A method, apparatus, and article of manufacture for handling NULL values in SQL queries over object oriented data. A two-phase method is used to enable a query evaluator in a two-valued logic environment to properly handle occurrences of NULL values for predicates that involve subqueries, i.e., basic subquery predicates and/or quantified subquery predicates. For basic subquery predicates, negation reduction is performed by applying logical equivalence rules and inverting basic comparators (e.g., transforming < to >=) to eliminate NOTs. Then, transformations are employed for the resulting positive predicates to include NULL value testing, i.e., NULL protection. For quantified subquery predicates, in addition to performing negation reduction, quantified subqueries are converted into existential subqueries. In most cases, this yields a predicate that can be handled using NULL protection transformations for positive predicates. The exception (i.e., a "NOT EXISTS" resulting from the conversion step of a universally quantified subquery) is handled using NULL protection transformations for negative predicates. The evaluation of the NULL tested positive and negative predicates ensures that if a predicate has a NULL value, it is not included in the query result.

1. Field of the Invention
This invention relates in general to systems, methods, and computer programs in the field of processing database queries in database management systems (DBMSs), including relational, hierarchical, and object-oriented DBMSs, and in particular to handling NULL values in SQL queries over object oriented data.
2. Description of Related Art
Databases are computerized information storage and retrieval systems. A Relational Database Management System (RDBMS) is a database management system (DBMS) which uses relational techniques for storing and retrieving data. Relational databases are organized into tables which consist of rows and columns of data. The rows are formally called tuples. A database will typically have many tables and each table will typically have multiple tuples and multiple columns. The tables are typically stored on random access storage devices (DASD) such as magnetic or optical disk drives for semi-permanent storage.
RDBMS software using a Structured Query Language (SQL) interface is well known in the art. The SQL interface has evolved into a standard language for RDBMS software and has been adopted as such by both the American Nationals Standard Organization (ANSI) and the International Standards Organization (ISO). The current SQL standard is known informally as SQL/92.
In RDBMS software, all data is externally structured into tables. The SQL interface allows users to formulate relational operations on the tables either interactively, in batch files, or embedded in host languages, such as C and COBOL. SQL allows the user to manipulate the data.
The definitions for SQL provide that a RDBMS should respond to a particular query with a particular set of data given a specified database content, but the method that the DBMS uses to actually find the required information in the tables on the disk drives is left up to the RDBMS. Typically, there will be more than one method that can be used by the RDBMS to access the required data. The RDBMS will optimize the method used to find the data requested in a query in order to minimize the computer time used and, therefore, the cost of doing the query.
Today, a DBMS can instead be an object-oriented database (OODB), wherein the database is organized into objects having members that can be pointers to other objects. An object can have relationships to other objects. The objects contain references, and collections of references, to other objects in the database, thus leading to databases with complex nested structures.
The integration of object technology and database systems has been an active area of research for the past decade. One important aspect of the integration of these two technologies is the provision of efficient, declarative query interfaces for accessing and manipulating object data. Compared to other aspects of object-oriented database (OODB) technology, such as integrating persistence into object-oriented languages like C++ and Smalltalk, queries were given relatively little attention in the early days of OODB research. Mike Stonebraker, Third Generation Data Base System Manifesto, Computer Standards & Interfaces, 12, December 1991, which is incorporated by reference herein.
In Won Kim, Object-Oriented Database Systems: Promise, Reality, and Future, Proc. 19th International Conference on Very Large Data Bases, Dublin, August 1993, which is incorporated by reference herein, it is pointed out that even today, a number of commercial OODB systems are quite weak in this regard. As the OODB field has developed, however, a number of proposals for OODB query languages have appeared in the database literature including the following publications:
Michael J. Carey, David DeWitt, and Scott Vandenberg, A Data Model and Query Language for EXODUS, Proc. ACM-SIGMOD International Conference on Management of Data, Chicago, June 1988; PA1 Won Kim, A Model of Queries for Object-Oriented Databases, Proc. 15th International Conference on Very Large Data Basses, Amsterdam, August 1989; PA1 Francois Bancilhon, S. Cluet, and C. Delobel, A Query Language for the O.sub.2 Object-Oriented Database System, Proc. 2nd International Workshop on Database Programming Languages, Morgan-Kaufmann Publishers, Inc., Gleneden Beach, June 1989, hereinafter referred to as "BCD89"!; PA1 Jack Orenstein, Sam Haradhvala, and Benson Margulies, Don Sakahara, Query Processing in the ObjectStore Database System, Proc. ACM-SIGMOD International Conference on Management of Data, San Diego, June 1992, hereinafter referred to as "OHMS92"!; PA1 S. Dar, N. Gehani, and H. Jagadish, COL++: A SQL for a C++ Based Object-Oriented DBMS, Proc. International Conference on Extending Data Base Technology, Advances in Database Technology--EDBT '92, Lecture Notes in Computer Science, Springer-Verlag, Vienna, 1992; PA1 Michael Kifer, Won Kim, and Yehoshua Sagiv, Querying Object-Oriented Databases, Proc. ACM-SIGMOD International Conference on Management of Data, San Diego, June 1992; PA1 Tom Atwood, Joshua Duhl, Guy Ferran, Mary Loomis, and Drew Wade, Object Query Language, Object Database Standards: ODMG--93 Release 1.1, ed. R. G. G. Cattell, Morgan-Kaufmann Publishers, Inc., 1993, hereinafter referred to as "ADF.sup.+ 93"!; PA1 Jose Blakeley, William J. McKenna, and Goetz Graefe, Experiences Building the Open OODB Query Optimizer, Proc. ACM SIGMOD International Conference on Management of Data, Washington, D.C., May 1993; PA1 t.A r k PA1 t.A r s.B PA1 t.A r k .fwdarw.(t.A IS NOT NULL and t.A r k) PA1 t.A r s.B.fwdarw.(t.A IS NOT NULL and t.B IS NOT NULL and t.A r s.B) PA1 not (t.A r k).fwdarw.not (t.A IS NULL or t.A r k) PA1 not (t.A r s.B).fwdarw.not (t.A IS NULL or s.B IS NULL or t.A r s.B) PA1 select * PA1 from Emp e PA1 where e.sal>(select avg (e1.sal) from (e.dept.emps) e1) PA1 select * PA1 from Emp e PA1 where e.sal>=all (select e1.sal from (e.dept.emps) e1)
all of which are incorporated by reference herein.
Some commercial object-oriented database systems that offer object query facilities are O2, discussed in BCD89, and ObjectStore, discussed in OHMS92. Each of these object-oriented database systems provides their own flavor of object query language. ObjectStore's query language is an extension to the expression syntax of C++. O2's query language is generally more SQL-like, and has been adapted into a proposed object-oriented database query language standard (ODMG-93) by a consortium of object-oriented database system vendors, ADF.sup.+ 93, which is incorporated by reference herein, but it differs from SQL in a number of respects, Won Kim, Observations on the ODMG-93 Proposal, ACM SIGMOD Record, 23(1), March 1994, hereinafter referred to as "Kim94"! , which is incorporated by reference herein.
Furthermore, it should be noted that SQL3 supports object relational queries, and Illustra Relational Database System includes object oriented SQL extensions. See, the publication by Jim Melton, ed., ISO-ANSI Working Draft: Database Language SQL (SQL3); ISO/IEC SC21 WGS DBL YOW-004 and ANSI XSH2-94-084, ISO.sub.-- ANSI, 1995, hereinafter referred to as "Mel95"!, which is incorporated by reference herein.
In RDBMS software using the SQL-92 query language, columns are of simple atomic types, and columns appear in queries as c or q.c where c is a column of some table and q is a correlation name or range variable. In query languages for Object-Oriented DBMSs, column expressions are replaced with path expressions that allow traversal through pointers, embedded classes and structs, multi-valued collections, and relationships to reach nested attributes.
