A sealing device for use in a refueling opening is provided with an elastic seal member which seals a gap between a tubular casing provided in the refueling opening and a fueling nozzle inserted into the casing at the time of refueling. The elastic seal member is mounted inside a seal retaining member which is mounted inside the casing, The elastic seal member has a relief lip capable of closely contacting the casing to effect sealing, and a seal lip capable of closely containing the inserted fueling nozzle to effect sealing. A gap is formed around the outer periphery the seal lip, thereby allowing the seal lip to expand so that the inside diameter thereof increases in conformity with the outside diameter of the fueling nozzle as the nozzle is inserted.

This invention relates to a device for use in a refueling opening and, more particularly, to a sealing device for use in a refueling opening of a motor vehicle or the like at the time of refueling in order to prevent leakage of fuel and substances evaporating from the fuel.
In general, a refueling opening of a fuel tank is not provided with a sealing device for preventing substances evaporating from a fuel from escaping from the tank at the time of refueling. There is therefore a problem of evaporating substances being released to the atmosphere at the time of refueling, and there is a demand for a sealing device adapted to the fueling opening.
The inventor of the present invention has studied sealing devices for use in refueling openings and has found that a sealing device is required to satisfy the following conditions.
That is, it is desirable for the sealing device to closely contact the fueling nozzle at the time of refueling to prevent any fuel substances from being released to the atmosphere; to have a relief mechanism in order to prevent the pressure inside the fuel tank from increasing higher than a predetermined level in a case where the pressure inside the fuel tank excessively increases because the vapor of fuel substances is not released to the atmosphere; and to be capable of allowing the fueling nozzle to be inserted or drawn out with a constant load even if a portion in contact with the fuel substances and the vapor formed therefrom swells or shrinks.
The inventor had first developed a sealing device for use in a refueling opening, such as the one shown in FIGS. 6 to 9.
This sealing device for a refueling opening is constructed in such a manner that a seal retaining member 42 is disposed inside a casing 41 in the form of a tube disposed in a refueling opening (not shown), an elastic seal member 43 in the form of a ring being fixed to the seal retaining member 42. A nozzle guide member 45 for guiding a fueling nozzle 44 when the fueling nozzle 44 is inserted into the casing is also attached to the seal retaining member 42.
At the time of insertion of the fueling nozzle 44, the elastic seal member 43 effects sealing between itself and the fueling nozzle 44.
This type of sealing device for use in a refueling opening was manufactured by way of trial and was tested by experiment, and the following problems were found.
That is, influences of fuel and substances evaporating the fuel upon the swelling or shrinkage of the elastic seal member 32 appear as changes in the inside diameter D.sub.1 of the elastic seal member 43 because the outer peripheral surface of a sealing portion of the elastic seal member 43 for effecting sealing with the fueling nozzle 44 is retained over its entire area by the seal retaining member 42.
It is necessary for the elastic seal member 43 to effect sealing between itself and the fueling nozzle 44 in conformity with the outside diameter of the fueling nozzle 44 which may vary in a certain range of dispersion, and the squeeze (which is determined the inside diameter D.sub.1 of the elastic seal member 43 with which the fueling nozzle 44 is fastened see FIG. 7) is set in such a manner that the elastic seal member 43 can be brought into close contact with the fueling nozzle 44 even if the outside diameter thereof is minimum. As a result, the squeeze of fastening is excessively large when the nozzle diameter is maximum, and it further increases by the influence of swelling.
If the squeeze of fastening is increased in this manner, in other words, the elastic seal member 43 expands to a certain extent while the nozzle diameter is large, it is difficult to insert the fueling nozzle 44 into the elastic seal member 43. If, conversely, the nozzle diameter is minimum, there is a possibility of considerable deterioration of the sealing performance.


Techniques are disclosed for delivering push subscription notifications in large scale distributed systems. Subscription notifications can be delivered to mobile devices of subscribing users by monitoring, at a server, an application database comprising a data record having one or more data values, detecting, at the server, in accordance with the monitoring, a changed data value, querying a subscription database for a subscription having at least one constant value to be compared to the changed data value in accordance with a trigger condition specified in a trigger template, determining whether the trigger condition is true using the changed data value and the constant value as the values of the first and second variables, respectively, in the at least one comparison; and pushing a notification from the server in response to the trigger condition being true.

Computer programs are often designed to perform certain tasks when specific events or conditions occur. For example, when a weather forecasting service determines that rain is likely later in the day, the forecasting service can send a notification message to weather applications located on mobile computing devices via a wireless communication network. The mobile weather applications are not necessarily executing or even loaded in memory at the time the notification message is sent, so applications rely on other software modules, such as the device operating system that can receive and process incoming notifications in a timely manner. The operating system can pass the notifications to the applications associated with the notifications, e.g., to the weather application for notifications sent by the weather service. If an application is not executing when a notification is received, the operating system can bring the application into an executing state in which the application can process the notification. The operating system can then pass the notification to the application, which will act on the notification, e.g., by displaying a warning about rain being likely later in the day.
To request delivery of notifications by the operating system, applications can provide information specifying the events or conditions for which notifications are to be delivered to the application. An event or condition can be, for example, that the chance of rain later in the day is greater than 90%. The weather service then uses the event or condition to determine when to send notifications to the application. This request for notification, including the associated event or condition, is referred to as a "subscription." A subscription can be a "local" subscription, in which notifications are generated on the device and delivered to applications executing on the same device. A subscription can also be a "push" subscription, in which notifications are generated on one device, such as a server, and sent to other devices, such as mobile devices. The term "push subscription" refers to the server-initiated "pushing" of the notifications to subscribing devices. The processing performed by the service can be fairly complex. It would be desirable, therefore, to simplify the processing that applications perform to send and receive notifications.


A food product package includes a bulky food product hermetically sealed in a bag of heat shrunk film. The package has an integral self-supporting handle which is formed from plies of the film and which extends out from an end of the package in a conventional handle shape. The handle is formed by causing a skirt portion of the bag to heat shrink about a rigid member positioned to maintain the skirt portion spaced from an end of the package during shrinking.

It is customary for food processors to vacuum package bulky food articles such as whole muscle meat products, brick cheese and poultry in shrink bags. The processor loads the food article into the bag and evacuates the bag to collapse it about the food product. The bag is sealed, while in its evacuated condition, by gathering the open end and applying a metal clip or by heat sealing. The sealed bag then is passed through a hot water bath or hot air tunnel to shrink the sealed bag about the food product. Shrinking the bag in this fashion closely conforms the bag to the contour of the food product thereby making an attractive, generally wrinkle-free package.
One problem related to a shrink bag package containing a turkey or other large food items is that the resulting food package is bulky, relatively heavy, possibly frozen, and difficult to manually grasp and lift. Therefore it is desirable to provide a carrying handle to facilitate handling the food product package. For this purpose a separate handle is attached to the package at the clip closure or the package is inserted into a netting which is gathered and clipped to provide a carrying handle. Both arrangements add to the packaging costs.
Preferably, the handle should be formed integral with the shrink bag to avoid the added expense and processing steps of attaching a handle to the food product package. For poultry packaging, a handle located at the tail of the bird is preferred as this leaves the area of the package over the breast area of the bird free to receive printed information such as a decorative design, corporate logo or other identifying product information. Also, a handle at the tail of the bird provides a desirable weight distribution in that the heavier breast portion of the bird is carried below the lighter tail portion.
U.S. Pat. No. 4,555,025 discloses a shrink bag package having an integral handle. The bag package is formed of a so called "extended lip bag" wherein one bag panel extends beyond the open bag end. The handle is formed in the extended lip portion by punching a hot die through the lip to provide an opening having a fused bead extending continuously about the opening. Upon heat shrinking to form the bag package, the extended lip portion of the bag undergoes an unrestrained free-shrink so it thickens and forms a handle which protrudes longitudinally from the resulting package.
One disadvantage of the resulting package as disclosed by U.S. Pat. No. 4,555,025 is that only a single ply of heat shrunk film supports the entire weight of the bag package. Also, there is no defined, predetermined form to the handle because it is formed totally by free-shrink of the film.
Co-pending U.S. patent application Ser. No. 07/577,702 now U.S. Pat. No. 5,120,553 discloses a shrinkable bag wherein the integral handle forming portion is located adjacent a preclosed end of the bag. This arrangement allows formation of a bag package wherein a double ply of the shrunk film supports the weight of the bag package so the handle is less likely to tear under the weight of the bag package.
While a shrink bag as disclosed in U.S. patent provides an acceptable application Ser. No. 07/577,702 now U.S. Pat. No. 5,120,553 bag package having an integral handle, further improvements are desirable to enhance the bag package for retail sale. For example, in general, handles formed by heat shrinking plastic film tend not to have a distinct and well defined handle-shape appearance. Heat shrinking to form the handle as disclosed in Ser. No. 07/577,702 now U.S. Pat. No. 5,120,553 draws the handle forming portion tight against the bag package so the handle is not a prominent and recognizable feature of the bag package and may be inconvenient for grasping and lifting the bag package.
Accordingly, an object of the present invention is to provide an apparatus for making a shrink bag package having an integral handle which is formed of shrink film material and which is a prominent and well defined feature of the bag.
Another object is to provide an apparatus for making a shrink bag package having an integral self-supporting handle portion formed of shrink film material.
Yet another object of the present invention is to provide a shrink bag package having a prominent, well defined handle portion integral an end of the package and formed of shrink film material, including a self-supporting hand grip which is spaced out from the bag package and is turned so as to present a flat gripping surface and is connected to the package by a double ply of shrink film material.
A still further object of the present invention is to provide apparatus for forming a prominent, well defined handle at one end of a shrink bag package.

