding styrenes, vinyl ethers, and conjugated dienes, and at least one of said adjacent carbon atoms has two hydrogen atoms attached thereto.

This patent is subject to a terminal disclaimer.

Catalyst for polymerization of norbornene


The present invention is a canopy structure comprising a frame and a canopy. The frame comprises a plurality of arms and legs, where each of the arms extends outwardly from a central connecting member to a leg, each arm and leg being joined by a leg connecting member. Preferably, each leg is telescopic and is lockable and the central connecting member preferably comprises a releasable locking mechanism. The present invention further comprises a mechanism by which the canopy surface can be tilted to angles relative to the ground.

Many foldable and collapsible structures for providing shelter from the weather or elements are already commercially available. Most of these products provide a shelter with some sort of domed or pointed roof. Many of these structures are complex and cumbersome in construction.
A drawback to the commonly available portable structure is the massive size and weight of the main supporting structure, thereby making them heavy, cumbersome and generally difficult to transport, especially for a single individual. Many of the collapsible structures that are portable are not small enough to be practical for personal or small group use. Additionally, due to the weight and size, some canopies require multiple people for assembly.
A problem with conventional structures is the inability of the canopies to adapt or accommodate for different circumstances. For many of these structures, the main objective is covering from the elements like rain or wind, and as such, typically the structure has some sort of peak for providing runoff from rain or additional supports to provide stability from wind. The construction to accommodate these situations is reinforced so as to make them rigid and not easily adapted or angled to adjust for the movement of the sun in relation to the user. In order to remain protected from the sun, the user has to move under the structure or move the structure base for better placement of shade. The inability of these canopies to adapt can frustrate the end use of providing shade. In addition, the size and nature of these structures makes them less accessible for use at a beach or for small gatherings where users prefer to be relatively unencumbered by bulky or heavy materials.
As such, it would be of great utility to have a portable canopy structure, one that is lightweight and sturdy, and can be erected and taken down by a single user, and one that would be capable of being adjusted so that the canopy can be made to adapt to the movement of the sun.


An electrical connector assembly is provided for electrically connecting a pair of generally coplanar printed circuit boards. The assembly includes a pair of hermaphroditic connectors adapted for mating in either opposite direction generally perpendicular to the plane of the circuit boards. Each connector includes a housing having a plurality of spaced-apart ribs defining respective spaces between immediately adjacent ribs. The ribs of each connector are interleaved with the ribs of the other connector when the two connectors are mated. A plurality of terminals are mounted on each housing and have rounded hermaphroditic contact portions on the same sides of the ribs so that the contact portions on one connector facingly engage the contact portions on the other connector when the connectors are mated in either opposite direction generally perpendicular to the plane of the circuit boards.

Complex electronic equipment which uses semiconductor technology relies heavily on electrical interconnection systems for interconnecting a pair of printed circuit boards. A printed circuit board typically includes a relatively rigid substrate having a circuit pattern printed thereon and mounting a plurality of circuit devices. This subassembly, in turn, is mounted within a larger apparatus and electrically connects a wide variety of other components or modules.
Electrical connectors are used to relatively mount and interconnect a pair of circuit boards in a variety of configurations or orientations. For instance, an electrical connector may be mounted on a main printed circuit board, often called a "mother" board, and the connector receives a "daughter" board in an edge-wise configuration. In some configurations, a pair of circuit boards are interconnected in a generally coplanar relationship. In fact, some electrical connector assemblies allow for the pivoting of one board relative to the other board at adjacent edges of the boards. With circuit boards that are interconnected in an edge-wise, coplanar arrangement, it would be desirable to allow for interconnection of the boards in a direction generally perpendicular to the boards. Otherwise, if the boards are interconnected in the plane of their eventual coplanar configuration, considerable space is required in the larger apparatus for moving the boards together in a single planar area.
In addition, electrical connectors for interconnecting a pair of circuit boards often are complex and expensive, involving one type of connector (such as a male or plug connector) mounted to one of the circuit boards, and still another type of connector (such as a receptacle connector) mounted on the other circuit board. It would be desirable to provide a simple hermaphroditic electrical connector that can be mounted on both circuit boards and still provide for interconnecting movement generally perpendicular to the eventual coplanar boards. The present invention is directed to satisfying these needs and solving the various problems involved in the design of simple and inexpensive electrical connectors for interconnecting printed circuit boards.

Hermaphroditic connector for printed circuit boards


A system for determining when a cleaning process has completed is disclosed. This system relies on an increase in the amount of gas in the processing chamber that occurs when the cleaning is complete. This increase in the amount of gas may be detected in several ways. In one embodiment, a downstream pendulum valve is used to maintain the pressure within the processing chamber at a predetermined value. An increase in the size of the opening in the pendulum valve is indicative of the amount of gas in the system. In another embodiment, a sensor may be used to monitor the pressure within the processing chamber, while the incoming and outgoing flow rates are held constant. An increase in the pressure is indicative of an increase in the amount of gas in the processing chamber. This increase in the amount of gas is used to terminate the cleaning process.

The fabrication of a semiconductor device involves a plurality of discrete and complex processes. These processes may take place within a processing chamber. Over time, residual materials become deposited on the walls of the processing chamber. For example, in the case of an etching process, the etching byproducts may be released from the semiconductor workpiece and contact an interior surface of the processing chamber.
Over time, the amount of residual material deposited on the interior surfaces may become problematic. For example, this residual material may detach from these interior surfaces and contaminate the semiconductor workpiece that is being processed.
Therefore, it is common to periodically conduct a cleaning process. Typically, after the semiconductor workpiece has been removed, a cleaning gas, which includes a halogen species, is introduced into the processing chamber. The halogen species interacts with the residual material to create gaseous materials, which can be expelled through the vacuum pump.
In certain embodiments, it is advantageous to perform the cleaning process for an optimal duration. If the duration of the cleaning process is too short, all of the residual material may not be removed from the interior surfaces. However, if the duration of the cleaning process is too long, the halogen species may begin to attack the interior surfaces themselves, causing pitting and creating metallic particles.
In some cases, optical emission spectroscopy (OES) is used to determine when the cleaning process is complete. When the residual material has all been removed, the amount of free halogen gas increases. Each compound emits light energy when it reverts to the relaxed state from the excited state. The spectrum of this light energy is related to the compound being excited. Thus, when the amount of the halogen gas increases, the peak value at the wavelength associated with that halogen gas increases. An OES system can recognize this increase in free halogen gas and terminate the cleaning process. Alternatively, a residual gas analysis (RGA) system may be used. These systems use the mass/charge relationship to determine the composition of gas in a low pressure environment. Again, the RGA system can detect an increase in the amount of free halogen gas and terminate the cleaning process.
However, OES and RGA systems are expensive and, in some cases, impractical. Therefore, it would be beneficial if there were a system to determine when a cleaning process is complete without the use of an OES or RGA system. Further, it would be beneficial if this system was as accurate as these other types of systems.