Mel95 proposes traversal through embedded structures as Abstract Data Types (ADT). For example, if "e" is a correlation, "address" is an ADT of type Address, "zip" is an attribute of address, and the ".." characters are used to express traversal through embedded structures, then "e.address..zip" expresses the traversal through the Address structure to obtain the attribute "zip". It should be noted that the SQL3 draft has been further extended to include support for typed rows, references to rows, and a dereference operator (.fwdarw.).
In RDBMSs, columns of any type can assume NULL (i.e., unknown) values. In RDBMS software, NULL values are properly handled using tri-valued logic (i.e., TRUE, FALSE, or UNKNOWN) for predicates, and SQL-based RDBMSs employ such a logic. The OODB and C++ worlds are different; for example, neither C++ nor the ObjectStore OODBMS nor the ODMG standard has a general notion of NULL values, and their predicates are therefore based upon a two-valued logic (i.e., TRUE, FALSE). Most OODB systems support two-valued logic (TRUE or FALSE), and therefore cannot handle NULL values. See, OHMS92 and Charles Lamb, Gordon Landis, Jack Orenstein, and Dan Weinreb, The Objectstore Database System, Communications of the ACM, 1991, hereinafter referred to as "LLOW91"!; Bjarne Stroustrup, The C++ Programming Language, Addison-Wesley Publishing Co., 1987, hereinafter referred to as "Str87"!; Margaret A. Ellis and Bjarne Stroustrup, Annotated C++ Reference Manual, Addison-Wesley Publishing Co., 1990, hereinafter referred to as "Ell90"!; all of which are incorporated by reference herein.
In the early 1980's, a pre-OODB project the GEM project, discussed in C. Zaniolo, The Database Language GEM, In Proc., ACM-SIGMOD International Conference on Management of Data, 1983, hereinafter referred to as "Zan83"! and S. Tsur and C. Zaniolo, An Implementation of GEM: Supporting a Semantic Data Model on a Relational Backend, In Proc., ACM-SIGMOD International Conference on Management of Data, 1984, hereinafter referred to as "TZ84"!, which are incorporated by reference herein, extended the relational data model and the QUEL query language with entity-relationship features that were quite similar to those found in many of today's object-oriented query languages.
The GEM project was designed as a layer over a RDBMS that added entity-relationship modeling extensions to the relational model. The GEM project, which has a tri-valued logic, was implemented over a RDBMS that had a two-valued logic and did not support NULL values. The GEM project simulated NULL values by requiring an arbitrary value of an attribute to be selected to represent NULL values, as described in Zan83 and TZ84. For example, the value zero could be selected. Then, a test such as (e.sal IS NULL) would be implemented as (e.sal=0).
To translate GEM queries into underlying relational queries, GEM converted its tri-valued logic into two-valued logic, as described in TZ84. The GEM project developed tri-valued to two-valued logic transformations for the following forms of predicate expressions, as described in TZ84:
Here, s and t are correlations over tables, k is a constant, A and B are columns of t and s respectively that can have NULL values, and r is a relational operator among {=, .noteq., <, .ltoreq., >, .gtoreq.}. An example of the first type of predicate above is (e.sal>100), and an example of the second type of predicate above is (e.did=d.no). The previous examples can be scoped by negation: (not (e.sal>100)) and (not (e.did=d.no)) respectively. Negation is determined by counting the number of NOT's from the root of the predicate tree. If the number is odd, the expression is negative, otherwise it is positive. For example, in (not (not e.sal>100)), the subexpression (e.sal>100) is a positive expression, whereas in the expression (not (not (not e.sal>100))), the subexpression (e.sal>100) is a negative expression because it is scoped within an odd number of NOT'S. Positive expressions are replaced as follows:
The predicate (e.sal>100) is transformed into the predicate (e.sal IS NOT NULL and e.sal>100). Similarly, the predicate (e.did=d.no) is transformed into the predicate (e.did IS NOT NULL and d.no IS NOT NULL and e.did=d.no). Negative expressions are replaced as follows:
The predicate (not (e.sal>100)) is transformed into the predicate (not (e.sal IS NULL or e.sal>100)). Similarly, the predicate (not. (e.did=d.no)) is transformed into the predicate not ((e.did IS NULL or d.no IS NULL or e.did=d.no)). If the predicate is not within the scope of negation, the "IS NOT NULL" test guarantees that bindings for which the predicate evaluates to NULL return FALSE. Inversely, if the predicate is within the scope of negation, the "IS NULL" test guarantees that after the application of negation, bindings for which the predicate evaluates to NULL return FALSE.
The GEM project handles simple scalar comparisons, but it does not address predicates involving subqueries that can arise in SQL-92 queries. Subqueries were not an issue for the GEM project, because the GEM query language was based on the QUEL query language, not on SQL. SQL-92 includes predicates of the form: e r Q, and e r .alpha. Q in which e is an expression, r is a relational operator, .alpha. is a qualifier among {ANY, ALL} and Q is a subquery (note: the IN quantified predicate is not detailed here since e IN Q is equivalent to e=ANY Q and e NOT IN Q is equivalent to e.noteq.ALL Q).
The first form of predicate is a basic predicate with a subquery, while the second is a quantified subquery. The following query is an example of a basic predicate with a subquery, and retrieves employees who earn more than the average salary of employees in their departments.
The next query is an example of a query with a quantified subquery and selects employees who have the highest salary of employees in their departments.
Although the GEM query language introduced path expressions (functional joins, in GEM terminology) with the NULL-related semantics, their published transformations in TZ84 did not properly address the handling of NULL values when translating path expressions into QUEL queries. In particular, the transformations presented in TZ84 did not respect the outer-join-like NULL semantics of path expressions that was specified in Zan83.
As noted above, the other shortcoming of GEM was that it did not attempt to handle basic predicates with a subquery or quantified subqueries since GEM was based upon the QUEL query language which does not have subqueries. The SQL-92 query language does include predicates with a subquery including quantified subqueries. SQL-92 also provides an interpretation of the predicates with subqueries if a NULL value is encountered. However, the interpretation specifies when a predicate including a sub-query is NULL, and that is based on tri-valued logic.
The GEM project also did not address NULL pointers. With object-oriented DBMS software, pointer data types are available and attributes of these data types can be NULL. The notions of NULL value and NULL pointer differ in many respects. While NULL values are excluded from most object-oriented data models, they are reintroduced in object-oriented SQL queries where path expressions can include attributes that are NULL pointers. The object-oriented database world, as described in OHMS92 and LLOW91, and the C++ language environment, as described in Str87 and Ell90, do not support NULL values, and their predicates are therefore based upon a two-valued logic. However, both do have pointer types that can be NULL-valued, which leads to NULL-related problems for queries that involve navigation through potentially NULL pointers. Simply ignoring NULL pointers during path expression evaluation could cause the query engine for an object-oriented system (or any other two-valued logic environment having NULL pointers) to fail at run-time. To address this, both the ODMG-93 standard, as described in ADF.sup.+ 93, and ObjectStore, as described in LLOW91 and OHMS92, place the burden of avoiding this problem on the user. Users of these query facilities are expected to include NULL-testing predicates in their queries in order to prevent such cases. If a dereference of a NULL pointer does occur in a query, it is viewed as an error and a run-time exception is raised. This makes queries more complex to specify and introduces ordering dependencies among the query's (possibly many) NULL tests and path predicates.
Thus there is a need in the art for improved methods of handling NULL pointers in SQL queries over object-oriented data.