Apparatus for making a food containing package with integral handle


A vertical reactor system having a plurality of substantially vertically aligned reaction compartments one on top of the other, the reactant materials (and catalyst and solvent, if desired), flowable from a first top compartment through intermediate compartments, if any, to a bottom compartment from which a desired product of a reaction of the reactant materials is withdrawn, the compartments having inlets for the addition of additional reactants, catalysts, or solvents and outlets for withdrawing by-products, vapors, and water from any compartment, and processes for producing products using such a system. In one embodiment the product is a liquid epoxy resin. Stirring impellers may be provided in any compartment. A liquid seal may be provided on a shaft for the impellers and, in one embodiment the seals in each compartment may be elevated above the liquid in the compartments.

1. Field of the Invention
This invention relates to vertical continuous reactors; methods of their use; and in one aspect to methods and apparatuses for producing epoxy resins, particularly a vertical continuous epoxy resin reactor and processes using it for producing epoxy resins.
2. Background of the Invention
Epoxy resins' superior toughness, chemical resistance, heat resistance, adhesion and electrical properties have contributed to their wide use in electrical and structural applications and in protective coatings. An epoxy group (1,2-epoxide or oxirane), a three-membered cyclic ether group, characterizes the epoxy resins. A curing agent reacts with these monomers or prepolymers to produce high performance thermosetting plastics.
A common form of epoxy resins are produced by well known processes such as the reaction of dihydric phenols and epihalohydrin. In one such process the epihalohydrin and dihydric phenol react in the presence of a catalyst to produce a halohydrin-containing resin intermediate which is then reacted with a basic acting material, e.g. sodium hydroxide. Treatment of the resulting reaction mixture, such as by water-washing, removes residual catalyst and salt, producing a liquid epoxy resin.
Various dihydric phenols are employed; e.g. hydroquinone, resorcinol, catechol, and bisphenols. Suitable epihalohydrins which can be employed herein include, for example, epichlorohydrin, epibromohydrin, epiiodohydrin, methylepichlorohydrin, methylepibromohydrin, methyiepiiodohydrin, mixtures thereof and the like. Suitable catalysts include, for example, quaternary ammonium compounds, quaternary phosphonium compounds, sulfonium compounds and the like.
Suitable quaternary ammonium catalysts include, for example, tetramethyl ammonium chloride, benzyl trimethyl ammonium chloride, triethanol ammonium chloride, tetraethanol ammonium hydroxide, dodecyl dimethylbenzyl ammonium naphthenate and the like. Suitable quaternary phosphonium catalysts include, for example, those quaternary phosphonium compounds disclosed in U.S. Pat. Nos. 3,948,855, 3,477,990 and 3,341,580 and Canadian 858,648 all of which are incorporated herein by reference. Other catalysts are ethyl triphenyl phosphonium iodide, ethyl triphenyl phosphonium bicarbonate, ethyl triphenyl phosphonium acetate.acetic acid complex, benzyl triphenyl phosphonium chloride, tetrabutyl phosphonium chloride, benzyl trimethyl ammonium chloride mixtures thereof and the like. Suitable sulfonium catalysts include thiourea catalysts such as, for example, tetramethyl thiourea; N,N'-dimethyl thiourea; N,N'-diphenyl thiourea; mixtures thereof and the like as well as thiodiethanon and other sulfonium precursors.
Also suitable as catalysts are the basic ion exchange resins such as, for example, DOWEX MSA-1, DOWEX 11, DOWEX SBR, mixtures thereof and the like.
Specific processes for producing epoxy resins are described in these U.S. Pat. Nos.: 4,313,886; 2,986,551; 3,069,434; 2,840,541; 3,221,032; 4,017,523; 4,751,280; and 4,008,133; and in various foreign references, including Great Britain 2,095,679; West Germany 2,909,706 and 2,745,150; East Germany 218,767 and 213,226; and Czechoslovakia 212,856 and 210,447. Known processes for producing liquid epoxy resins from bisphenol-A and epichlorohydrin are either continuous or discontinuous processes operating in the presences of an alkali metal hydroxide in quantities of 2 moles, or about 2 moles, for every mole of bisphenol-A.
In a typical discontinuous process, a concentrated aqueous solution of alkali metal hydroxide is fed to a solution of bisphenol-A in epichlorohydrin at atmospheric or slightly lower than atmospheric pressure. The temperature is controlled to continuously distil the water introduced with the alkali metal hydroxide as an azeotropic mixture with the epichlorohydrin. After completion of the addition of the solution of alkali metal hydroxide, all the water is removed, the unreacted epichlorohydrin is recovered by distillation at pressures lower than atmospheric, and the alkali metal chloride, a sub-product of the reaction is separated by dissolving in water. Liquid epoxy resins obtained in such a process have a high viscosity, an undesirable color, and because of their relatively high chlorine content, are not suitable for various applications. Liquid epoxy resins made this way can have a residual chlorine content of the order of 0.5-0.8% by weight.
Several methods of producing liquid epoxy resins by a continuous process, by effecting the reaction of the bisphenol-A with the epichlorohydrin in a number of individual reactors installed in series are well known in the art. In such processes, the bisphenol-A and the epichlorohydrin are continuously fed to a first reactor, while the alkali metal hydroxide in aqueous solution is introduced into each reactor up to a maximum quantity equal, or about equal to 2 moles for every mole of bisphenol-A. The reaction products are discharged continuously from the last reactor and are subjected to decantation to separate the liquid epoxy resin from the water and the alkali metal chloride which is a sub-product of the reaction.
In various conventional processes, the reaction is carried out in the presence of oxygenated organic substances of alcoholic or ketonic nature. The presence of extraneous substances in these procedures can cause a decrease in the purity of the resin produced, and the reactive substances such as the alcohols or the ketones can give rise to secondary reactions with formation of various sub-products. The added substances are eventually separated from the liquid epoxy resin, and are purified before recycling them to the reaction. The liquid epoxy resin is separated from the water and the alkali metal halide which is a sub-product of the reaction.
The difficulty and the lack of spontaneity in the separation of liquid epoxy compounds from water or aqueous saline solutions, is well known. To facilitate this separation, substances capable of varying the interface tension or the density have been used in the art; but the addition of extraneous substances to the system causes a decrease in the purity of the resin and the removal of these substances often proves to be very difficult. However, when operating without these extraneous substances, lengthy periods of decantation at elevated temperature are necessary causing undesirable secondary reactions.
Other processes in which an efficient reactor system would be useful include processes for producing epihalohydrins and other chemistries requiring rapid separation of a vapor product from a liquid reaction media or a vapor by-product from a liquid reaction product.
There has long been a need for an effective and efficient continuous vertical reactor and methods of its use. There has long been a need for an effective and efficient continuous process for producing liquid epoxy resins. There has long been a need for apparatus for use in such a process. There has long been a need for a continuous process for the production of liquid epoxy resins in which reaction by-products may be removed at various stages in the process. There has long been a need for a continuous process for the production of liquid epoxy resins in which catalysts and reactants can be added in a staged manner to minimize yield losses to undesirable side reactions.


The present invention relates to a method for determining hydrocarbon production for a reservoir. The method comprises                determining a projector matrix based on a Jacobian matrix function of the gridded model, then splitting the Jacobian matrix into subsets of consecutive lines.                    For each subset of consecutive lines, creating a respective square matrix based on said subset.                        A determining eigenvectors and respective eigenvalues associated with the respective square matrix and then determining relevant eigenvectors having respective eigenvalues below a predetermined threshold.        The projector is determined as a concatenation of the extended eigenvectors ordered according to multiple criteria: the respective order value of the subset; and the respective eigenvalue of the relevant eigenvector.