System for determining cleaning process endpoint


A PCM modem equalizer includes an RBS estimator and decision modulator in conjunction with an adaptive equalizer such as a conventional decision feedback equalizer (DFE). The RBS estimator and decision modulator receives error signals from the second summer in the equalizer, receives the estimated R signals from the first summer of the equalizer, and outputs a gain correction signal which is applied to the output of the reference generator before the reference generator output is applied to the feedback equalizer and the second summer. The methods of the invention are based on the recognition that the effects of RBS can be detected in the amplitude modulation of the main training sequence stream. The modulation will occur in a periodic repetitive pattern of length 6*T where T is the symbol interval. Therefore, the invention applies a corrective gain to the decision in each time slot in a periodic manner having the same period 6*T. For each time interval T.sub.k over a period of 6*T, the symbol present at the time interval is sampled and a respective corrective gain g(6k-j) is applied to it, where j has the values 0 through 5. The gain applied to each of the six time slots is adaptively updated over a training period until each of the six gain coefficients is optimized.

1. Field of the Invention
The present invention relates broadly to the field of telecommunications. More particularly, the present invention relates to a modem equalizer for a PCM modem where the modem equalizer will function properly in the presence of a robbed-bit signalling network.
2. State of the Art
With the ever-increasing importance of telecommunications for the transfer of data as well as voice, there has been a strong effort to increase data transfer rates over the telephone wires. Recently, the ITU-T adopted the V.34 Recommendation (International Telecommunication Union, Telecommunication Standardization Sector Recommendation V.34, Geneva, Switzerland 1994) which is hereby incorporated by reference herein in its entirety. The V.34 standard and subsequent amendments define modem operating speeds of 28.8 kbps up to 33.6 kbps, and the vast majority of modems being sold today adhere to the V.34 Recommendation. However, with the explosion in the use of the Internet, even at the V.34 transfer rates, downloading of large files available on the Internet can take long periods of time. Thus, recently, there has been a thrust to provide additional standards recommendations which will increase data transfer rates even further (note the TIA TR-30.1 PCM Modem ad hoc group and the ITU-T Study Group 16).
Recognizing that further increases in data rates is theoretically limited (see C. E. Shannon, "A Mathematical Theory of Communication," Bell System Technical Journal, 27:379-423, 623-656 (1948)), there have been various proposals to take advantage of the fact that much of the telecommunication network is now digital. For example, U.S. Pat. No. 5,394,437 to Ayanoglu et al., U.S. Pat. No. 5,406,583 to Dagdeviren, and U.S. Pat. No. 5,528,625 to Ayanoglu et al. (all assigned to AT&T/Lucent and all of which are hereby incorporated by reference herein in their entireties) all discuss techniques which utilize the recognition that the network is mostly digital in order to increase data transmission rates to 56 kbps and higher. Similarly, Kalet et al., "The Capacity of PAM Voiceband Channels," IEEE International Conference on Communications '93, pages 507-511 Geneva, Switzerland (1993) discusses such a system where the transmitting end selects precise analog levels and timing such that the analog to digital conversion which occurs in the central office may be achieved with no quantization error. PCT application number PCT/US95/15924 (Publication WO 96/18261) to Townshend (which is hereby incorporated by reference herein in its entirety) discusses similar techniques. All of the disclosures assume the use of PAM (pulse amplitude modulation) digital encoding technology rather than the QAM (quadrature amplitude modulation) currently used in the V.34 Recommendation. The primary difference between the AT&T technology and the Townshend reference is that the AT&T technology suggests exploiting the digital aspect of the telephone network in both "upstream" and "downstream" directions, while Townshend appears to be concerned with the downstream direction only. Thus, systems such as the ".times.2" technology of US Robotics which are ostensibly based on Townshend envision the use of the V.34 Recommendation technology for upstream communications. As will be appreciated by those skilled in the art, the technologies underlying the V.34 Recommendation, and the proposed 56 kbps modem are complex and typically require the use of high-end digital signal processors (DSPs).
One of the tasks of the modem is the task of equalizing incoming signals. Equalization is a technique used to compensate for distortion in analog signal lines. One of the distortions which is compensated for is Intersymbol Interference (ISI) which is described in more detail below. Prior to data communication, two communicating modems engage in a training sequence wherein the equalizers of the modem receivers are set to compensate for the quality of the analog signal line which links the modems. However, it has been found that training of the equalizer in the modem receiver is adversely affected if the connection between the receiving modem and the ultimate source of the received data includes both analog and digital signal lines. In particular, training is adversely affected by robbed bit signaling (RBS) introduced by the digital network into the digital data stream and by Digital Pad Attenuation (DPA) in the digital network.
RBS is a technique used in T1 network connections where the least significant bit of each nth data octet is replaced with a control bit by the network for control signalling. The frequency of robbed bits through a single T1 connection is one every sixth symbol. This "in-band" signalling is used to indicate things like "off-hook", "on-hook", "ringing", "busy signal", etc. RBS results in data impairment by changing transmitted bit values. When the data flowing through the network is digitized audio voice signals, a change in the least significant bit of some octets will introduce noise or distortion into the ultimate analog audio reproduction of the digitized voice signal. Nevertheless, this has been found to be acceptable for voice communications. When the data flowing through the network is digital data, however, RBS can have very serious consequences. For this reason, when data is sent through a T1 network connection, the least significant bit of each octet is often not used and the data is sent as seven bit symbols. This mitigates the RBS problem if the link between the two data units is completely digital, at the expense of reducing bandwidth of the link by one eighth. Since a T1 line carries twenty four 64 k channels, if one 64 k channel is used in a combined analog/digital link to a modem, conventional methods of eliminating RBS (i.e., using seven-bit symbols) would limit the maximum theoretical bandwidth of the connection to 56 k. This theoretical maximum would never be reached because of the presence of ISI and DPAs. Thus, the problem of RBS is a major obstacle to exploiting the maximum possible bandwidth of the combined analog and digital link; and if one wishes to exploit the entire bandwidth of the link, one must deal directly with the RBS problem.