Handling null values in SQL queries over object-oriented data

International Business Machines Corporation


A construction module having a multi-layered top panel, a multi-layered intermediate panel and a multi-layered bottom panel which are bonded together and desired cavities are provided through one or more of the top panel, intermediate panel and bottom panel.

1. Field of the Invention
This invention relates to the construction art and more particularly to an improved construction module and the method of making the improved construction module.
2. Description of the Prior Art
Construction modules have long been utilized in a variety of applications such as for walls, doors, cabinets, drawer fronts, counter tops and the like. In some applications, such as aircraft, recreational vehicles and similar structures, it is desired that the modules be as light weight as possible and still strong and rigid enough to be suitable for the intended purpose. Further, such modules are often required to be visually attractive so as to provide an appealing combination with the other decor in the structure. Additionally, it is, of course, desired that the construction module be economical to purchase by the end user and therefore be economical to fabricate so that the lower cost is passed on to the customer.
In many such applications there have heretofore been utilized construction modules fabricated from metal coated honeycomb, corrugated aluminum, aluminum skin over ribs or dividers, thin plywood and other such constructions. While many of these modules were light weight, they often were not rigid enough or strong enough for the purpose for which they were intended. Such lack of rigidity or strength often caused distortion of the panel when used for the intended purpose. Also, many of these prior art modules were not visually attractive from all aspects from which they were viewed. For example, even though a decorative cover could be placed on the exterior and/or interior surfaces of such structures such as doors, drawer fronts, cabinet walls and the like which are often viewed from both sides, the edge portions thereof were not as attractive as often desired. Also, many of the prior art construction modules were relatively expensive to the end user, thereby limiting the use thereof.
Thus, there has long been desired a construction module that is light weight, rigid, strong and visually attractive on all surfaces thereof and economical in cost.


Disclosed in a pattern recognition apparatus including a neural net including a plurality of mutually coupled excitatory element-inhibitory element paris. The elements in the neural net are coupled through pair coupling coefficients and an excitatory element coupling coefficient. A teacher signal generator outputs a successive teacher signal Q (t) and its infinitesimal variation .DELTA.Q (t) in accordance with a learning pattern, to apply the output teacher signal and the output small variation to a coupling coefficient controller. The coupling coefficient controller carries out a learning processing in accordance with the teacher signal, so that the coupling coefficients in the neural net are updated. An operation time necessary for a pattern recognition is shortened. In addition, since the learning processing is carried out by only a forward processing on time base, a learning time is also decrease.

1. Field of the Invention
The present invention relates generally to pattern recognition apparatus and pattern learning apparatus and, more particularly, to a pattern recognition apparatus and a pattern learning apparatus employing a neural net including a plurality of excitatory element-inhibitory element pairs. The invention has a particular applicability to a character recognition apparatus.
2. Description of the Background Art
Conventionally, a pattern recognition technology for recognizing image patterns, character or symbol patterns and speech patterns has been known, and recognition apparatus for recognizing those patterns have been developed. A conventional pattern recognition apparatus compares an applied input pattern with a dictionary pattern stored in advance and then detects the distance (for example, "Euclidean distance") or the similarity between the input pattern and the dictionary pattern, thereby determining classification of the applied input pattern. In general, however, characters, speech and the like which are used in practice by human beings are varied even in one classification. Pattern recognition technology in which recognition can be made in accordance with a dictionary pattern without being affected by the variations of characters and speech has not yet been developed.
It is reported that there occurs a significantly dynamic chaotic oscillation phenomenon represented such as by electroencephalogram (or EEG) in brains of creatures, especially of higher-level creatures such as human beings. It seems that a different processing from a recognition processing employing a conventional dictionary pattern is carried out in the brains of higher-level creatures.
In general, it is reported that when recognizing the same kinds of objects or concepts which are individually different and varied though, such higher-level creatures as human beings detect an invariable amount or invariance of the objects or the concepts which is not affected by such variation, and also detect continuity of the variation, thereby recognizing the objects or the concepts. In cognitive psychology, for example, it is reported that a continuous internal operation called "mental rotation" is present in the brains.
Further, it is reported that there occurs oscillation in a neural net including a plurality of mutually coupled excitatory element-inhibitory element pairs as a recognition model. This is described in the article by B. Baird entitled "Nonlinear Dynamics of Pattern Formation and Pattern Recognition in the Rabbit Olfactory Bulb," Physica, Vol. 22D, pp. 150-175, 1986.
In addition, a discovery that a learning of a continuously transformed pattern such as a time-series pattern is available in principle which continuously varies on time base is described in the article by M. Sato entitled "A Learning Algorithm to Teach Spatiotemporal Patterns to Recurrent Neural Networks," Biological Cybernetics, pp. 259-263, 1990. Moreover, another discovery that a lower-dimensional chaotic orbit called "Lorenz Attractor" is also obtained by employing the learning rules of the recurrent networks by M. Sato is also reported in the article entitled "A Learning of Approximation and Chaos of Nonlinear Dynamics by Recurrent Networks," IEICE Technical Report NC90-81, pp. 77-82, 1991. However, those articles have not yet reported that a dynamic orbit is obtained by employing a large number of practical patterns such as images and speech.
For recognizing an input pattern having a great variation such as characters or letters written by human beings, for example, no accurate classification is often made in a recognition method based on a detected correlation distance or similarity. However, it is considered that human beings generally recognize various transformation patterns by a continuous internal operation. Problems of the conventional method based on detection of correlation distances may be solved by employing such a continuous internal operation.
It is pointed out, however, that for realizing the continuous transformation by an oscillation of the neural net, it is difficult to analytically obtain oscillation conditions in the conventional neural net including a plurality of mutually coupled excitatory element-inhibitory element pairs. In addition, since all elements are completely coupled to one another via a number of multipliers in the neural net, a vast amount of calculation cannot be avoided. When a continuous transformation pattern that varies continuously is learned by a neural net, the calculation amount of a temporal inverse processing corresponding to a back propagation of a feedforward net, i.e., a processing that advances backward on time base becomes enormous, resulting in a need for a longer learning time.