The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Furthermore, all embodiments are not necessarily intended to solve all or even any of the problems brought forward in this section.
For the oil/gas company, the determination of the expected production of a reservoir is a key indicator in order to determine where to drill a well and in order to assess the economic value of a reservoir.
In the prior art, dynamic simulator is used to determine the expected production.
From a mathematical point of view, the continuity equation cannot be solved with an analytical solution (in the general case).
Therefore, to solve this problem, numerical solutions are sought, by discretizing the space (gridding) and time (time steps). To determine the numerical solutions, many methods proposed solving the following equation (combination of mass conservation equation and Darcy's Law) for each component:
            dM      k        dt    =            -                        ∑                      i                                                                          in                                                                          neighbouring                                            F          ki                      -                  ∑                  w                                                              in                                                              well                                                            Q                  k          -          w
with dMk the mass accumulated in cell k during the current time step dt for said component
with Fki the net flow rate from cell k into the neighboring cell i during dt
with Qk−w the net flow rate from cell k into well w during dt
Although this equation has a linear expression, it is, in fact, non-linear with respect to the physical unknowns (pressure, hydrocarbon component compositions, temperatures . . . ) that are needed to compute the net flow rates. Thus at each time step, one must find the unknown values in cell k so that the non-linear residual (Rfl)k is nullified:
            (              R        fl            )        k    =                    dM        k            dt        +                  ∑                  i                                                              in                                                              neighbouring                                  F        ki              +                  ∑                  w                                                              in                                                              well                                                            Q                  k          -          w
The method for the resolution (non-linear Newton iterations) is summarized in FIG. 1.
For a given time step, this time step is considered (step 101).
For the time t1 corresponding to the considered time step, the simulator chooses, a priori, a new solution X1 and starts looking at which correction Δx is needed to get the solution R(X1+Δx=0.
As it is often considered that Δx is small, it is possible to linearize the equation (step 102) into R(X1)+JX1Δx=0.
To solve the equation R (X1)=JX1Δx=0 (step 103), it is required to invert the Jacobian matrix JX1:Δx=−JX1−1R(X1)
Once Δx determined, the non-linear residual R(X1+Δx) is determined (step 104).
If the non-linear residual R(X1+Δx) is lower than a predetermined threshold ε, the time step is considered as solved and X1 is outputted (step 106).
Otherwise, step 102 is reiterated with X1=X1′ with X1′=X1+Δx if the maximum number of nonlinear iterations is not reached (test 107, a non-linear iteration being the iteration triggered by test 107: e.g. 103→104→105→107→102→103).
If the maximum number of non-linear iterations is reached, the time step may be reduced (step 108) and the non-linear iteration restarted with the reduced time step (step 101).
Due to this algorithm, it is determined that most of the computation time is spent on the step 103, i.e. inversion of the Jacobian matrix JX1.
The Jacobian JX1 is a sparse matrix: indeed, each equation of the Jacobian only involves unknowns that are connected by the mesh used for the discretization. The entries of the Jacobian matrix that are related to non-adjacent cells are 0.
In classical reservoir simulation, the solving of equation like Ax=b (where A is a Jacobian matrix, b a vector and x the solution vector to find) uses iterative methods (e.g. GMRES, generalized minimal residual method, Conjugate Gradient, BICGStab see Y. Saad, Iterative Methods for Sparse Linear Systems (2nd edition), SIAM, 2003 for details).The iterative methods classically rely on finding an approximation of the solution in a Krylov subspace such that it satisfies a Petrov-Galerkin condition (or variant of Petrov-Galerkin condition see Y. Saad, Iterative Methods for Sparse Linear Systems (2nd edition), SIAM, 2003 for more details).
The convergence of said method is function of the ratio between the greatest eigenvalue and the smallest eigenvalue of the matrix A. This ratio is called the condition number of the matrix. The larger is the condition number, the higher will be the number of iterations to solve the linear system Ax=b at a prescribed accuracy.
Instead of solving Ax=b, it is possible to solve:                M−1Ax=M−1b (left preconditioner providing the same solution)        AM−1x′=b (right preconditioner, used after a variable change)
The choice of the preconditioner M−1 is very important; it must be chosen such that the condition number of the linear operator M−1A (or AM−1) is lower than the condition number of A. The ideal choice to lower the condition number is M−1=A−1 but of course this has no interest as a preconditioner since the problem is precisely to determine A−1x. Thus a good preconditioner is a linear operator such that the condition number of the preconditioned system M−1Ax=M−1b or AM−1x′=b is much lower than the original system Ax=b and such that applying M−1 on a vector is much cheaper in number of arithmetic operations than applying directly A−1. It is noticeable that a solver can play the role of preconditioner for another solver, this has to be kept in mind to avoid any confusion since many preconditioner technique are also solver on their own (but of course when used as preconditioner the convergence tolerance is looser than when they are used as plain solver). As a direct consequence of the condition number definition, an efficient preconditioner can be constructed from the knowledge of the eigenvectors corresponding to the extremum values of the eigenvalues (for example by ensuring that M−1Av=v for v an eigenvector corresponding to a large or a small eigenvalue of A and M−1Av=Av for the other eigenvalues of A). In practice, computing eigenvectors is usually much more costly in number of arithmetic operations than solving a linear system. Nevertheless, in some problems some inexpensive approximations of the eigenvalues can be computed either by using some physical knowledge of the problem from which the Jacobian system is derived or by exploiting some properties of the matrix A and an efficient preconditioner can be devised from those approximations.
In industrial reservoir simulators, the usual numerical discretization scheme is fully implicit thus each equation of the Jacobian system involves pressure unknowns as well as fluid saturation and concentration unknowns. In a reservoir, the fluid motion is driven by the pressure field, this fact is reflected on the the fact that the conditioning of the Jacobian system is mainly dependent from the conditioning of the pressure subsystem obtained after elimination of the other types of unknowns. The CPR (Constrained Pressure Residual) preconditioning method (see J. R. Wallis, R. P. Kendall T. E. Little, Constrained Residual Acceleration of Conjugate Residual Methods. SPE 13563 presented at the 8th Symposium on Reservoir Simulation, Dallas, Feb. 10-13, 1985 and Cao, H., Tchelepi, H. A., Wallis, J., Yardumian, H.: "Parallel Scalable Unstructured CPR-Type Linear solver for Reservoir simulation", SPE 96809, Proceedings of the SPE Annual Technical Conference, Dallas, Oct. 9-12, 2005 for details) is based on this property: a Jacobian preconditioner is built as a multistep preconditioner which main operation consists in preconditioning an approximation of the reduced pressure linear system. It is noticeable that other numerical schemes such as IMPES (IMplicit Pressure Explicit Saturation) can lead directly to Jacobian system where there are only pressure unknowns in the Jacobian system. The method of preconditioning that we present in this document, is not dependent from the fully implicit numerical scheme nor the CPR method, it applies to any type of numerical scheme discretization used in a reservoir simulation as long as the preconditioner or part of the preconditioner of the Jacobian concerns a pressure unknowns subsystem which matrix is Symmetric Positive Definite (see Y. Saad, Iterative Methods for Sparse Linear Systems (2nd edition), SIAM, 2003 for mathematical definition of a SPD matrix) or close to a symmetric positive definite matrix (in the sense that
                A      -              A        t                          A      is small compared to ∥A∥ and that eigenvectors of AtA can be considered as good approximations of those of A). Due to the nature of the physical equations governing the fluid flows in porous media at any scale, the method is likely to be applied for any fluid flow simulation in a porous medium: simulation of fluid flows at the scale of a reservoir (several kilometers) or at the scale of a pore network in a rock (up to a few centimeters). As a consequence, in the rest of the document, the linear system considered for the preconditioning method described will not necessarily refer to the full Jacobian system of a reservoir simulator; it can be a system or subsystem resulting from any algebraic transformation of the Jacobian system of a reservoir simulator or system issued from any fluid flow simulator used as a pre or post stage of a reservoir simulator: the typical example being simulations at pore scale of the rocks that are used to numerically determine some rock properties needed in the reservoir simulator (those kind of simulation are usually referred to as Digital Rock Physics simulations)
The only applicability condition for the preconditioning method is that the considered system matrix is SPD or close to a SPD matrix (in the sense described above). There exists a number of methods to determine a proper preconditioner (or optimal preconditioner) on SPD matrix, e.g. Multi-Grid, Algebraic Multi-Grid (AMG), or multi levels Domain Decomposition methods (see V. Dolean, P. Jolivet and F. Nataf, An Introduction to Domain Decomposition Methods: algorithms, theory and parallel implementation SIAM bookstore, 2015 and Stüben K. Algebraic Multigrid (AMG): An Introduction with Applications. Nov. 10, 1999). A preconditioning method is qualified as purely algebraic when it only requires the matrix A of the linear system for the construction of the preconditioner (non purely algebraic method are those that require additional mathematical data such as the mesh geometry, some derivative compute from the continuous equation of the initial problem etc . . . ). The purely algebraic nature of the preconditioner is important in reservoir simulation because the system is not necessarily directly obtained by a discretization of continuous equations: for example this is the case in the fully implicit scheme when one needs to apply a preconditioner for the pressure system produced by the CPR method. Another advantage of a purely algebraic preconditioner is that it is simpler to implement and maintain in a reservoir simulator software. The usual method used to precondition the pressure subsystem in the CPR method is the Algebraic Multi-Grid (see Stüben K. Algebraic Multigrid (AMG): An Introduction with Applications. Nov. 10, 1999), thus the CPR preconditioner is usually called the CPR-AMG method.
The pressure system or subsystem preconditioner is the performance bottleneck in a reservoir simulator running on a massively parallel supercomputer (a computer that connects a very large number of CPU units). The invention presented in this document allows to build a purely algebraic preconditioning method that can replace AMG in the CPR method or be used as part of a preconditioner for a pressure linear system in a reservoir simulator.
We are considering a two-level preconditioner based on a domain decomposition of the set of unknowns. Such type of preconditioner can be written in a general additive form as:
      M          -      1        =                    ∑                  Ω          i                                            R          i          t                                  A          i                      -            1                                            R          i                      +                            Z                                (                                          Z                t                                          A                            Z                        )                                    -          1                                  Z        t
The matrices Ri correspond to a restriction operator from the global set of unknowns toward the subset of unknowns of the subdomain i (Rit corresponds to the prolongation operator). The matrix Ai corresponds to the restriction of the global matrix A to the unknowns of subdomain i (note that Ai=RiARit).
ΣΩi RitAi−1Ri can be interpreted as the local solvers in the subdomains and Z(ZtAZ)−1Zt can be interpreted as the coarse solver. Note that other variants (such as the multiplicative form) can be written as a two-level preconditioner based on a domain decomposition (see V. Dolean, P. Jolivet and F. Nataf, An Introduction to Domain Decomposition Methods: algorithms, theory and parallel implementation SIAM bookstore, 2015 for a detailed overview of those types of preconditioners).
The main ingredient in a two-level preconditioner as formulated above is the linear operator Z.
Z is classically named a projector: it is difficult to identify a proper projector Z such that the coarse problem solution contains enough information so that the condition number of the preconditioned system can be bounded independently of the number of mesh cells used in the simulation and of the physical heterogeneity (such as rock permeability heterogeneity that influences a lot the condition number of the Jacobian system). In addition, it is important that the determination of the projector Z may be parallelized easily (i.e. that a plurality of processors may compute it without important communications between processors). Finally, in order to obtain a purely algebraic preconditioner, Z needs to be constructed only from the matrix of the linear system (we will also denote this matrix by A in the following).
In the previous system used in reservoir simulation (see AMG method), the determination of the coarsening (i.e. the projector Z) implies many communications between processors in charge of said determination. It is well known that communication between processors in parallelized tasks is a real bottleneck that should be avoided.
Nevertheless, and even if the scientists are well aware of said bottlenecks for linear systems coming from reservoir simulation, no method for the purely algebraic determination of projectors is proposed in which the communication between processors are limited to the maximum or simply avoided.
Thus, there is a need to determine an adequate projector Z in an efficient algebraic way, which can be parallelized.