The problem of RBS is even further complicated when the link between two data units includes several different digital legs such that the frequency of RBS is variable from one connection to another. In other words, if the link includes several different digital legs in which bits are robbed, the frequency of robbed bits can increase significantly.
During PCM modem training, it is impossible for the receiver to know whether a symbol has been impaired due to RBS. As a result, RBS can interfere with the equalizer training process and result in misadjustment of the equalizer. In turn, equalizer error will lead to improper and/or inadequate channel equalization, with the ensuing inability to perform other tasks such as channel measurements, etc. This will prevent the receiver from ever making proper compensations for ISI and DPAs.
Prior art FIG. 1, shows a simplified model of data transmission through a combined analog/digital link. At 11, binary data is provided in the digital part of the network and represents data from either an intrinsically binary source or an appropriately encoded (A-Law or .mu.-Law) analog quantity which is to be transmitted to the desired destination. The digital channel 13 carries binary data through one or more legs of the network. For purposes of FIG. 1, the digital channel can be characterized by the way it affects the binary data it carries relative to the original binary data presented at 11. The binary data carried by the digital channel 13 is at some point subjected to a digital-to-analog converter 15 which maps or translates binary data into an analog symbol format, such as a PCM level, suitable for transmission through an analog channel. The D/A conversion takes place at the rate of 1/T Hz, where T seconds is the duration of the symbol interval.
The analog signal is then provided to an analog channel 17 which carries the analog waveforms to a PCM modem 19. Due to its band-limited nature, the analog channel 17 introduces distortion or inter-symbol interference (ISI) as well as noise into the stream of analog waveforms it carries. ISI causes individual symbols to interact with one another, thereby distorting the signals.
The PCM modem 19 is coupled to the analog channel 17 and includes, among other things, a receiver 21 and an analog channel decoder 23. The receiver 21 receives the analog signals at its input, and includes means for synchronizing the receiver with the data source/transmitter. The receiver 21 also includes an equalizer which compensates for ISI distortion introduced in the analog channel. The equalized signal may then be translated by the analog channel decoder 23 and formatted into a binary data stream which is sent to a further destination 25 (e.g., a receiving computer).
As previously mentioned, the analog channel 17 introduces ISI which can significantly distort the signal at the receiver. Indeed, as a result of ISI, the symbol received at the receiver 21 at time instant kT is no longer determined by the transmitted symbol alone, but by a linear combination of a (theoretically possibly infinite) number of previously transmitted symbols. ISI can be a severe impairment for certain types of analog channels; especially those with spectral nulls in their magnitude response at various frequencies such as DC. The ISI problem of an analog channel is compounded by the fact that its impulse response is in general unknown. Thus, the ISI affects data symbols in an unknown way and seriously complicates the task of the receiver of correctly detecting the incoming symbols with a low probability of error. Noise added at the output of the analog channel compounds the difficulty of correcting for ISI.
Equalization of the signal to account for ISI and noise is absolutely essential for proper communications. Various equalizer filter architectures are known for such equalization. For example, an equalizer called a decision feedback equalizer (DFE) which is shown in prior art FIG. 2 is known to be effective in cases of severe amplitude distortion. As seen in FIG. 2, the DFE 30 includes a feed-forward finite impulse response (FIR) equalizer 32, first and second summers 34, 36, a decision block 38, and a feedback FIR equalizer 40. The feed-forward FIR provides a feedforward equalized component (Rff) to the summer 34 which is compared to the feedback equalized component (Rfb) provided by the feedback FIR 40 to provide an equalized estimated symbol (R). This estimated symbol (R) is provided to the decision block 38 as well as to the second summer 36. The decision block 38 generates a decision based on the equalized estimated symbol. The decision is fed back to the input of the feedback FIR equalizer 40, and is also sent to the second summer 36. The second summer 36 takes the difference between the estimated symbol and the output symbol, i.e., the error, and provides the error to the feed-forward FIR 32 and to the feedback FIR 40 in order to update the equalizer tap coefficients of the FIRs 32 and 40.
It should be appreciated that in the modem training period (prior to sending data), a decision block is not used. Rather, as seen in prior art FIG. 3, the decision block 38 is replaced with a reference generator 37 which generates a reference (known) sequence Tk. The reference sequence is compared at the second summer 36 to the estimated symbol R to provide an error e which is used as feedback in order to update the equalizer tap coefficients 31 (Cff) and 39 (Cfb) of the FIRs 32 and 40.
While the adaptive equalizer of FIGS. 2 and 3 is effective in compensating for ISI analog channel impairments, it does not account for digital channel impairments which can be present in PCM-type modem communications. In particular, the adaptive equalizers of the prior art are not effective in the presence of robbed bit signaling which causes octets in the training sequence to be translated into analog symbols which are different than what they would otherwise be. Similarly, octet transformation due to digital PAD attenuation is problematic in causing individual training symbols to be translated into different analog levels. The PAD impairment can occur with RBS, either before or after a bit is robbed.
It has been discovered that RBS, when present, occurs in a repeating frame of six bytes. Table 1, below, shows an example of an RBS Frame in which bytes 1, 3, and 4 are affected by RBS. It should be noted that, as mentioned above, RBS may be present in conjunction with DPAs and the robbed bit may occur before or after the pad.
TABLE 1 ______________________________________ ##STR1## ______________________________________

PCM modem equalizer with adaptive compensation for robbed bit signalling


An improved plunger mechanism apparatus to increase well flow production levels. Efficiency of well flow is increased by a two-piece plunger assembly apparatus that is mechanically latched during lift, separates at the well top, and allows a bottom assembly to efficiently fall to the well bottom. The top plunger piece is held at the well top for a set time or condition and when released, its open internal orifice allows it to fall to the well bottom in an efficient manner, and when at the well bottom it mechanically latches, either via a magnetic or mechanical connection, to the bottom assembly.