Pattern recognition apparatus and pattern learning apparatus employing neural net including excitatory element-inhibitory element pair couplings

ATR Auditory and Visual Perception Research Laboratories


A perimeter is disclosed in which the projection surface of the bowl includes a hemispherical section bounded by a cylindrical perimeter to impart to the interior projection surface of the instrument a "bullet shaped" profile. The perimeter of preferred dimension includes a reduced diameter hemisphere occupying the central 45.degree. of solid angle from the fixated patient's eye. The cylindrical perimeter is joined to the hemisphere and is generated about a cylindrical axis commencing at the spherical center of the hemisphere and extending outward normally from the hemisphere to the point of patient eye placement. The diameter of the cylinder matches and forms a projection continuum with the radius of the hemisphere.

Perimetry is the science of testing the field of view of the eye. Such measurements, particularly if they are taken periodically, can be a useful measure of both the health of the eye as well as tool for the tracking of any eye disease.
Conventional perimeters now in use have large hemispherical bowls forming an interior concave projection surface. The patient being examined is faced forward into the concave hemisphere and positioned with the eye to be examined located at the center of the hemisphere. When the eye to be examined is positioned at the center of the hemisphere, the patient is told to fixate at a fixation target located in the center of the projection surface of the hemisphere. When the patient is properly fixated, eye sensitivity is mapped. Typically, mapping occurs through projection of a light stimulus to typically randomly selected locations on the bowl about the fixation point. When these randomly selected locations are observed, aggregated and "mapped", the perimetry of the eye is described.
Projection of the points of light about the fixation point to the interior of the bowl for observation by the patient occurs either statically or dynamically to determine the boundaries of peripheral vision. During static examination, light is projected onto the surface of the bowl with the patient depressing an indicator when the projected light is observed. During dynamic examination, light is projected onto the surface of the bowl at an angle remote from the fixation point and moved towards the patient's central vision adjacent the point of patient fixation with the patient depressing an indicator when the projected light is observed.
In both kinds of perimetry, the location of the spot on the interior projection surface of the instrument must be precisely identified with respect to the solid angle of patient vision with respect to the point of fixation at the time the patient indicates observation of the light. Only when the correlation is precisely made can a definitive and repeatable perimetric examination be made.
In the past, large hemispherical bowls have been used as the inside projection surface of perimeters. These bowls have an internal spherical radius on the order of 30 centimeters--with the result that instrument dimension is large--on the order of at least 60 centimeters wide, 60 centimeters high and at least 30 centimeters depth.
The use of the large hemispherical bowl has advantages. The distance of the eye to any point on the surface of the bowl onto which the light image is projected remains equidistant from the eye. Further, such bowls lend themselves to having a uniformly illuminated background light projected onto their surface. Finally, determining the angle of projection with respect to point of fixation is a straight forward calculation which readily transfers to the desired perimetric measurement and map.
Unfortunately, the size of such bowls constitutes a serious practical problem. Not only must a rather large instrument be fabricated and shipped, but the same instrument in use has practical difficulties. For example, it is common for such instruments to occupy their own room--or portion of a room. The instrument cannot conveniently be moved. Further, when perimetric measurements are taken, the patient almost always comes to the perimeter--perimetric apparatus is never moved to the patient.


A process is provided for etching a silicon based material in a substrate, such as a photomask, to form features with straight sidewalls, flat bottoms, and high profile angles between the sidewalls and bottom, and minimizing the formation of polymer deposits on the substrate. In the etching process, the substrate is positioned in a processing chamber, a processing gas comprising a fluorocarbon, which advantageously is a hydrogen free fluorocarbon, is introduced into the processing chamber, wherein the substrate is maintained at a reduced temperature, and the processing gas is excited into a plasma state at a reduced power level to etch the silicon based material of the substrate. The processing gas may further comprise an inert gas, such as argon.