Method and device for determining hydrocarbon production for a reservoir


An arrangement for an EUV lithography apparatus includes a reflective optical element (60) having an optically effective surface (62) configured to reflect incident EUV radiation, and a filament arrangement (65) configured to produce a reagent that cleans the optically effective surface (62). The filament arrangement (65) has at least one filament (66) configured as a glow or heating element. The at least one filament (66) is arranged along the optically effective surface (62) of the reflective optical element (60) wherein a thickness and/or positioning of the at least one filament (66) are/is chosen so as to minimize an optical influence of the at least one filament (66) in the far field of the EUV radiation reflected by the optically effective surface (62).

An arrangement of the type mentioned in the introduction is known from U.S. 2010/0051827 A1.
A lithography apparatus generally serves for producing microstructured semiconductor components, for example. Specifically, with the lithography apparatus, projection radiation is used to image a pattern of a mask onto a wafer. During the lithographic production of semiconductor components, the resolution with which a structure can be imaged onto the substrate (wafer) is sometimes limited by the wavelength of the projection radiation. In order to obtain integrated circuits having a very high structure density and small structure dimensions, it has therefore been proposed to use projection radiation in the extreme ultraviolet spectral range (EUV). EUV radiation can have e.g. a wavelength of approximately 13 nm.
The EUV radiation source is typically a plasma source. In order to produce a plasma, often a so-called target is irradiated with laser light having a long wavelength, wherein tin (Sn), for example, is used as the target. The plasma produced then emits the EUV radiation.
In EUV lithography apparatuses, exclusively reflective optical elements are used as optical elements since there are no lens element materials which transmit radiation in the EUV range. The reflective optical elements present in an EUV lithography apparatus have to have the highest possible reflectivity in order to ensure a sufficiently high total reflectivity of the optical system of the EUV lithography apparatus. The reflectivity and the lifetime of the reflective optical elements can be reduced undesirably by contaminations of the optically effective surfaces of the reflective optical elements. In this case, the collector mirror arranged closest to the target is particularly burdened by contaminations. The collector mirror captures the EUV radiation emanating from the plasma and collects it in order to feed the EUV radiation into the further beam path. In particular, deposits of the target material, for example Sn, and of chemical compounds thereof can form at the optically effective surface of the collector mirror. However, other deposits such as carbon compounds can also deposit on the collector mirror and other reflective optical elements of the lithography apparatus.
In order to clean away contaminations of the optically effective surfaces of reflective optical elements in EUV lithography apparatuses, it is known to bring the optical surfaces into contact with activated hydrogen, i.e. hydrogen that is present for example in the form of H*, H+ and/or H2+. It is thereby possible to convert contaminations on the optically effective surfaces into readily volatile compounds that no longer adhere to the optically effective surface. A reagent within the meaning of the present invention can be activated hydrogen, for example.
It is desirable for the optically effective surfaces of the optically reflective elements to be able to be cleaned, for example with the aid of activated hydrogen, also during exposure operation of the lithography apparatus. Various approaches are known in the prior art for this purpose. The document U.S. 2010/0051827 A1 cited above describes a nested collector mirror comprising a plurality of mirror shells nested in one another, wherein the optically effective surfaces of the individual mirror shells are operated with grazing incidence. For cleaning away contaminations during operation, it is proposed, inter alia, to arrange a plurality of filaments configured as glow wires on a rear-side surface of the individual mirror shells, i.e. an optically non-effective surface facing away from the optically effective surface of the respective mirror shell, such that the glow wires are situated in the shadow region of the EUV radiation. This is intended to have no adverse effect on the optical performance of the collector mirror. However, this approach is not suitable, or is suitable only to a lesser extent, for non-nested mirrors, in particular for collector mirrors having only one optically effective surface for reflecting the EUV radiation. This is because an arrangement of the filaments on the mirror rear side would not have a sufficient cleaning effect on the optically effective surface.
Other approaches in the prior art, as described in DE 10 2008 040 720 A1, for example, provide one or more cleaning heads comprising a feed for a cleaning gas, for example molecular hydrogen, a glow wire and a discharge for atomic and/or molecular hydrogen, wherein the outlet of the cleaning device is positioned such that it is arranged outside the reflection region of the reflective optical element to be cleaned.
U.S. 2017/0064800 A1 proposes, in the case of a collector mirror configured for normal incidence of the EUV radiation, arranging a plurality of filaments in the form of glow wires outside the optically effective surface in direct proximity to the outer edge region of the optically effective surface of the collector mirror symmetrically around the center of the EUV collector mirror. In that case, the hot glow wires convert molecular hydrogen into activated hydrogen, for example into hydrogen radicals, which etch away Sn that has deposited on the optically effective surface.
Despite the numerous approaches for cleaning optically effective surfaces in EUV lithography apparatuses, there is still a need for an arrangement of the type mentioned in the introduction which is improved with regard to the cleaning effect on the optically effective surface of the reflective optical element.

Arrangement for an EUV lithography apparatus


Provided are wet etching compositions and methods for etching a surface of a microelectronic device that contains silicon nitride (SiN), silicon oxide, and polysilicon which in one embodiment is in contact with a surface comprising a compound which is electrochemically more noble than silicon, and optionally other materials which may include a conductive material, a semiconducting material, or an insulating material useful in a microelectronic device, or a processing material that is useful in preparing a microelectronic device.

In the microelectronics industry, ongoing demand exists for improved device performance and for decreased device sizes and decreased device feature sizes. Reduced feature sizes provide dual advantages of increasing device feature density and increasing device speed.
Reducing feature and device sizes requires finding new ways to improve steps of the multi-step process of manufacturing microelectronic devices. In methods for preparing many types of microelectronic devices, a step of removing silicon nitride is common. A thin layer of silicon nitride (Si3N4), typically deposited by chemical vapor deposition from silane (SiH4) and ammonia (NH3), can be useful in a microelectronic device as a barrier for water and sodium. Also, patterned silicon nitride layers are used as a mask for spatially selective silicon oxide growth. After being applied, all or a portion of these silicon nitride materials may require removal, which is commonly performed by etching.
The removal of silicon nitride from a substrate by etching is advantageously performed in a manner that does not damage or disrupt other exposed or covered features of a microelectronic device. Often, a process of removing silicon nitride is performed in a manner that preferentially removes the silicon nitride relative to other materials that are also present at a surface of a microelectronic device substrate, such as silicon dioxide. According to various commercial methods, silicon nitride is removed from a microelectronic device surface by a wet etching process that involves exposing the substrate surface to concentrated phosphoric acid (H3PO4) at an elevated temperature, e.g., in a bath having a temperature in a range from 150° C. to 180° C. Conventional wet etching techniques for selectively removing silicon nitride relative to silicon oxide have used aqueous phosphoric acid (H3PO4) solutions, typically about 85 weight percent phosphoric acid and 15 weight percent water. Using fresh hot phosphoric acid, a typical Si3N4:SiO2 selectivity can be about 40:1.
In further device structures, in addition to silicon oxide, exposed surfaces of polysilicon may also be present, which further complicates a desired selective silicon nitride etching process. Thus, there is a need for compositions and methods useful for preferentially etching silicon nitride in the presence of silicon oxide and polysilicon surfaces.