A plunger lift is an apparatus that is used to increase the productivity of oil and gas wells. In the early stages of a well's life, liquid loading is usually not a problem. When rates are high, the well liquids are carried out of the tubing by the high velocity gas. As a well declines, a critical velocity is reached below which the heavier liquids do not make it to the surface and start to fall back to the bottom exerting back pressure on the formation, thus loading up the well. A plunger system is a method of unloading gas in high ratio oil wells without interrupting production. In operation, the plunger travels to the bottom of the well where the loading fluid is picked up by the plunger and is brought to the surface removing all liquids in the tubing. The plunger also keeps the tubing free of paraffin, salt or scale build-up. A plunger lift system works by cycling a well open and closed. During the open time a plunger interfaces between a liquid slug and gas. The gas below the plunger will push the plunger and liquid to the surface. This removal of the liquid from the tubing bore allows an additional volume of gas to flow from a producing well. A plunger lift requires sufficient gas presence within the well to be functional in driving the system. Oil wells making no gas are thus not plunger lift candidates.
As the flow rate and pressures decline in a well, lifting efficiency declines geometrically. Before long the well begins to "load up". This is a condition whereby the gas being produced by the formation can no longer carry the liquid being produced to the surface. There are two reasons this occurs. First, as liquid comes in contact with the wall of the production string of tubing, friction occurs. The velocity of the liquid is slowed and some of the liquid adheres to the tubing wall, creating a film of liquid on the tubing wall. This liquid does not reach the surface. Secondly, as the flow velocity continues to slow the gas phase can no longer support liquid in either slug form or droplet form. This liquid, along with the liquid film on the sides of the tubing, begins to fall back to the bottom of the well. In a very aggravated situation there will be liquid in the bottom of the well with only a small amount of gas being produced at the surface. The produced gas must bubble through the liquid at the bottom of the well and then flow to the surface. Because of the low velocity very little liquid, if any, is carried to the surface by the gas. Thus, as explained previously, a plunger lift will act to remove the accumulated liquid.
A typical installation plunger lift system 100 can be seen in FIG. 1. Lubricator assembly 10 is one of the most important components of plunger system 100. Lubricator assembly 10 includes cap 1, integral top bumper spring 2, striking pad 3, and extracting rod 4. Extracting rod 4 may or may not be employed depending on the plunger type. Below lubricator 10 is plunger auto catching device 5 and plunger sensing device 6. Sensing device 6 sends a signal to surface controller 15 upon united plunger mechanism (UPM) 200 at the well top. UPM 200 is shown to represent the plunger of the present invention and will be described below in more detail. Sensing the plunger is used as a programming input to achieve the desired well production, flow times and wellhead operating pressures. Master valve 7 should be sized correctly for the tubing 9 and UPM 200. An incorrectly sized master valve will not allow UPM 200 to pass. Master valve 7 should incorporate a full bore opening equal to the tubing 9 size. An oversized valve will allow gas to bypass the plunger causing it to stall in the valve. If the plunger is to be used in a well with relatively high formation pressures, care must be taken to balance tubing 9 size with the casing 8 size. The bottom of a well is typically equipped with a seating nipple/tubing stop 12. Spring standing valve/bottom hole bumper assembly 11 is located near the tubing bottom. The bumper spring is located above the standing valve and can be manufactured as an integral part of the standing valve or as a separate component of the plunger system.
Surface control equipment usually consists of motor valve(s) 14, sensors 6, pressure recorders 16, etc., and an electronic controller 15 which opens and closes the well at the surface. Well flow 'F' proceeds downstream when surface controller 15 opens well head flow valves. Controllers operate on time, or pressure, to open or close the surface valves based on operator-determined requirements for production. Modern electronic controllers incorporate features that are user friendly, easy to program, addressing the shortcomings of mechanical controllers and early electronic controllers. Additional features include: battery life extension through solar panel recharging, computer memory program retention in the event of battery failure and built-in lightning protection. For complex operating conditions, controllers can be purchased that have multiple valve capability to fully automate the production process.
Modern plungers are designed with various sidewall geometries and can be generally described as follows:                A. Shifting ring plungers for continuous contact against the tubing to produce an effective seal with wiping action to ensure that all scale, salt or paraffin is removed from the tubing wall. Some designs have by-pass valves to permit fluid to flow through during the return trip to the bumper spring with the by-pass shutting when the plunger reaches the bottom. The by-pass feature optimizes plunger travel time in high liquid wells.        B. Pad plungers with spring-loaded interlocking pads in one or more sections. The pads expand and contract to compensate for any irregularities in the tubing thus creating a tight friction seal. Pad plungers can also have a by-pass valve as described above.        C. Brush plungers incorporate a spiral-wound, flexible nylon brush section to create a seal and allow the plunger to travel despite the presence of sand, coal fines, tubing irregularities, etc. By-pass valves may also be incorporated.        D. Solid plungers with solid sidewall rings for durability. Solid sidewall rings can be made of various materials such as steel, poly materials, Teflon, stainless steel, etc. Once again, by-pass valves can be incorporated.        E. Snake plungers, which are flexible for coiled tubing and directional holes, and can be used as well in straight standard tubing.
Recent practices toward slim-hole wells that utilize coiled tubing lend also themselves to plunger systems. Because of the small tubing diameters, a relatively small amount of liquid may cause a well to load-up or a relatively small amount of paraffin may plug the tubing.
Plungers use the volume of gas stored in the casing and the formation during the shut-in time to push the liquid load and plunger to surface when the motor valve opens the well to the sales line or to the atmosphere. To operate a plunger installation, only the pressure and gas volume in the tubing/casing annulus is usually considered as the source of energy for bringing the liquid load and plunger to surface.
The major forces acting on the cross-sectional area of the bottom of the plunger are:                The pressure of the gas in the casing pushes up on the liquid load and the plunger;        The sales line operating pressure and atmospheric pressure push down on the plunger;        The weight of the liquid and the plunger pushes down on the plunger;        Once the plunger begins moving to the surface, friction between the tubing and the liquid load acts to oppose the plunger;        In addition, friction between the gas and tubing acts to slow the expansion of the gas.
The major disadvantage of conventional plunger lifts is that the well must be shut-in in order for the plunger to fall to the bottom of the well. Two part plunger systems (ball-type or other non-positive mechanical plungers) can lose plunger piece to piece contact during lift due a drop in critical velocity, collar banging, hitting slugs of fluid, paraffin or scale particles, which decreases well efficiency. If the ball falls back to the bottom, fluid is then allowed to fall back to the bottom, which keeps the well in a loaded state. The only thing that holds the ball on the plunger is the upward flow of gas and fluid. See U.S. Pat. Nos. 6,209,637 and 6,467,544 to Wells. When the Wells two-part piston rises, changing well conditions can cause the ball to disconnect from the sleeve, resulting in lost well production.
The present invention in its various embodiments latches a lower plug to an upper sleeve, thereby preventing an accidental separation. Plunger drop travel time slows or limits well production. Also fishing balls out of a well is a problem and sometimes requires pulling the complete tubing string. Well production increases are always critical. What is needed is a plunger lift apparatus that can insure a positive contact during lift, drop back to the well bottom quickly and easily and assist in increasing well production by increasing lift cycle times. What is also needed is a two-part plunger system that is retrievable from the well. The apparatus of the present invention provides a solution to these aforementioned deficiencies.