1. Field of the Invention
The invention relates to the fabrication of integrated circuits and to the fabrication of photomasks useful in the manufacture of integrated circuits.
2. Background of the Related Art
Semiconductor device geometries have dramatically decreased in size since such devices were first introduced several decades ago. Since then, integrated circuits have generally followed the two year/half-size rule (often called Moore's Law), which means that the number of devices on a chip doubles every two years. Today's fabrication plants are routinely producing devices having 0.35 μm and even 0.18 μm feature sizes, and tomorrow's plants soon will be producing devices having even smaller geometries.
The increasing circuit densities have placed additional demands on processes used to fabricate semiconductor devices. For example, as circuit densities increase, the widths of vias, contacts and other features, as well as the dielectric materials between them, decrease to sub-micron dimensions, whereas the thickness of the dielectric layers remains substantially constant, with the result that the aspect ratios for the features, i.e., their height divided by width, increases. Reliable formation of high aspect ratio features is important to the success of sub-micron technology and to the continued effort to increase circuit density and quality of individual substrates and die. High aspect ratio features are conventionally formed by patterning a surface of a substrate to define the dimensions of the features and then etching the substrate to remove the substrate material. Consequently, reliable formation of high aspect ratio features requires a precise patterning and etching of the substrate.
Photolithography is a technique used to form precise patterns on substrates to be etched to form the desired devices or features. Generally, photolithography techniques use light patterns to expose photoresist materials deposited on a substrate surface to develop precise patterns on the substrate surface prior to the etching process. In conventional photolithographic processes, a photoresist is applied on the material to be etched, and the features to be etched in the material, such as contacts, vias, or interconnects, are defined by exposing the photoresist to a pattern of light through a photolithographic photomask which corresponds to the desired configuration of features. A light source emitting ultraviolet (UV) light, for example, may be used to expose the photoresist to chemically alter the composition of the photoresist. The altered or the unaltered photoresist material is then removed by chemical processes to expose the underlying material of the substrate while the retained photoresist material remains as a protective coating. Once the desired photoresist material s removed to form the desired pattern in the photoresist, the exposed underlying material is then etched to form the features in the substrate surface.
Photolithographic photomasks, or reticles, typically include a substrate made of an optically transparent silicon based material, such as quartz (i.e., silicon dioxide, SiO2), having an opaque light-shielding layer of metal, typically chromium, patterned on the surface of the substrate. The metal layer is patterned to form features which define the pattern and correspond to the dimensions of the features to be transferred to the substrate. Generally, conventional photomasks are fabricated by first depositing a thin layer of metal on a substrate comprising an optically transparent silicon based material, such as quartz, and depositing a photoresist layer on the thin metal layer. The photoresist is then patterned using conventional patterning techniques. The metal layer is etched to remove material not protected by the photoresist, thereby exposing the underlying silicon based material.
In order to achieve current circuit densities, alternating phase shift photomasks are being used to increase the precision of the etching pattern formed on the substrate by increasing the resolution of the light passing through the photomask. Alternating phase shift photomasks are fabricated by the same method described above, but with the additional step of etching the exposed silicon based material to form features that refract the light passing therethrough by one half-wavelength. The half-wavelength light has a greater intensity and improved resolution over the unmodified light, thereby allowing the formation of more precise patterns on the underlying substrate. The refraction of light to produce a proportionally shortened wavelength is based on the composition and thickness of the substrate, and the photomask features are etched into the silicon based material to change the thickness of the material the light passes through, and thus change the wavelength of the light. To modify the light to produce the desired wavelength, the etched features formed in the silicon based material of the substrate must be precisely formed in the substrate with a minimal amount of defects in the feature structure.
Current etching processes for silicon based materials, such as those materials used for dielectric layers in semi-conductor manufacturing, have proven unsuitable for etching features in photomasks. For example, the required processing temperatures, or thermal budgets, of materials, such as photoresists, used in photomask fabrication, are lower than the temperatures experienced in conventional dielectric etching processes. If the thermal budget is exceeded during etching of the photomask, the photoresist layer can detrimentally deteriorate, and consequently cause imprecise features to be etched in the underlying silicon based material, resulting in the formation of defective photomasks.
Additionally, current etch chemistries, such as a mixture of CHF3 and oxygen, used to etch silicon based substrates in photomask fabrication have not produced quality photomasks because the chemistry and the processing conditions have not been able to achieve acceptable feature structure. High quality photomasks require features etched in the silicon based material to have straight sidewalls, a flat bottom, and a angle between the sidewalls and the bottom of the feature, which is referred to as a profile angle, between about 85° and about 90°. If the profile angle is formed with unacceptable tolerances, i.e., angles of less than about 85°, the properties of the light passing through the feature may be detrimentally affected, such as having a less than desirable light resolution, and produce less than desired patterning of the underlying substrate.
One difficulty with achieving acceptable feature structure by current etch chemistries and processing conditions occurs when the CHF3 processing gas produces plasma radicals, such as CHF2, which can polymerize and form deposits on the surfaces of the features formed in the silicon based material of the photomask or on the processing chambers surfaces. The polymer deposits may then flake and produce a particle problem in the chamber and in the etched features. Particle deposition in the features can interfere with the etching process and result in imprecisely formed features. Particle deposition in the features after etching can also lead to interference with the light passing therethrough to produce numerous patterning defects in the subsequent photolithograpic processing of substrates.
Polymer deposits may also form on the inner surfaces of the features, and prevent consistent etching of the features, particularly on the bottom and lower sidewalls of high aspect ratio features. In order to etch the silicon based material of the substrate, the etch process first removes any polymer deposits formed thereon prior to etching the underlying silicon based material. The etching interference caused by the deposited polymers, or passivating deposits, can result in features formed with undesirable structures. For example, it has been observed that the current etch chemistries and processing conditions for etching silicon base materials produce features with uneven or tapering sidewalls, feature bottoms which are convex, concave, or have rough surfaces, and profile angles of less than 85°. Such features detrimentally affect the light passing therethrough which can result in imprecise patterning by the photomask.
The polymer deposits may also detrimentally affect the etching rate of the silicon based materials in comparison to the etching rate of the photoresist materials to produce imprecisely formed features. The etching rate, or removal rate, of one material in contrast to another material is often described as the selectivity of the process to the materials. Polymer deposits formed on the surfaces of the silicon material are etched from the surface of the features prior to the underlying silicon, thereby resulting in the silicon material being etched at a slower rate than would normally occur. A lower etching rate of the silicon material having polymer deposits formed thereon in comparison to the photoresist material etch rate corresponds to a lower selectivity. The effect of a lower selectivity is the premature removal of photoresist material which may produce features which are not etched to the desired dimensions, or which may have tapered dimensions or rounded corners at the top and bottom of the feature. The imprecisely formed features can detrimentally affect the resolution and optical performance of light passing therethrough.
Therefore, there remains a need for a photomask etching chemistry and process which limits polymer formation, minimizes defect formation, and forms features with straight sidewalls, flat, even bottoms, and high profile angles. It would also be desirable if the process provided improved etch selectivity.

This patent is subject to a terminal disclaimer.

Method and apparatus for etching photomasks


Technologies relating to user interfaces for visualizing audio properties. In some implementations, a method is provided that includes the actions of receiving one or more audio signals including digital audio data; generating one or more audio objects, each of the one or more audio objects representing one or more audio signals; and displaying an interface for representing properties of the audio objects, the interface including a region where each location within the region represents two or more audio properties relative to a virtual listener.

The present disclosure relates to user interfaces and visualization of audio data.
Audio signals including audio data can be provided by a multitude of audio sources. Examples include audio signals from an FM radio receiver, a compact disc drive playing an audio CD, a microphone, or audio circuitry of a personal computer (e.g., during playback of an audio file).
When audio signals are provided using microphones, one or more of the microphones are usually associated with particular audio signals, e.g., a musician playing an instrument in an orchestra or a person singing in a band. Additionally, the number of microphones used to capture particular audio signals can be high. In such a setting, it is not uncommon to collect audio signals using microphones from thirty or more sources. For example, a drum set alone may require five or more microphones. Individual groups of instruments can have one or more microphones in common (e.g., in an orchestral setting). Additionally, single instruments are often exclusively associated with one or more microphones.
Audio sources, regardless of the way the audio signals are provided (i.e., whether providing signals using microphones or not), provide signals having different properties. Examples of properties include signal intensity, signal kind (e.g., stereo, mono), stereo width, and phase (or phase correlation, e.g., of a stereo signal).
The process of modifying the properties of multiple audio signals in relation to each other, in relation to other audio signals, or combining audio signals is referred to as mixing. A device for such a purpose is referred to as a mixer or an audio mixer. A particular state of the mixer denoting the relationship of multiple audio signals is typically referred to as a mix.
Generally, an audio mixer has a number of input channels, busses, and output channels. The audio mixer can selectively route the audio signals from particular input channels to one or more output channels. In the mixer, audio signals can be conditioned according to parameters specified by a user. Conditioning can include, for example, adjusting the signal intensity (i.e., the mixer channel output level) of an overall audio signal or adjusting the signal intensity in a specified frequency range. Parameters can include, for example, values for applying a gain to an audio signal (e.g., by increasing or decreasing the overall intensity of the signal) or values for adjusting the signal intensity over a specified frequency range (e.g., as part of an equalization operation).
An audio mixer generally has a number of faders, also referred to as sliders or attenuators. Each fader controls the intensity of an audio signal on an input channel or a group of input channels. This structure exists in software as well as in hardware mixers. Generally, to adjust both the individual intensities of the audio signals and the overall signal intensity of a mix, several adjustments of each fader can be performed in order to achieve a desired result. For example, different faders can be adjusted to set the intensity of each signal at a desired level in relation to the other audio signals and setting the combined audio signal of all the audio sources, i.e., the overall signal intensity.
In a digital audio workstation (DAW), the layout of an audio mixer is usually derived from an analog counterpart and, therefore, usually involves a number of channel strips. For example, an audio source is connected to the "top" of a channel strip and the signal runs through a series of components, e.g., a gain stage, an equalizer, a compressor, one or more aux sends, one or more bus sends, a pan/balance control, and a fader, before being routed to an output or to a combiner, e.g., a stereo summing bus.
Usually, interaction with a user interface of a software mixer involves a cursor controlled through a pointing device, e.g., a mouse, trackball, touchpad, or joystick. Adjustments to a slider control type mixer are made, for example, by positioning the cursor over the knob of a graphic representation of a fader, holding down a button of the pointing device, moving it to the desired position, and releasing the button. Another kind of input device may be employed, e.g., a keyboard, keypad, or dedicated hardware controller. In any case, several adjustments of the faders are used to set the intensity of a number of audio signals relative to each other and for setting the overall signal intensity.
The process of mixing can include a display or visualization of audio properties. Signal intensity, for example, is traditionally conveyed using level meters, such as defined in the standards IEC 60268-10, IEC 60268-17, and IEC 60268-18. An example for a level meter is a VU meter or volume unit meter. A VU meter can be implemented as a magnetoelectric VU meter in which a needle is moved from an initial position towards another position according to the flow of electric current through the meter. Other properties of the signal can also be visualized, e.g., using phase correlation meters, peak level meters, or goniometers.
Properties of audio signals have been visualized, e.g., using analog meters, before the wide use of digital electronic equipment. As a result, for most of the traditional devices for visualization of signal properties a digital equivalent for use in software user interfaces has been devised. Thus, for example, the controls of a digital audio mixer can include a visual representation of analog controls (e.g., an analog VU meter) in order to provide a familiar representation of the device traditionally used.