Compositions and methods for selectively etching silicon nitride films


A marine propulsion device comprising a gear housing adapted to be mounted on the transom of a boat, a clutch assembly including a clutch housing, a shaft rotatably supported within the clutch housing and adapted to be drivingly connected to a propeller, opposed bevel gears coaxially supported within the clutch housing for rotation relative to the shaft, and a clutch mechanism located between the bevel gears for causing selective and alternative driving engagement of the bevel gears and the shaft, and a mechanism for affording insertion of the clutch assembly as a unit into the gear housing and for affording removal of the clutch assembly as a unit from the gear housing.

The invention relates to marine propulsion devices, and, more particularly, to stern drive units.
Still more particularly, the invention relates to clutch assemblies for stern drive units. Still more particularly, the invention relates to cone clutch assemblies for stern drive units.
Known cone clutch assemblies are relatively difficult to insert into and remove from marine propulsion gearcases and are therefore relatively difficult to service.
Attention is directed to the following U.S. Pat. Nos.:
______________________________________ 3,212,349 Oct. 19, 1965 3,269,497 Aug. 30, 1966 3,376,842 Apr. 9, 1968 3,396,692 Aug. 13, 1968 3,915,270 Oct. 28, 1975 4,016,825 Apr. 12, 1977 4,191,063 Mar. 4, 1980 4,244,454 Jan. 13, 1981 4,257,506 Mar. 24, 1981 4,397,198 Aug. 9, 1983 4,474,072 Oct. 2, 1984 4,630,719 Dec. 23, 1986 4,634,391 Jan. 6, 1987 4,679,682 Jul. 14, 1987 4,764,135 Aug. 16, 1988 ______________________________________

Marine propulsion device with removable clutch assembly


ACDMAmobile communication system is disclosed in which a desired soft handoff operation is carried out by inhibiting signaling message transmission when a radio receiving condition at a receiving station is deteriorated. The system includes a plurality of mobile stations; a plurality of base stations, each including a transmitter for transmitting a common traffic channel to which each of the plurality of mobile stations can refer; and higher rank equipment for controlling and managing the plurality of base stations, including a table for managing the busy-idle state of each traffic channel in said plurality of base stations and a transmitter for transmitting information in said table to the plurality of mobile stations through the common traffic channel, wherein each of the plurality of mobile stations reports to said base station currently communicating at the time of soft handoff, information having, the received power of a pilot channel from the base station currently communicating, as well as the received power of a pilot channel from a target base station of soft handoff, and a short code of an idle traffic channel randomly selected using busy-idle information on traffic channels of said target base station obtained from the table information received through said common traffic channel of the target base station.

The present invention relates to a Code Division Multiple Access (CDMA) mobile communication system having a feature in transmitting a signaling message and more particularly a CDMA mobile communication system having a feature in transmitting a signaling message which is advantageous to the reception of an Extended Handoff Direction Message on executing a soft handoff operation.
In a CDMA mobile communication system, an identical frequency zone is shared by a plurality of communication users. This may cause deteriorated communication quality because signals sent from other communicators may act as interference signals to the communication.
Particularly, when communications are simultaneously carried out using a mobile station located in the vicinity of a base station and another mobile station located remotely to a base station, signals from a near mobile station are received by the base station at high electric power level, while signals from a far mobile station are received at low power level. This produces substantially deteriorated communication quality to the remotely located mobile station, which is caused by the signal interference by the near mobile station. This problem is known as a xe2x80x9cnear-far problemxe2x80x9d.
In order to cope with above-mentioned problem, there has been studied to introduce a technique for controlling transmission power. The transmission power control method controls transmission power to maintain Eb/No at a constant level irrespective of the location of a mobile station. Here, Eb/No denotes a ratio of received energy (Eb) to received noise energy (No) respectively measured at a receiving station.
To realize the method, a power control bit has been introduced to insert in transmission frames to perform a xe2x80x9cclosed loop adjustment controlxe2x80x9d, by which, at a receiving station, transmission power is adjusted based on the received power control bit.
Specifically, an average frame error rate (FER) is measured at a base station to compare with a target FER. When a difference exists between the target FER and a measured average FER, a target Eb/No is updated so that an average FER reaches nearer to the target FER.
At the base station, Eb/No is measured to compare with a target Eb/No. If a measured Eb/No is greater than the target Eb/No, a power control bit is inserted in information signals of forward (downlink) frames to direct the mobile station to lessen the transmission power therefrom. On the other hand, if a measured Eb/No is smaller than the target Eb/No, a power control bit is inserted to direct the mobile station to increase the transmission power.
At the mobile station, the power control bit is extracted from information signals in received frames. Transmission power is adjusted according to the power control bit.
Similarly, at the mobile station, an average FER (frame error rate) is measured to compare with a target FER. When a difference exists between the target FER and the measured average FER, a target Eb/No is updated so that a measured average FER reaches nearer to the target FER. Also, Eb/No is measured in transmission signals from the base station to compare with a target Eb/No. If a measured Eb/No is greater than the target Eb/No, a power control bit is inserted in information signals of reverse (uplink) frames to direct the base station to lessen the transmission power output therefrom. On the other hand, if a measured Eb/No is smaller than the target Eb/No, a power control bit is inserted to direct the base station to increase the transmission power.
At the base station, the power control bit is extracted from information signals in received frames. Transmission power is adjusted according to the power control bit.
Accordingly, a closed loop adjustment control is carried out to control transmission power in cooperation with the mobile station and the base station.
On the other hand, call control sequences (call originating, terminating, handoff, and so forth) in a CDMA system are carried out independently to the transmission power control mentioned above. In the conventional technology, signaling messages are transmitted in call control sequences without any consideration on the condition of received radio wave.
Therefore, there are cases that signaling messages are transmitted even when a radio condition is deteriorated at the receiving side. In such cases, the transmitted signaling messages may not be received because of an occurrence of frame error.
To avoid risks of reception failure in conventional CDMA mobile communication system, such a measure has been introduced as a retransmission of a signaling message when an acknowledgement message cannot be received within a predetermined period after the relevant signaling message is transmitted.
However, the above-mentioned measure may cause another problem that the retransmitted signaling message newly becomes an interruption source against communications of other mobile stations.
It is accordingly an object of the present invention to provide a mobile communication system using CDMA (Code Division Multiple Access) scheme having a feature in signaling message transmission control which ensures a predetermined processing by avoiding the transmission of a signaling message when the radio receiving condition at the receiving side is deteriorated.
It is another object of the present invention to provide a mobile communication system which controls the transmission of a signaling message at the start of soft handoff procedure by which communication is carried out particularly among a plurality of base stations.
In order to achieve the aforementioned object, the transmission timing of a signaling message in the present invention is controlled considering the radio receiving condition at the reception side.
Preferably, in the present invention, a mobile communication system based on CDMA scheme comprises a plurality of mobile stations, a plurality of base stations, and higher rank equipment (i.e. a mobile switching center and a base station controller) for controlling and managing the plurality of base stations. In the base stations, a means is provided for transmitting a common traffic channel to which each plurality of mobile stations can refer.
In each of the higher rank equipment mentioned above, a table is provided for managing the busy-idle state of each traffic channel in each plurality of base stations. A means is also provided for transmitting information in the above-mentioned table to the plurality of mobile stations through the common traffic channel of the base station.
It is a feature of the present invention to provide the mobile stations with a means for reporting, during soft handoff process to communicate simultaneously with the plurality of base stations, to the base station currently communicating the received power of a pilot channel from the base station currently in communication, as well as the received power of a pilot channel from a target base station of soft handoff, and a short code of an idle traffic channel randomly selected with a random number or the like using busy-idle information on traffic channels of the target base station of soft handoff based on the table information received on the common traffic channel of the target base station.
Further, preferably, the above-mentioned common traffic channel is transmitted using a common short code and a common long code.
Still further, the above-mentioned higher rank equipment provides a table for managing the busy-idle state on traffic channels of base stations surrounding a base station currently communicating with a mobile station, the content of the table being transmitted from the base station to the mobile station through a traffic channel each time the table is updated.
At the time of soft handoff when simultaneously communicating with a plurality of base stations, the mobile station obtains report information on the received power of a pilot channel from the base station currently communicating, as well as the received power of a pilot channel from a target base station of soft handoff, and a short code of an idle traffic channel randomly selected using a random number or the like from idle traffic channels of said target base station extracted from traffic channel busy-idle information related to said surrounding base stations received from said higher rank equipment.
Still further, preferably, in the above-mentioned procedure the higher rank equipment provides a means for receiving the report information from the mobile station through the base station to examine using the table whether the short code specified in said received report information is idle. When the short code is determined to be idle, the higher rank equipment directs the target base station of soft handoff to acquire a reverse traffic channel of the mobile station to start to transmit a traffic data of the mobile station through the traffic channel specified by the short code. A means is also provided in the higher rank equipment that, with setting busy, state on the short code in the table, and transmitting the table information to the mobile station through the traffic channel of the base station currently communicating and through the common traffic channel of the target base station of soft handoff.
Still further, preferably in a mobile communication system adopting CDMA scheme which includes a plurality of mobile stations, a plurality of base stations and higher rank equipment for controlling and managing the base stations, a power control bit is transmitted and received between the mobile station and the base station, to control to inhibit the transmission of signaling messages to the mate stations when the power control bit indicates deteriorated receiving condition.
Also, preferably the aforementioned signaling message is an Extended Handoff Direction Message transmitted through a forward traffic channel from a target base station of soft handoff to a mobile station at the start of soft handoff operation.
Still further, preferably in a CDMA mobile communication system which includes a mobile station, a first base station and a second base station each having mutually neighboring coverage areas, and higher rank equipment for managing the first base station and the second base station, the higher rank equipment in the system provides a table for managing the busy-idle state of codes allocated to a forward traffic channel of the second base station, and at least either the first or the second base station provides a code information transmission means for transmitting to the mobile station the busy-idle information obtained from the higher rank equipment. The mobile station in the system provides; an information reception means for receiving the busy-idle code information; a selection means to select an idle code by use of information content received by the information reception means; a report means to report a signal to the higher rank equipment to specify the selected code through the base station at the time of handoff from the first base station to the second base station; and a reception means for performing a receiving operation on a traffic channel from the second base station to the mobile station itself by use of the selected code. In addition, the higher rank equipment provides a control means for controlling the second base station to start to transmit a traffic channel to the mobile station by use of the specified code when the report is received.