The disclosed technology covers messaging systems and methods, and computer program products embodying such systems and methods. A computer program product may include a computer-readable storage medium with instructions executable by one or more processors to perform a method. The method may include receiving, at a message server configured to receive a plurality of messages for a plurality of computing devices, a first message intended for a first user profile. The first user profile and one or more other user profiles may exist on a single computing device. The method may also include receiving a first status update from the first computing device indicating that the first user profile is stopped or non-active, and postponing delivery of the first message to the first computing device, based on the first user profile being stopped or non-active. These and other aspects of messaging systems, methods, and computer program products are disclosed herein.

Push notification services are in widespread use for sending messages to various computing devices, including mobile devices. For example, a push notification may be sent from a message server to a user's mobile device to notify the user of receipt of a new email message. Push services can reduce the required work of a mobile device by relieving the mobile device of the need to check continuously for new email or other new messages from remote servers.
Conventionally, a single user profile runs on a mobile device. Push messages are received and processed by that user profile whenever transmitted by the message server.

Systems and methods for message delivery to mobile devices supporting multiple users


There is provided a repair method of a multi-chip that comprises a plurality of memory chips, each of the memory chips storing information with respect to remaining redundancy cells after repairing at a chip level. The repair method includes testing one of the plurality of memory chips; when the tested memory chip is judged to be defective, checking whether the tested memory chip is repairable, based on the stored information of the remaining redundancy cells; and when the tested memory chip is judged to be repairable, repairing the tested memory chip.

The present invention relates to a multi-chip and, more particularly, to a repairable multi-chip and a method repairing a multi-chip.
As recent examples of devices that have low-power functions include a smart phone, PDA, and navigation application products that utilize multi-chips, where SiP, MCP or POP technologies are applied. Such multi-chips can be formed by stacking a single control chip and two or more chips via a stack process. In this case, each of chips in a multi-chip can be a "good" chip, i.e., a chip that functions properly. But, in the case of multi-chips, there can be cells that fail with respect to timing, loading and/or resistance on an interface between chips therein after performing a stack process.
A conventional multi-chip has no repair function with respect to "badness" caused after a stack process. This can cause a large loss, considering memory cost, logic chip cost, stack process cost, testing cost, and so on.

Multi-chip and repairing method based on remaining redundancy cells


The performance of a power amplifier used in a signal transmitter, such as in a communication system (e.g., a personal communication system PCS), is optimized by coupling a controllable impedance to the output impedance of the power amplifier. The power output level of the amplifier, which is variable over a range from a minimum level to a maximum level and which is accompanied by a corresponding amplifier output impedance change, is detected, as is the operating power supplied to the amplifier. The controllable impedance that is coupled to the amplifier output is controlled as a function of the detected amplifier power output level and sensed operating power.

This invention relates to signal transmitters and, more particularly, to apparatus for optimizing the performance of a power amplifier in a signal transmitter.
Power amplifiers are used in communication systems, such as signal transmitters or transceivers, for amplifying signals to be transmitted. For example, power amplifiers are used in radio transmitters, cellular telephone transmitters, personal communication systems (PCS) and the like. In a typical signal transmission application, such as in a PCS, the signal to be transmitted, such as a speech signal, is modulated onto an RF carrier and then is transmitted from, for example, a cellular telephone to a base station. During a typical transmission session, as when speech or digital signals are transmitted by the RF carrier, the power amplifier output level varies over a range from a minimum output level to a maximum output level. As a numerical example, the output power generated from the power amplifier may vary from practically zero to an output power level on the order of about 600 milliwatts (mw).
For optimal power consumption by the power amplifier, the load impedance thereof should be matched to the power output level. Heretofore, it had been thought that it would be quite difficult and expensive to couple a variable load impedance to the power amplifier and to control that load impedance such that it is matched to the amplifier output impedance, yet varies as a function of the power amplifier output level. Hence, it has been common to fix the power amplifier load impedance at a predetermined value which, for the most part, is expected to match the power amplifier output level within an accepted tolerance range. However, when the output power generated by this amplifier is outside the range for which the load impedance has been designed, power consumption by the power amplifier may be much greater than necessary, thereby exerting a significant drain on the battery which may be used as the power source.

Apparatus for optimizing the performance of a power amplifier


A hydraulic drive unit is provided with a boom cylinder, an arm cylinder, a communication line communicating a rod chamber of the boom cylinder and a bottom chamber of the arm cylinder with each other, and a switching valve arranged on the communication line for communicating or shutting off the communication line in accordance with a rod pressure of the boom cylinder. When an arm-crowding single operation is performed and by its digging counterforce, a rod pressure of the boom cylinder rises to a high pressure of at least a predetermined pressure, the switching valve is changed over from a shut-off position to a communicating position to feed pressure oil from the rod chamber to the bottom chamber. The boom cylinder is hence caused to automatically extend, thereby avoiding lifting of a hydraulic excavator body.