A new flowmeter which comprises a DP flowmeter and a volume meter in series or in hybrid integrated form. The combination of the readings from the two gives increased metering capabilities.

1. Field of the Invention
The present invention relates to improvements in or relating to flow metering, in particular to a new flow meter and associated method of flow metering for the determination of density, volume and mass flow rates for a single phase flow.
2. Description of Related Art
The metering of fluid flows is a vital part of many engineering processes' control and is therefore directly related to safety and efficiency. In the case of hydrocarbon production wells the fluid flow meter is recording the rate of production and therefore directly recording the monetary flow from the well in question. Clearly, it is vital for industry to have as accurate and reliable a flow meter as possible for many applications. The reality is of course that no meter is ideal for every application and industry is always searching for meters that are cheaper, more reliable, and accurate.
One important class of flow meters are those that are suitable for obtaining a mass or a volume flow rate as a function of density, an example of which is the differential pressure (DP ) flow meter. In the basic sense, a DP flow meter combines Bernoulli's theorem (i.e. the conservation of energy of a fluid flow) and the conservation of mass of a fluid flow between two points in a flow, and the difference in pressure between these two points is measured so that a mass or volume flow rate can be expressed as a function of this differential pressure and the fluid density. A DP meter comprises an obstruction to fluid flow and means for measuring the pressure change caused by the obstruction, giving associated flow rate equations for either volume flow rate or mass flow rate wherein these respective flow rate equations are both functions of density. The obstruction is defined by a "primary element" which can be either a constriction formed in the conduit or a structure inserted into the conduit. The primary element can be for example a Venturi constriction, an orifice plate, a cone shaped element or other form.
Pressure tappings are inserted up stream from the primary element and at or in the vicinity of the primary element and the pressure difference between the two points is monitored. The primary element causes a drop in pressure, and it is customary to measure the pressure at the point of the conduit that corresponds to the lowest pressure. For a Venturi meter, this measurement point will correspond to the "throat" of the primary element, that is, the point of the element that has the minimum cross sectional area. (If the precise position of the lowest pressure is not known for a particular geometry of primary element (as for example in the case of Orifice Plate Meters) it is customary to select a stated position where it is known the pressure will be significantly lower than the pressure tapping up stream of the primary element.)
A further example of a type of meter that is suitable for obtaining a mass or a volume flow rate as a function of density is the so called target meter. In its basic sense, a target meters measures the drag force applied to an object inserted into the fluid on a supporting strut. The drag force is a direct function of the flow's dynamic pressure so when the drag and the mass continuity equations are combined the result is that a mass or volume flow rate can be expressed as a function of the measured drag force and the fluid density.
Another type of flow meter is a velocity flow meter, which in its broadest sense can be taken to be any meter that has means to estimate the volume flow rate of a fluid flowing through a conduit. Velocity flow meters are also sometimes called "linear" or "volume" flow meters, which are hereby taken to be equivalent expressions. These flow meters are not dependent on density—they give no mass flow or density output. These meter designs directly estimate the volume flow rate of the fluid regardless of the fluid density. Examples of volume flow meters include Vortex meters, Positive Displacement (P D) meters, Ultrasonic meters and Turbine meters. With the exception of the P D meter these mentioned volume meters are sometimes described as velocity meters as they give the average velocity of the fluid which in turn can be expressed as a volume flow rate as the cross sectional area of the pipe is known. (The P D meter measures the volume flow rate directly).
Currently, mass flow can only be measured directly by a Coriolis meter. Coriolis meters arc, relative to the pipe size for which they arc used, large, heavy, and expensive pieces of equipment. The size problem makes them impractical for use at line sizes above 12″. Also, for practical applications (oil rig, refinery, pharmaceutical plants etc) there are pumps and valves and other components that cause vibrations in the pipe that can sometimes interfere with the frequency readings read by a Coriolis meter. This noise needs to be filtered out of the Coriolis meter readings, but sometimes (depending on frequency ranges) the noise cannot be filtered out as it's too close to the meter's frequency and the reading is drowned out. Therefore, Coriolis meters are not ideal mass meters but they are all industry has that measures mass flow directly. A Coriolis meter also indicates the density of the flowing fluid and through this, one can estimate the volume flow rate.
When a Coriolis meter is not chosen to measure mass flow and density, the density of the fluid has to be calculated directly. This is done by pressure and temperature measurements and for the properties of the known fluid a "P VT" (i.e. Pressure, Volume and Temperature) calculation is carried out to predict the density. This relies on the knowledge of the fluid composition and fluid properties being accurate. As this can change periodically in flows such as oil and natural gas production this is not ideal as the density measurement is therefore not in real time but based on periodic spot checks on fluid composition. If the fluid composition changes it is not discovered that the fluid density prediction is wrong and hence the meters mass flow rate prediction is wrong until the next sample is taken and analyzed.
As an example (it is to be understood that the scope and application of the following invention is not limited to any particular industry), in natural gas flows, a gas chromatograph takes a sample and analyses the gas components. It then feeds that information to a P VT calculation that predicts the gas density from the measured pressure and temperature from the meter. Carrying out this process with the best known equipment in the shortest possible time is said to take around six minutes to produce a gas density. In many cases it takes longer than six minutes. When that is done it automatically starts again. This is the density the flow computer uses to calculate the mass flow rates from the installed meters until it is up dated every gas chromatograph/P VT cycle. If there arc fluctuations in the gas composition (and hence density) at a frequency greater than the frequency of the P VT up date this system does not see it very clearly. The calculation is a static reading of that particular grabbed fluid sample and the system is assuming that is representative of the flow over a period of time. This inaccuracy can be significant. A monitor that gives more up to date predictions of density could be very valuable to industry.
When the density is calculated it can then be used in conjunction with a velocity meter to predict the mass flow rate. Alternatively, the density can be substituted into the DP meter equation for mass and the DP meter equation for volume to give mass and volume flow rates. However, industry does not have a way of checking the density prediction of the P VT calculation and also has no way of measuring mass flow without using a P VT calculation or a Coriolis meter.