A disk drive unit includes a disk stabilizer block supporting a reading and/or writing head. The disk stabilizer block is formed a surface to sealingly contact with a mating surface of the disk. At least one void is formed on the disk stabilizer block for defining a chamber around the reading and/or writing head, in which Bernoulli drawing force is generated for drawing a flexible storage medium disk. The void reduces contact area between the stabilizer block and the disk for avoiding influence of tolerance in production of the stabilizer block and influence of waving of the disk during rotation.

1. Field of the Invention
The present invention relates generally to a disk drive unit for transferring information between a disk and a reading and/or writing head for recording and/or reproducing information. More specifically, the invention relates to a disk drive unit which is suitable for recording and/or reproducing information on a flexible disk. More particularly, the invention relates to a disk drive unit which can establish a stable of relationship between the flexible disk and the reading and/or writing head during recording and/or reproducing information on the disk.
2. Description of the Background Art
U.S. Pat. No. 4,600,955, issued on July 15, 1986 to Curtis R. Regruit and U.S. Pat. No. 4,620,250, issued on Oct. 28, 1986 to Robert G. Hill disclose so-called "contacting" type information transfer technology for recording and/or reproducing information on a flexible magnetic disk. Both of these U.S. patents propose employment of a head-to-disk stablizing unit for stably establishing head-to-disk contact. In the proposed technology, a flexible disk is rotatably housed within a disk cartridge in such a manner that the successive radial portions of the disk move over an opening formed through the disk cartridge. The opening of the disk cartridge is disposed to provide limited radial access to the disk. The head-to-disk stabilizing unit seals the opening to cause formation of a Bernoulli drawing force for forming the successive radial positions of the disk as each portion is passed over the opening. Such drawing force momentarily deflects each portion of the rotating disk toward the opening, causing a deflected portion of the disk to remain substantially in contact with a magnetic recording or reproducing head movable along the opening and thus ensuring stability of the head-to-disk contact.
In order to exert the drawing force, vacuum pressure is generated around the head. The disk is forced toward the head for establishing firm contact with the later so as to enable a steady transfer of information between the head and the disk. Such arrangement for establishing head-to-disk contact is successful to assure head-to-disk contact. However, the magnitude of vacuum pressure to be generated around the head fluctuates. Namely, fluctuation of the vacuum pressure is caused by tolerance in the surface flatness of a stabilizer block which determines the sealing ability. The sealing ability may be influenced not only by surface flatness of the stabilized block but also by waving of the flexible disk during rotation. Due to such fluctuation of magnitude of vacuum generated around the magnetic head, contacting force between the head and the disk can fluctuate to cause variation in information transfer performance.

Disk drive with stabilizer block for insuring stable contact between a read/write head and a flexible recording medium


A backrest assembly for a wheelchair includes a support plate pivotally connected to a seat, wherein the support plate is configured to be pivotally adjusted between upright and reclined positions with respect to the seat; a slide plate slidably secured on a front surface of the support plate; and a backrest adjustment assembly operatively connected to the support plate and the slide plate. The backrest adjustment assembly includes a link configured to adjust the support plate. The slide plate slides over the support plate through the link.

Power wheelchairs are used by disabled individuals in order to move around in comfort and relative ease. Indeed, these wheelchairs have improved throughout the years to provide numerous features that provide additional comfort to individuals.
A power wheelchair typically includes a base having wheels. The base supports a seat assembly. The seat assembly typically includes a seating area and a backrest. The individual controls operation of the wheelchair through a control interface, such as a joystick, typically positioned on an armrest of the seat assembly. The control interface is in electrical communication with a processing system that is also connected to motors that drive the wheels, a steering mechanism, and the like. The processing system generally controls overall operation of all powered aspects of the wheelchair.
An individual may adjust the backrest for comfort. For example, the backrest may be pivoted back to provide a reclined back support.
FIG. 1 illustrates an isometric side view of a conventional wheelchair 10. The wheelchair 10 includes a backrest 12. The backrest 12 is adjusted through a backrest adjustment assembly 14 positioned behind the backrest 12. The backrest adjustment assembly 14 is operable to pivot the backrest 12 by pivoting the backrest 12 about two pivot hinges 16 on either side of the backrest 12 proximate the seat 18.
Additionally, with respect to many wheelchairs, the backrest adjustment assembly may be bulky and obtrusive. Further, pivot hinges on the sides of certain backrests may contact an individual within a seat when the backrests are reclined. As such, an individual may experience discomfort while seated. Further, the individual may find that the pivot hinges may impede the individual while trying to unseat his/herself. That is, when the backrest is reclined, the pivot hinges may come into contact with an individual's elbows.
Additionally, certain types of pivot hinges tend to bind up at times due to the location of the pivot hinges at a lower portion of backrest near the seat. Thus, adjustment of the backrest may be uneven and halting.


A valve assembly comprises: a valve body including a passageway through which a first gas can be transmitted through the valve assembly; a valve flow control element movable relative to the valve body between an opened position wherein flow through the passageway is at a maximum flow, and a closed position wherein flow through the passageway is at a minimum flow, the valve flow control element is shaped so that a control gap is provided between the valve body and valve flow control element through which the first gas can flow, and the dimensions of the control gap vary depending on the position of the valve flow control element relative to the valve body; and a gas injector arrangement for selectively injecting a second gas into the control gap when the valve assembly is used to control the flow of the first gas through the passageway. The injection of the second gas when the valve flow control element is at or near its closed position helps minimize condensate being deposited on the valve flow control element, as well as reduce the closed conductance of the valve.

When used, the term "gas" shall refer to both "gas" and "vapor" in the event the terms are considered to be different.
Control valves are well-known in the art as a means for regulating the rate of flow of a gas through a conduit. One type of control valve is a "flapper" valve (also sometimes referred to as a "throttle" or "butterfly" valve) in which a "flapper" or plate-like valve flow control element is disposed inside a fluid passageway and centrally or close to centrally mounted on a rotatable shaft passing laterally through the interior of the passageway. The orientation of the plane of the flapper is typically adjustable by rotating the shaft in a clockwise and/or counterclockwise direction. The flapper is precisely dimensioned so as to close and more or less seal the passageway to stop or at least substantially reduce fluid flow to a minimum flow when the plane of the flapper is oriented to block the flow of gas, at a 0° position. Alternatively, rotating the shaft and the flapper between 0° and 90° or so, such that the plane of the flapper moves from a fully closed position to a fully opened position, results in the ability to control the flow rate of gas through the passageway by controlling the position of the flapper between some minimum or zero flow to a maximum flow. The simplicity and ease of operation of such flapper valves makes them particularly well suited to regulating the flow of gases in a control system that requires delivery of gases in precise amounts.
Another type of valve useful in regulating gas flow is the pendulum or gate valve. A pendulum or gate valve assembly generally includes a housing containing a pendulum or gate valve flow control element, an interior space and a pair of openings through which gas can enter and exit the interior space.
As its name implies, the valve flow control element (usually referred to as a "gate") is moveable between fully opened and fully closed positions. The valve flow control element, usually in the form of a disk, is connected to a rotatable shaft by a pivot arm. In a completely opened position the disk of the pendulum valve is typically positioned outside of the flow path defined by the openings so that fluid can enter and exit the interior space of the housing. In a completely closed position the disk is moved into sealing contact with a valve seat surrounding one of the openings so that fluid can not pass through the valve.
The movement of the gate usually requires rotational (i.e., pivotal or lateral) movement between the completely opened position and an intermediate position, and then at least some longitudinal (i.e., translational, linear or axial) movement from the intermediate position to the completely closed position where the gate disk is in sealing contact with the valve seat. In order to obtain this combination of rotational and translational movement, pendulum valves typically use some type of rotation-axial translational mechanism to move the valve body in the desired directions as it moves through its entire range of motion.
Both types of valves, throttle and pendulum valves, can be used to control the rate of flow of gases delivered to processed-controlled systems, such as a CVD (chemical vapor deposition) system. The gases that are used in processes performed by processed-controlled systems are many and varied. A number of important industrial chemicals used in such processes exist in the liquid phase at or about normal room temperature and pressure, but transition to the vapor phase under normal atmospheric pressure at elevated temperatures. For many industrial applications, it is preferred to handle these chemicals in the vapor phase while, at the same time, minimizing excessive, unnecessary inputs of thermal energy. Striking this balance, however, presents special problems in the case of throttle and pendulum valves for regulating the flow of these vapor-phase chemicals. Unless all wetted surfaces of the valve are maintained at temperatures above the liquid-vapor transition temperature of the chemical being regulated, there is a danger of condensation on a valve interior surface resulting in possible corrosion of the valve, contamination of the fluid stream, and pooling of liquid adversely affecting valve operation. As shown in FIGS. 1 and 2, gas flow around the valve flow control element of a flapper valve can condense not only on the valve flow control element as shown at 18, but also on the internal passageway wall of the valve body as shown at 20.
As a result the surfaces of valve flow control element and the valve body can become contaminated with condensate, interfering with the operation of the valve, and shortening its life when the valve needs servicing and/or replacement. Valves are often heated, externally, around the body of the valve. A valve designed so that the valve shaft can be directly heated in an effort to keep the flapper warm is also available. Similarly, over rotation of the flapper in order to wipe the flapper body clean of contaminates is also known.
In the case of the flapper valve, installing a heater in the valve for heating the flapper above the temperature required to keep the process gas flowing through the valve in its gas phase does not always solve the problem. It is expensive, requires power and at times can not completely protect the flapper due to cooling of the flapper by gas flow. There are also cases where the contamination occurs downstream of the leading edge of the flapper due to the fluid dynamics of the gas flow (large pressure drops and potential cooling). An over-rotation method does not necessarily protect all the critical flapper surfaces from contamination.
In the case of both types of valves, it is important to design the valves so that the closed conductance of the valve is at a minimum so as to minimize leakage through the valve. As will be more evident hereinafter, a control gap between the valve flow control element and the valve body results in a relatively large conductance when the valve body is in the fully closed position. Common methods of reducing closed conductance are: creating a small gap (or extending the length of the gap) by a number of mechanical methods including use of soft sealing materials to close the gap. However, creating small gaps by whatever means usually results in more expensive components and mechanisms, with the small gap being susceptible to contamination. If the control gap is filled with a seal of some sort, then wear (which requires periodic replacement), particle generation and poor motion control (due to friction and hysteresis) often result. It is desirable to control and reduce the closed conductance of a control valve without the use of mechanical parts to do so. Further, it is desirable to reduce contamination of a valve flow control element thereby extending the life of the valve before servicing is required.