As a hydraulic drive unit arranged on a construction machine to perform a combined operation of plural hydraulic cylinders, the hydraulic drive unit disclosed in JP-A-2000-337307 is known, for example. This hydraulic drive unit is arranged on a hydraulic excavator. FIG. 4 is a hydraulic circuit diagram showing an essential construction of the hydraulic drive unit disclosed in JP-A-2000-337307, and FIG. 5 is a side view of the hydraulic excavator on which the hydraulic drive unit shown in FIG. 4 is arranged.
The hydraulic excavator shown in FIG. 5 is provided with a travel base 1, a revolving upperstructure 2 arrange on the travel base 1, a boom 3 mounted pivotally in a vertical direction on the revolving upperstructure 2, an arm 4 mounted pivotally in a vertical direction on the boom 3, and a bucket 5 mounted pivotally in a vertical direction on the arm 4. The boom 3, arm 4 and bucket 5 make up a front attachment. Also provided are a boom cylinder 6 for driving the boom 3, for example, as a first hydraulic cylinder; an arm cylinder 7 for driving the arm 4, for example, as a second hydraulic cylinder; and a bucket cylinder 8 for driving the bucket 5.
FIG. 4 illustrates the hydraulic drive unit arranged on the above-mentioned hydraulic excavator and provided with directional control valves of the center bypass type for driving the boom cylinder 6 and the arm cylinder 7, respectively, in the hydraulic drive unit.
As illustrated in FIG. 4, The boom cylinder 6 is provided with a bottom chamber 6a and a rod chamber 6b. When pressure oil is fed to the bottom chamber 6a, the boom cylinder 6 is caused to extend so that boom raising is performed. When pressure oil is fed to the rod chamber 6b, the boom cylinder 6 is caused to contract so that boom lowering is performed. The arm cylinder 7 is also provided with a bottom chamber 7a and a rod chamber 7b. When pressure oil is fed to the bottom chamber 7a, arm crowding is performed. When pressure oil is fed to the rod chamber 7b, arm dumping is performed.
The hydraulic drive unit, which includes the boom cylinder 6 and arm cylinder 7 as mentioned above, is provided with an engine 20, a main hydraulic pump 21 driven by the engine 20, a boom-controlling directional control valve 23 as a first directional control valve for controlling a flow of pressure oil to be fed from the main hydraulic pump 21 to the boom cylinder 6, an arm-controlling directional control valve 24 as a second directional control valve for controlling a flow of pressure oil to be fed from the main hydraulic pump 21 to the arm cylinder 7, a boom control device 25 as a first control device for performing remote switching control of the boom-controlling directional control valve 23, an arm control device 26 as a second control device for performing remote switching control of the arm-controlling directional control valve 24, and a pilot pump 22 driven by the engine 20.
The boom-controlling directional control valve 23 is arranged on a line 28 extending to a delivery line of the main hydraulic limp 21, whereas the arm-controlling directional control valve 24 is arranged on a line 27 extending to the above-mentioned delivery line.
The boom-controlling directional control valve 23 and the bottom chamber 6a of the boom cylinder 6 are connected with each other via a main line 29a, and the boom-controlling directional control valve 23 and the rod chamber 6b of the boom cylinder 6 are connected with each other via a main line 29b. Similarly, the arm-controlling directional control valve 24 and the bottom chamber 7a of the arm cylinder 7 are connected with each other via a main line 30a, and the arm-controlling directional control valve 24 and the rod chamber 7b of the arm cylinder 7 are connected with each other via a main line 30b.
The boom control device 25 is connected to the pilot pump 22. A pilot pressure produced responsive to a manipulation of the boom control device is fed via one of pilot lines 25a,25b to its corresponding control chamber of the boom-controlling directional control valve 23, and changes over the boom-controlling directional control valve 23 to a left position or right position in FIG. 4. Similarly, the arm control device 26 is connected to the pilot pump 22. A pilot pressure produced responsive to a manipulation of the arm control device is fed via one of pilot lines 26a,26b to its corresponding control chamber of the arm-controlling directional control valve 24, and changes over the arm-controlling directional control valve 24 to a left position or right position in FIG. 4.
In the hydraulic excavator provided with the hydraulic drive unit constructed as described above, the boom control device 25 shown in FIG. 4 is manipulated upon digging or otherwise handling earth or sand. As a result, a pilot pressure is produced, for example, in the pilot line 25a so that the boom-controlling directional control valve 23 is changed over to the left position in FIG. 4. As a consequence, the pressure oil delivered from the main hydraulic pump 21 is fed to the bottom chamber 6a of the boom cylinder 6 via the line 28, boom-controlling directional control valve 23 and main line 29a, and the pressure oil in the rod chamber 6b is caused to return to a reservoir 43 via the main line 29b and boom-controlling directional control valve 23. As a result, the boom cylinder 6 extends as indicated by an arrow 13 in FIG. 5 so that the boom 3 is caused to pivot as indicated by an arrow 12 in FIG. 5 and boom raising is hence performed.
Concurrently with the above boom-raising manipulation, the arm control device 26 is manipulated and hence, a pilot pressure is produced, for example, in the pilot line 26a so that the arm-controlling directional control valve 24 is changed over to the left position in FIG. 4. As a consequence, the pressure oil delivered from the main hydraulic pump 21 is fed to the bottom chamber 7a of the arm cylinder 7 via the line 27, arm-controlling directional control valve 24 and main line 30a, and the pressure oil in the rod chamber 7b is caused to return to the reservoir 43 via the main line 30b and arm-controlling directional control valve 24. As a result, the arm cylinder 7 is caused to extend as indicated by an arrow 9 in FIG. 5 so that the arm 4 is caused to pivot as indicated by an arrow 11 in FIG. 5 and an arm-crowding operation is hence performed.
In addition to such boom-raising and arm-crowding operations as mentioned above, an unillustrated bucket control device is also manipulated to change over a bucket-controlling directional control valve such that the bucket cylinder 8 shown in FIG. 5 is caused to extend in the direction of an arrow 10 in FIG. 5. As a result, the bucket 5 is caused to pivot in the direction of the arrow 11 such that the desired digging or like work of earth or sand is performed.
FIG. 6 shows characteristic diagrams of pilot pressure characteristics and cylinder pressure characteristics in the above-mentioned combined operation. In the lower diagram in FIG. 6, times of digging work are plotted along the abscissa whereas pilot pressures produced by the control device are plotted along the ordinate. Designated at numeral 31 in the lower diagram in FIG. 6 are pilot pressures produced by the arm control device 26 shown in FIG. 4 and to be fed to the pilot line 26a, in other words, pilot pressures upon crowding the arm whereas indicated at numeral 32 in the lower diagram in FIG. 6 are pilot pressure produced by the boom control device 25 shown in FIG. 4 and to be fed to the pilot line 25a, in other words, pilot pressures upon raising the boom. Signs T1, T2 and T3 indicate time points at which boom-raising operations were performed.
In the upper diagram in FIG. 6, times of digging work are plotted along the abscissa whereas load pressures produced in hydraulic cylinders 6,7, in other words, cylinder pressures are plotted along the ordinate. Designated at numeral 33 in the upper diagram in FIG. 6 are bottom pressures produced in the bottom chamber 7a of the arm cylinder 7, in other words, arm cylinder bottom pressures whereas indicated at numeral 34 are rod pressures produced in the rod chamber 6b of the boom cylinder 6, in other words, boom cylinder rod pressures. When such a combined, boom-raising and arm-crowding operation is performed, a force in the direction of the arrow 12 in FIG. 5 is transmitted to the boom 3 by a counterforce occurred upon digging earth or sand by the bucket 5. Accordingly, the boom cylinder 6 tends to be pulled in the direction of the arrow 13 in FIG. 5, and as a consequence, a high pressure is produced in the rod chamber 6b of the boom cylinder 6 as indicated by the boom rod pressure 34 in the upper diagram in FIG. 6.
In the above-mentioned conventional technology, the digging or like work of earth or sand can be performed without an inconvenience or problem through a combined, boom-raising and arm-crowding operation. When the digging of earth or sand is performed, for example, by an arm-crowding single operation, however, an inconvenience or problem may arise as will be described next.
Specifically, when an arm-crowding single operation is performed where the ground is very hard or under such a situation that a large rock exists in the earth, the pressure in the bottom chamber 7a of the arm cylinder 7 becomes very high. As the boom 3 is pivotally connected to the revolving upperstructure 2, on the other hand, a digging counterforce by the arm 4 is applied in the direction indicated by the arrow 12 in FIG. 5 so that a tensile force is applied in the direction of the arrow 13 to the boom cylinder 6. In this state, the boom-controlling directional control valve 23 is in such a position as closing the circuit. The pressure oil in the rod chamber 6b of the boom cylinder 6, therefore, has no place to which it can drain back, so that the pressure becomes very high. In other words, despite the single arm-crowding operation, the pressure in the rod chamber 6 of the boom cylinder 6 becomes very high, so that a digging counterforce by the arm 4 may not be fully supported by the boom cylinder 6 and the body of the hydraulic excavator may be lifted as illustrated in FIG. 7. Such a situation is unpleasant for the operator, and may become a cause of a reduction in the efficiency of work.
To such a problem, a hydraulic circuit has been proposed in which as illustrated in FIG. 8, for example, a line is arranged to connect the rod chamber 6b of the boom cylinder 6 as the first hydraulic cylinder and the reservoir 43 with each other and an overload relief valve 80 is arranged on the line to release the pressure oil to the reservoir 43 when the pressure rises to at least a predetermined pressure. Such a circuit is, however, extremely disadvantageous from the standpoint of energy efficiency because a great deal of heat is produced in the hydraulic circuit upon occurrence of a situation that the overload relief valve 80 continues to release.
With the above-mentioned circumstances of the conventional technologies in view, the present invention has as an object the provision of a hydraulic drive unit which, upon performing an operation that pressure oil is fed to the bottom chamber of the second hydraulic cylinder, an excessive pressure can be released from the rod chamber of the first cylinder and the pressure oil in the rod chamber can be effectively used.