Hybrid flowmeter that includes an integral vortex flowmeter and a differential flow meter


A method for cleaning a plasma etch chamber is described which can be carried out by first terminating an etch process by stopping a process gas flow into the chamber, then maintaining a RF power in the etch chamber, and flowing a cleaning gas consists of at least one inert gas and oxygen through the chamber at a flow rate higher than the flow rate for the process gas for a length of time sufficient to evacuate substantially all the contaminating byproducts formed by the process gas. A suitable cleaning gas contains at least one inert gas of Ar, He, or N.sub.2 mixed with O.sub.2. A sufficient length of time for the cleaning process is at least 5 seconds, and preferably at least 10 seconds.

In the fabrication of semiconductor integrated circuit (IC) devices, various device features such as insulation layers, metallization layers, passivation layers, etc., are formed on a semi-conducting substrate. It is known that the quality of an IC device fabricated is a function of the processes in which these features are formed. The yield of an IC fabrication process, which in turn is a function of the quality of the device fabricated and a function of the cleanliness of the manufacturing environment in which the IC device is processed.
The ever increasing trend of miniaturization of semiconductor IC devices occurring in recent years requires more stringent control of the cleanliness in the fabrication process or the processing chamber in which the process is conducted. This leads to a more stringent control of the maximum amount of impurities and contaminants that are allowed in a process chamber. When the dimension of a miniaturized device approaches the sub-half-micron level, even a minutest amount of contaminants can significantly reduce the yield of the IC manufacturing process. For instance, the yield of the process can be drastically reduced by the presence of contaminating particles during deposition or etching of films which leads to the formation of voids, dislocations or short-circuits resulting in performance and reliability problems in the IC devices fabricated.
In recent years, contamination caused by particles or films has been reduced by the improvements made in the quality of clean rooms and by the increasing utilization of automated equipment which are designed to minimize exposure to human operators. However, even though contaminants from external sources have been reduced, various contaminating particles and films are still generated inside the process chamber during the processing of semiconductor wafers. Some possible sources of contamination that have been identified include the process gases and liquids, the interior walls of the process chambers and the mechanical wear of the wafer handling equipment. The chances of generating contaminating particles are also increased in process chambers that are equipped with plasma enhancement. Various chemically reacted fragments are generated from the processing gases which include ions, electrons and radicals. These fragments can combine and form negatively charged particles which may ultimately contaminate a substrate that is being processed in the chamber. Various other materials, such as polymeric films may also be coated on the process chamber walls during plasma processing. The films may dislodge and fall from the process chamber walls when subjected to mechanical and thermal stresses such that they fall onto the wafers that are being processed.
An example for illustrating chamber wall contamination is the etcher 10 shown in FIG. 1. Etcher 10 is a plasma etching chamber that is equipped with magnetic field enhancement generated by an upper rotating magnet 12 and a lower rotating magnet 14. The plasma etcher 10 includes a housing 16 that is typically made of a non-magnetic material such as aluminum which defines a chamber 20. A substrate holder 22 which is also a cathode is connected to a RF generator 24 which is in turn connected to a gas inlet (or showerhead) 26. The showerhead 26 also acts as an anode. A process gas 28 is supplied to chamber 20 through the gas inlet 26. A semi-conducting substrate 30 to be processed is positioned on the substrate holder or cathode 22.
The semi-conducting substrate 30 is normally held against the substrate holder 22 by a clamp ring 32. During a plasma etching process, a semi-conducting wafer 30 heats up significantly during the process and must be cooled by a cooling gas from a cooling gas supply (not shown) such that heat can be transferred to a water cooled wafer holder 36. The function of the clamp ring 32 is also to hold the substrate 30 down against the pressure generated by the cooling gas. An exhaust port 34 which is connected to a vacuum pump (not shown) evacuates the chamber. During an etching process, the upper rotating magnet 12 and the lower rotating magnet 14 function together to provide a magnetic field inside the process chamber 20.
In a conventional cleaning process for the plasma etch chamber 10, a cleaning gas supply is first flown through the gas inlet port 26 into the chamber 20 and then, the RF generator 24 is turned on. The cleaning procedure is conducted after a predetermined number, e.g., between 100.about.500 of wafers have been processed in chamber 20. A plasma of the cleaning gas ions is formed in the space between the showerhead 26 and the wafer holder 32 to loosen the contaminating particles and films from the chamber walls and the showerhead 26 or the upper electrode.
In an etching process for polysilicon or metal, a chlorine etching gas is frequently used. On the other hand, the etching gas used for oxide or nitride is frequently fluorine gas. During a plasma etching process, the reactive plasma ions have a high energy level and therefore can easily combine with any available chemical fragments or elements in the chamber to form contaminating particles or films. For instance, in a metal etching process, the elements frequently seen in the etch chamber includes C, H, N, O, Al, Ti, TiN and Si. Different elements such as C, N, O, Br, Si and W are seen in a polysilicon etch chamber. The contaminating particles or films formed by often volatile chemical fragments or elements during an etching process often float or suspend in the chamber due to the interaction with high energy plasma ion particles when the RF power is on. The phenomenon of the floating or suspended particles can be explained by the fact that the particles have higher energy and temperature while suspended in a plasma cloud. However, at the end of a conventional etching process, the RF power is switched off which leads to the sudden loss of energy in the suspended contaminating particles and causing them to fall or stick to the chamber walls or the upper electrode. This is shown in FIGS. 2A and 2B.
FIG. 2A shows a simplified etch chamber 40 equipped with a chamber cavity 42 defined by chamber walls 44. A process gas inlet 46 is used to flow a process gas into the chamber cavity 42. An upper electrode 48 and a lower electrode/wafer holder 50 are used to supply RF power to the chamber and to produce plasma ions. A gas outlet 54 is used to evacuate the process gas from the chamber cavity 42 at the end of the etching process. During the etching process, contaminating particles 52 formed as etch byproducts are buoyant and are suspended in the chamber cavity 42. A wafer 56 is supported by the wafer holder 50 for processing.
After a conventional etching process is conducted, the RF power is turned off. The suspended, contaminating byproducts or particles 52 are easily deposited on chamber walls 58, upper electrode 48 and wafer 50. These contaminating particles (or films) are frequently formed of a carbon or chlorine containing polymeric material and when adhered to the chamber wall 58, are very difficult to remove from the chamber. Conventionally, a wet cleaning process must be conducted after approximately 2,000.about.3,000 wafers have been processed in the etch chamber 40. The wet cleaning process is carried out by using cleaning solvent such as IPA, deionized water, combination IPA/deionized water or the more volatile acetone. The wet cleaning process is very time consuming and sometimes hazardous to the maintenance personnel due to the toxic nature of the contaminating byproducts and the highly volatile cleaning solvent used. A wet cleaning process causes a down time to an etcher sometimes as long as one full day.
It is therefore an object of the present invention to provide a method for cleaning a plasma enhanced process chamber that does not have the drawbacks or shortcomings of the conventional cleaning methods.
It is another object of the present invention to provide a method for cleaning a process chamber for etching polysilicon or metal that can be incorporated into the process recipe for in-situ cleaning of the chamber.
It is a further object of the present invention to provide a method for cleaning a plasma enhanced process chamber by maintaining a RF power in the chamber after the completion of the etching process to facilitate cleaning of the chamber.
It is still another object of the present invention to provide a method for cleaning a plasma enhanced process chamber by first stopping a process gas flow while maintaining a RF power in the chamber and then flowing a cleaning gas at a high flow rate through the chamber.
It is another further object of the present invention to provide a method for cleaning a plasma enhanced process chamber by maintaining a RF power in the chamber and utilizing a cleaning gas consists of at least one inert gas and oxygen.
It is yet another object of the present invention to provide a method for cleaning an etch chamber in which etch gas of chlorine or fluorine is used by purging through the process chamber under a RF power a cleaning gas consist of an inert gas and oxygen.
It is still another further object of the present invention to provide a method for cleaning a plasma enhanced process chamber by maintaining a RF power in the chamber and flowing a cleaning gas consist of at least two gases selected from Ar, He and N.sub.2 and O.sub.2 into the chamber.
It is yet another further object of the present invention to provide a method for cleaning an etch chamber by flowing through the chamber under RF power a cleaning gas at a high flow rate by using a full pumping speed of a vacuum pump.