When spatial multiplexing is performed to any of a plurality of receiving antennas included in each terminal, it becomes possible to obtain excellent receiving characteristics by combining signals received by all antennas appropriately. A receiving antenna unit 28 receives channel state information from each terminal, a channel matrix H is obtained. A transmit weight/interference coefficient calculation unit 24 calculates a transmit weight and an interference coefficient based on channel matrix. The transmit weight is input to transmit weight multiplication units 17 and 23. The interference generation unit 15 generates an interference signal based on the interference coefficient. An interference subtraction unit 13 subtracts the interference signal from a desired signal. A modulo unit 14 adds a signal so that amplitude of an information signal output from the interference subtraction unit 13 falls within a constant range. A signal multiplexing unit 18 performs spatial multiplexing to the signal performed nonlinear arithmetic.

In order to resolve densely used frequency resources along with an increased data communication volume in the cellular system, as a technology to realize a high frequency usage efficiency and high-speed transmission, downlink MIMO (Multiple-Input Multiple-Output) transmission in which a plurality of transmitting signals are subjected to spatial multiplexing using a plurality of transmitting antennas included in a base station has been actively researched. In the downlink MIMO transmission, Single User-MIMO (SU-MIMO) in which a plurality of transmitting signals are subjected to spatial multiplexing which are addressed to a single terminal having a plurality of antennas is an essential technology to improve maximum transmission speed of each terminal, in which, however, there is a possibility that a transmitting antenna included in a base station is not effectively used due to limitation of the number of antennas included in the terminal. Contrary to this, as shown in FIG. 7, Multi User-MIMO (MU-MIMO) in which transmitting signals addressed to a plurality of terminals 2000a, b and c are subjected to spatial multiplexing to be transmitted simultaneously enables to effectively use an antenna on a base station side even when only a small number of antennas are included in the respective terminals 2000-a, b and c, thus attracting attention as a technology to improve cell throughput.
In the MU-MIMO transmission, for transmission of signals addressed to a plurality of terminals with a same resource, it is necessary to apply precoding to signals on a base station side in advance for transmission so that those received by respective terminals do not interfere with each other. A method of the precoding is roughly classified into linear precoding in which a plurality of transmitting signals are multiplied by a linear weight, and nonlinear precoding in which a known interference signal is sequentially subtracted from a transmitting signal and thereafter multiplied by a linear weight, in which the linear precoding is, though characteristics thereof are slightly degraded compared with the nonlinear precoding, able to realize spatial multiplexing to a plurality of signals with very simple processing.
The linear precoding includes some types, in which linear MMSE (Minimum Mean Square Error) precoding which minimizes a mean square error between a signal received at each terminal and a desired signal is a method in which excellent transmitting characteristics are obtained with relatively simple processing. Here, a weight PMMSE according to linear MMSE is shown as follows in a case where a base station having four transmitting antennas performs spatial multiplexing to signals for four terminals each having two receiving antennas. Note that, each terminal is assumed to notify a base station of channel states between one of the two receiving antennas included in each terminal and the four antennas included in the base station. When a matrix which collectively represents channels notified from each of the terminals respectively is assumed to be H, the weight PMMSE is expressed as follows.[Math 1]PMMSE=(HHH+ξI4×4)−1HH  (1)
Wherein, H=[H11T H21T H31T H41T]T, and Hmn is a vector with one row and four columns representing channels between an antenna n of a terminal m and four antennas in a base station. Further, ξ is a mean noise power to signal power ratio, and Ik×k shows a unit matrix of k rows and k columns. Here, when a signal vector addressed to terminals is assumed to x=[x1 x2 x3 x4]T, a receiving signal vector of collected signals received by respective antennas for notification of a channel to the base station, y=[y11 y21 y31 y41]T is represented by y=HPMMSE x+n. Wherein n=[n11 n21 n31 n41]T is a vector representing thermal noise added at the antenna n of the terminal m.
Multiplying a signal addressed to each terminal by such a linear weight PMMSE for transmission enables to perform spatial multiplexing to signals addressed to a plurality of terminals while suppressing multi-user interference in which signals addressed to respective terminals interfere with each other on a receiving side. In this manner, the terminal m for receiving signals after being subjected to spatial multiplexing in this manner demodulates signals received by an antenna 1 respectively to be able to obtain desired information, however, each terminal has two receiving antennas respectively and even at an antenna 2 which is not a target of spatial multiplexing processing in the base station, some signal is to be received. The signal received by the antenna 2 is not the target of spatial multiplexing processing in the base station, and thus includes a considerably large amount of multi-user interference, so that even when the signal received by the antenna 2 of each terminal is demodulated, it is impossible to obtain a desired signal correctly. However, it has been known that since this signal also includes a desired signal component, appropriately combined with the signal received by the antenna 1 and the combined signal is demodulated, excellent receiving characteristics are thereby able to be obtained compared to a case where a signal received only by the antenna 1 is demodulated (Non-Patent Literature 1).
Here, a receiving signal vector ym=[ym1 ym2]T received by two antennas of the terminal m is expressed by ym=HmPMMSE x+nm. Wherein Hm=[Hm1T Hm2T]T, and nm=[nm1 nm2]T is a thermal noise vector at the terminal m. In a combining method shown in Non-Patent Literature 1, such the received signal is multiplied by a receiving MMSE weight expressed by the following formula and subjected to combining. The receiving weight is to minimize a mean square error between a signal received at each terminal and a transmitting signal.[Math 2]Wm=(HmmPMMSE)H{HmPMMSE(HmPMMSE)H+ξI2×2}−1  (2)
The signal after multiplication of a receiving weight at the terminal m is expressed as Wmym=Wm (HmPMMSE×+nm), and an m-th signal among the signals after multiplication of the receiving weight is a desired signal of the terminal m. At each terminal, signals received by two antennas are combined in this way, so that it becomes possible to combine a desired signal component included in a signal received by an antenna which is not subjected to spatial multiplexing on a base station side, thereby allowing to obtain excellent receiving characteristics compared to the case of demodulating a signal received by one antenna.
Additionally, in general, there is a difference between the time of measuring a channel H at a terminal and the time of spatial multiplexing transmission using a linear weight based on the measured channel H, and thus, in the case of movement of a terminal, or the like, the channel varies temporally so that the multi-user interference is not completely suppressed, which poses a problem, however, since the combining method shown in Non-Patent Literature 1 is a method of combining signals received by two antennas based on an actual channel state in spatial multiplexing transmission, which is considered to be effective for suppressing multi-user interference occurred due to such time variation of a channel.

Receiving apparatus, transmitting apparatus and wireless communication system using them


A method of printing a receiving material wherein said receiving material is fed through a printer including a first and a second image-forming unit for substantially simultaneous printing of the front and back of said material in a transfer nip, whereby the two images are brought into register in the lateral direction with the receiving material by determining, prior to the formation of the images, a reference position at the transfer nip; forming the first image in such manner that part of said image which corresponds to the said reference position in the transfer nip substantially coincides therewith; and also forming the second image in such a manner that part of said image which corresponds to the said reference position in the transfer nip substantially coincides therewith; and feeding the receiving material to the transfer nip in such manner that that part of said material which corresponds to the reference position coincides substantially therewith at the transfer nip.