Hitachi Construction Machinery Co., Ltd.


A security system is provided. The security system comprises a plurality of hardware device modules and a plurality of sensor detection devices. At least one hardware device module has a microcontroller coupled to a memory element that stores a configuration map for remote configuration comprising configuration option information available for the hardware device module. The plurality of sensor detection devices are capable of sending a signal to one or more of the hardware device modules.

Remote configuration of a security system is known. Typically, configuration of the multiple devices in a security system is achieved by a remote programming tool that is preprogrammed with a configuration utility that has a preset option list for each device to configure that device with the security system. The remote programming tool is typically indirectly coupled to the security system via a modem connection or via an Ethernet/Internet connection. In these security systems, the programming options are limited to the preset option list hard coded onto the remote programming tool. In order for the security system to support new or modified devices, the remote programming tool must install configuration updates on a regular basis. Accordingly, it becomes difficult for the remote programming tool to configure the security system when new devices are added or existing devices are modified with enhanced functionality.
For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for improved systems and methods for remote configuration of a configurable hardware device module of a security system.

Remote configuration of a hardware device module of a security system


Disclosed is a process for the preparation of di-n-butyl terephthalate by the esterification of terephthalic acid with n-butanol in the presence of a strong acid while employing a fractionating column.

Terephthalic acid di-esters, such as Di-n-butyl terephthalate, also known as DBT, can be used as plasticizers in a variety of polymeric materials such as polyvinyl chloride. Eastman Chemical Company produces di(2-ethylhexyl) terephthalate, also known as DOTP or 168 Plasticizer, by the titanate-catalyzed transesterification of dimethyl terephthalate (DMT) with 2-ethylhexanol. A more direct route to this product has been described in parent U.S. patent application Ser. No. 11/699,652 wherein terephthalic acid (TPA) is reacted with 2-ethylhexanol using a titanate catalyst, with reaction condition involving either pressure or ambient pressure through use of a fractionating column. However, titanate catalyst cannot be used directly to produce di-n-butyl terephthalate (DBT). The present inventors have discovered that excess strong acids, such as methane sulfonic acid and sulfuric acid, in combination with a fractionating column overcome this problem.

Conversion of terephthalic acid to Di-n-butyl terephthalate


In a process for preparing C2-oxygenates by reaction of CO and H2over a rhodium-containing supported catalyst, the catalyst comprises, based on the total weight,