The present invention relates to a method of printing a receiving material including the steps of feeding the receiving material through a printer containing a first and a second image-forming unit, each of the units containing a write head and an image medium. The method includes forming, by means of the first image-forming unit, a first image on the first image medium using the first write head; forming, by means of the second image-forming unit, a second image on the second image medium using the second write head, transferring, in a transfer nip, the first image to the front of the receiving material and the second image to the back of said material. The present invention also relates to a printer suitable for using the present including a method of adjusting the printer.
A method of this kind is known from U.S. Pat. No. 5,970,295. In this method, each of the image-forming units includes a write head for writing an electrostatic latent image on a photoconductive image medium and means for developing said image to form a visible image, using toner. The developed image is then transferred to an intermediate element in the form of an endless rubberized belt. The two intermediate elements of the image-forming units come together at the transfer nip. By feeding a sheet of receiving material through this transfer nip the front and back of the material can be printed substantially simultaneously. This gives the advantage that a sheet does not have to be turned over when it is required to be printed on both sides. As a result, the feeding of the receiving material is simplified and registration errors can be avoided or at least reduced. Minor register errors, however, can occur because the two image-forming units need not be identical. As a result, despite the fact that both images are written at the same time with the write heads, it may happen that one image reaches the transfer nip earlier than the other. A difference in head level, i.e. the position of an imaginary frame around a printed image with respect to the edge of the receiving material situated furthest downstream (also known as the leading edge), between the front and back of the receiving material is the result. A solution to this problem is known from the patent specification. How much time elapses between writing a latent image on the image medium and transferring the image formed therewith to the receiving material is determined by means of reference images for each of the image-forming units. If there is a difference in this time between the first and second image-forming units, then the time at which at least one of the printheads writes is adapted so that this difference is cancelled out. Another possibility is to adapt the speed at which the image media or intermediate elements revolve. Here again the difference in the time can be eliminated.
A disadvantage of the known method is that only registration deviations in the direction of transit of the receiving material can be remedied therewith. Adjustment of the writing time or a change of the speeds of revolution of the image-carrying media only gives possibilities for adjusting the position of an image on the receiving material in the direction of transit of the material. Although the registration errors that can be expected are probably more pronounced in this direction, the increasing demands made by users with respect to register quality means that even minor registration errors in a direction extending transversely to the direction of transit of the receiving material are found to be extremely disturbing.
For printers which use only one image-forming unit various solutions are known from the prior art to prevent registration errors in the lateral direction.
One solution proposes determining where the image is situated in the transfer nip, the sheet of receiving material being fed to the transfer nip in such a manner that it exactly coincides with the image. In this method, abbreviated as "image-sends-sheet," the sheet of receiving material is thus, in each case, sent to the corresponding image depending on where the image is situated in the transfer nip. In a printer with two image-forming units, use of this method results in good register of only one of the two images. A choice must then be made as to which of the two images is used to send the sheet. The position of the other image on the sheet of receiving material is then an uncertain outcome.
Another solution proposes measuring where the sheet of material is situated and so writing the image in dependence on the measurement in the lateral direction that the image coincides with the receiving material in the transfer nip ("sheet-sends-image"). This solution can in principle be successfully used in a printer with two image-forming units. However, since the instant of writing takes place long before the sheet of receiving material really is present in the transfer nip (the image must of course first be formed on the photoconductor, then transferred to an intermediate element and then transported to the transfer nip), the position of the receiving material in the transfer nip cannot yet be established with high accuracy at that specific writing instant. Consequently, it is practically impossible in this way to obtain very good register accuracy transversely of the direction of transit. Another disadvantage of this method is that deviations in the sheet transport may be relatively considerable, up to 10 mm deviation from the nominal (required) position. If such deviations have to be absorbed by adapting the image formation to these deviations, considerable tolerances are required for the image-forming units. This makes these units expensive and very bulky.

Method of printing a receiving material, a printer suitable for conducting this method, and a method of adjusting the printer


A steer-by-wire control system that includes a road wheel actuation control system controlling road wheel angles to track a road wheel reference angle and a steering wheel control system producing a steering wheel angle to the road wheel actuation control system, steering feel for the vehicle driver and active steering wheel return. The steering wheel control system further including a steering wheel model matching controller that receives an input signal from the steering wheel control system and an input signal from the road wheel control system and generates a control output signal based on a model-matching control law, wherein the control output signal controls a reaction torque of the steering wheel control system to produce the steering feel for the driver and control the return rate of a steering wheel or a joystick.

1. Field of Invention
The present invention relates generally to a steering system for a vehicle and more particularly to a vehicle steer-by-wire control system using a model-matching strategy.
2. Discussion of Related Art
In a steer-by-wire control system, the traditional steering column, steering shaft, and steering gear are replaced by an electronically controlled actuation system. The actuation system receives a steering command from a controller and accordingly turns the front road wheels using an electric motor. The vehicle driver provides the steering command through a steering wheel control system using a steering wheel or a joystick. As part of a steer-by-wire control system, a steering wheel control system with a force feedback motor actuator provides the direction reference signal for the road wheel actuation system and the familiar steering feel experienced in the conventional steering systems with a mechanical connection. Such a steer-by wire control system can improve a vehicle""s handling performance and stability by providing new features such as adjustable driver steering feel, variable steering effort, variable steering ratio, and active steering wheel return.
FIG. 1 schematically shows a typical steer-by-wire control system 100. As shown in FIG. 1, the steer-by-wire control system 100 includes a steering wheel unit 102, a road-wheel actuation unit 104 and a controller 106. The steering wheel unit 102 includes a steering wheel 108 that is actuated by the driver, a steering wheel angle sensor 110, a steering wheel actuator 112 with electric motor, a motor amplifier 114 and a steering column and connecting shaft 116. The road-wheel actuation unit 104 includes one or more road wheels 118, a road wheel actuator 120 with electric motor, a motor amplifier 122 and a road wheel angle sensor 124. Typically, there are two road wheels 118, one or two road wheel actuators 120 or one or two road wheel angle sensors 124.
The controller 106 controls the steering wheel unit 102 and the road-wheel actuation unit 104 via control algorithms that are implemented in the controller 106. In this system, the required steering functions are realized by using various control system design techniques. In current steer-by-wire control systems, driver""s steering feel is realized by controlling the reaction torque of a DC electric motor actuator 112 attached to the steering wheel 108. Typically, this reaction torque is a function of the steering wheel angle, vehicle speed, and road wheel torque (wheel""s self-aligning moment). It is a challenge for a control system designer to realize the required steering feel by controlling the reaction torque. In addition, in current steer-by-wire control systems, the steering feel and all other steering functions, such as steering wheel returnability, are coupled together. In other words, the controller parameters that affect the steering feel also influence the steering wheel returnability. This coupling between various controlled variables makes the design of a control system and tuning of the controller parameters very difficult and challenging.
A first aspect of the present invention regards a steer-by-wire control system that includes a road wheel actuation control system controlling road wheel angles to track a road wheel reference angle and a steering wheel control system producing a steering wheel angle to the road wheel actuation control system, steering feel for the vehicle driver and active steering wheel return. The steering wheel control system further including a steering wheel model matching controller that receives an input signal from the steering wheel control system and an input signal from the road wheel control system and generates a control output signal based on a model-matching control law, wherein the control output signal controls a reaction torque of the steering wheel control system to produce the steering feel for the driver and the return rate of a steering wheel or a joystick.
In a variation of the first aspect of the invention, the model matching controller has two degrees of freedom and receives a steering wheel angle signal and a road wheel torque signal.
A second aspect of the present invention regards a method of designing a steering wheel model matching controller using a model-matching control methodology. The design of the steering wheel model matching controller requires a reference steering dynamic model which provides a relationship between a steering wheel torque and a steering wheel angle. This reference steering model is representative of a relationship between a steering wheel reaction torque and a steering wheel angle which is applied as a typical evaluation for the steering feel. On the other hand, the steering wheel control system with the steering wheel model matching controller is designed as a closed-loop control system with the steering wheel angle as output and the steering wheel torque as input. With same input and output variables, the steering wheel control system matches the reference steering dynamic model using the different minimization criterions in the model-matching control design such that the steering wheel model matching controller is obtained by minimizing the error between the reference steering model and the steering wheel control system.
In a variation of the second aspect of the invention, the model matching controller with two degrees of freedom is determined using H∞ norm-based minimization criterion
Each aspect of the present invention provides the advantage of improving a driver""s steering feel, and the active steering wheel returnability.
Each aspect of the present invention provides the advantage of improving stability of a closed loop control system.
Each aspect of the present invention provides the advantage of improving the robustness of a steer-by-wire control system to disturbances and system parameter variations.
Each aspect of the present invention provides the advantage of adjusting parameters of a two-degree-of-freedom steering wheel model matching controller independently for improving the steering feel and steering wheel returnability.
Each aspect of the present invention provides the advantage of controlling the feel and rate of return of a steering wheel or joystick independently of one another.

Vehicle steering system control based on a model-matching strategy