The invention relates to a process and a catalyst for preparing C2-oxygenates from synthesis gas, i.e. CO/H2 gas mixtures.
The heterogeneously catalyzed conversion of synthesis gas into hydrocarbons (Fischer-Tropsch synthesis) or into methanol has been known since the 1920s. It was discovered only in 1975 that rhodium catalysts can convert synthesis gas L directly into C2-oxygenates.
In principle, the direct reaction of synthesis gas over rhodium catalysts can lead to a broad range of products. Thus, methane and higher hydrocarbons and also oxygenates such as methanol, ethanol, higher alcohols, diols, acetaldehyde and acetic acid are formed over unpromoted Rh/SiO2 catalysts. Both the selectivity and the activity of rhodium catalysts can be considerably modified by doping with other elements or by appropriate selection of the support. For example, doping with lithium or potassium serves to suppress methane formation, doping with manganese gives a considerable increase in activity without the selectivity being significantly influenced, and the use of CeO2 instead of SiO2 as support results in a significant increase in the selectivity of ethanol formation. Furthermore, the product distribution depends on reaction parameters such as pressure, temperature, conversion and CO/H2 ratio.
EP-A-0 010 295 describes a process for preparing ethanol from synthesis gas, in which the reaction is carried out over a supported rhodium catalyst comprising, as cocatalyst, one or more of the elements zirconium, hafnium, lanthanum, platinum, chromium and mercury. EP-A-0 079 132 relates to a process for preparing oxygenated hydrocarbons by catalytic reaction of synthesis gas over a supported catalyst comprising, as active components, rhodium, silver, zirconium and molybdenum and also, if desired, iron, manganese, rhenium, tungsten, ruthenium, chromium, thorium and potassium. The preferred support material is silicon dioxide. J5 9078-130-A relates to a process for preparing acetic acid, acetaldehyde and ethanol by reaction of synthesis gas over a rhodium catalyst comprising manganese, zirconium and at least one alkali metal as promoters.
The direct, heterogeneously catalyzed gas-phase synthesis of acetic acid from synthesis gas over rhodium catalysts has been intensively researched, especially in the years 1980 to 1986 as part of the Japanese C1 project xe2x80x9cResearch and Development Program for New Technologies to Produce Basic Industrial Chemicals from Carbon Monoxide and other Chemicalsxe2x80x9d. During the course of this work on the synthesis of acetic acid, the influence of about 60 elements as promoters on the activity and selectivity of heterogeneous rhodium catalysts was systematically examined. It was found that promoters such as Mg, Sc, Ti, V, Cr, Mn, Mo or La increase the catalytic activity, while promoters such as Li, K, Zr or Ir lead to an increase in the selectivity of acetic acid formation. At the end of the project, an optimized Rhxe2x80x94Mnxe2x80x94Irxe2x80x94Lixe2x80x94K/SiO2 catalyst enabled an acetic acid selectivity of 71% to be achieved at a space-time yield of 344 g/l*h. A further catalyst which was not described in more detail but gave an overall selectivity to acetic acid +acetaldehyde of 90% at a space-time yield of 480 g/l*h was also developed.
The results of the Japanese Cl project have been compiled in the book xe2x80x9cProgress in Cl Chemistry in Japanxe2x80x9d, Elsevier, 1989, with specifically the work on the preparation of acetic acid from synthesis gas being described in Chapter 6 (pages 287 to 330). In the screening tests on catalyst optimization, not only was the influence of various promoters on the catalyst performance elucidated, but a number of further parameters such as the test conditions (P, T, SV, CO/H2 ratio), partial poisoning with sulfur, the support composition and pore structure, the Rh particle size and the conditions in the drying and the reduction of the catalyst were also examined. In addition, the reaction kinetics over an Rhxe2x80x94Mnxe2x80x94Irxe2x80x94Lixe2x80x94K/SiQ2 catalyst and the ageing behavior of an Rhxe2x80x94Mnxe2x80x94Irxe2x80x94Li/SiO2 catalyst were examined.
It is an object of the present invention to provide a process and a catalyst for preparing C2-oxygenates, which give the desired products with high conversions and high selectivities at a high catalyst activity and operating life.
We have found that this object is achieved by a process for preparing C2-oxygenates by reaction of CO and H2 over a rhodium-containing supported catalyst, in which the catalyst comprises, based on the total weight,
from 0.01 to 10% by weight of rhodium,
from 0.001 to 10% by weight of zirconium,
from 0.01 to 5% by weight of iridium,
from 0.01 to 10% by weight of at least one metal selected from among copper, cobalt, nickel, manganese, iron, ruthenium and molybdenum,
from 0.01 to 10% by weight of at least one alkali metal or alkaline earth metal selected from among lithium, sodium, potassium, rubidium, magnesium and calcium, on an inert support.
It has been found, according to the present invention, that the above catalyst displays a very good performance spectrum in the conversion of synthesis gas into C2-oxygenates. The catalyst displays a high activity and selectivity, even when the rhodium content is very low.
The catalyst support is preferably selected from among SiO2, Al2O3, TiO2, zeolites, activated carbon, diatomaceous earth and mixtures thereof.
The alkali or alkaline earth metal or metals is/are preferably selected from among lithium, potassium and magnesium.
The metal or metals is/are preferably selected from among copper, manganese, iron, ruthenium and molybdenum.
A preferred catalyst comprises
from 0.1 to 5% by weight, in particular from 0.5 to 3.5% by weight, of rhodium,
from 0.05 to 5% by weight, in particular form 0.08 to 4.5% by weight, of zirconium,
from 0.1 to 3.5% by weight, in particular from 0.2 to 2.5% by weight, of iridium,
from 0.1 to 5% by weight, in particular from 0.2 to 1.5% by weight, of at least one metal selected from among copper, cobalt, nickel, manganese, iron, ruthenium and molybdenum,
from 0.05 to 5% by weight, in particular from 0.1 to 1.2% by weight, of at least one alkali metal or alkaline earth metal selected from among lithium, sodium, potassium, rubidium, magnesium and calcium, on an inert support.
The catalyst of the present invention can be obtained by impregnating the inert support with catalyst metal compounds, in particular catalyst metal salts, dissolved in aqueous or organic solvents, drying and calcining the impregnated support and subsequently reducing it. The impregnation can be carried out in any desired manner, for example by steeping or spraying. Preference is given to using catalyst metal salts which are soluble in water or organic solvents such as ethanol. The order in which the support is impregnated with the catalyst metal compounds can be chosen freely. Impregnation can be carried out successively or simultaneously with all components.
According to the present invention, the catalyst is used in the reaction of synthesis gas, in particular to give C2-oxygenates such as ethanol, acetaldehyde and acetic acid.
The reaction is preferably carried out at a pressure in the range from 1 to 100 bar and at a temperature in the range from 200 to 400xc2x0 C.
The molar ratio of H2 to CO is preferably 10-0.05:1.

Process and catalyst for preparing C2-oxygenates from synthesis gas

Abstract: from 0.01 to 1O% by weight of rhodium,

Abstract: from 0.01 to 5% by weight of iridium,