Taiwan Semiconductor Manufacturing Company, Ltd


This invention pertains to a method for varying the level of an alerting indicator of a radiotelephone while an incoming call is being received, and also to a radiotelephone that operates in accordance with the method. The method includes a first step of operating a user interface (22) for inputting information to a controller (20) of the radiotelephone, the information specifying that an alerting indicator volume be reduced or muted. In response to the inputted information, a second step reduces the alerting indicator volume. An alerting indicator volume that has been reduced is increased upon the termination of the incoming call signal, upon the elapse of a predetermined time period and/or in response to information inputted to the controller (20) via the user interface (22), which information specifies that the alerting indicator volume be increased. In one embodiment of the invention, the alerting indicator volume is maintained at a reduced value until information is input to the controller (20) via operation of the user interface (22), which information specifies that the alerting indicator volume be increased. In response to the inputted information, the alerting indicator volume is increased. The invention may be used in radiotelephones employing non-audio alerting indicator devices for indicating an incoming call, such as vibrating devices.

It is known in the art to provide a radiotelephone with an adjustable alert tone volume, as evidenced by Nokia Mobile Phones owner's manuals N201 and 232. The alert tone is analogous to the ringing of a conventional telephone, and notifies the user of a reception of an incoming call. Such radiotelephones, however, permit a user to select an alert tone volume only during the time when no incoming call is being received by the radiotelephone. For current radiotelephones, in order to quiet an alert tone during the reception of an incoming call a user must either answer and thereafter terminate the call by depressing appropriate keys of a user keypad, or simply turn off the radiotelephone power. These methods, however, are inadequate for a user who does not wish to terminate the call, but desires to either answer the call later, or have the call diverted to a message storage system or other telephone number. To circumvent these problems, some radiotelephones have been provided with a silent service facility, which may include visible alerts such as a flashing LED or display. However, unless the user is viewing the phone, an incoming call may be missed.

Radiotelephone enabling adjustment of alerting indicator volume/level during incoming calls


An aircraft locking system (11) is provided that avoids inadvertent or deliberate operation of an aircraft exit opening means (50) during take-off roll, in-flight, or during landing. The aircraft locking system includes means for determining whether engines of the aircraft are running (12), means for determining thrust lever position (14), means for determining whether the aircraft is in an air mode or a ground mode (16), and means for determining whether a predetermined number of service/entry doors are closed (18). Means for generating a lock/unlock signal (32, 40) are responsive to the engine running determining means, the thrust lever position determining means, and the service/entry door-closed determining means.

1. Field of the Invention
This invention relates to aircraft exit door locking systems and, more particularly, to an automatic flight locking system for avoiding inadvertent or deliberate operation of an airplane exit opening means during take-off roll, in-flight, or landing.
2. Background Information
Inadvertent or deliberate opening of an aircraft exit during take-off, in-flight, or during landing can result in severe damage to the aircraft as well as injuries to crew members or passengers. For example, an exit door opened in-flight may be subjected to air and inertial loads that are sufficient to cause door separation and can result in damage from impact of the door with the aircraft structure, ground personnel, or property. Also, opening a door on a pressurized airplane can result in a decompression, thereby resulting in potential harm to passengers and the airplane structure. Of particular concern are doors that are not quickly and easily accessible to cabin crews, such as emergency exits like over-wing hatches and upper-deck canopy doors.
Currently, Federal Aviation Administration (FAA) Advisory Circular (AC) 25.783-1 states that it is not considered acceptable to rely solely on cabin pressure to prevent an inadvertent opening of doors in-flight due to door-opening incidents during unpressurized flight, such as during taxiing and landing. The FAA AC also states that all doors should therefore incorporate features in the locking mechanism that provide positive means for preventing the door from vibrating open or from being opened inadvertently by passengers or crew members. Further, the FAA AC states that this positive means should be effective throughout the approved operating envelope of the aircraft, such as takeoff, flight, and landing, and should not complicate the opening of passenger emergency exits under emergency conditions.
Prior attempts to prevent the inadvertent opening of aircraft exits have monitored air/ground logic and dynamic environmental parameters, such as inertial pitot logic, reference logic, and wheel speed. For example, see U.S. Pat. No. 4,915,326. Such a lock system requires sophisticated sensors and processing capabilities to gather and process the dynamic environmental data in order to perform its locking function. This dynamic environmental data is not readily or easily obtained on older or less sophisticated aircraft.
Thus, there is an unmet need in the art for an automatic flight lock system that avoids inadvertent or deliberate operation of an airplane exit opening means during take-off roll, in-flight, or during landing.

Engine parameter activated airplane exit locking system


A analyte species separation system including a fluid flow field disposed between confining surfaces, the flow field having a first flow component flowing in a first direction and a second flow component flowing in a second, transverse, direction, and an electric field configured to cause analyte species to move in the separation flow field at least in a direction opposite to the first flow component, a analyte injection channel in fluid communication with the flow field and an analyte separation target channel or otherwise a collector in fluid communication with the flow field, the system configure so that an analyte species in an analyte sample injected into the flow field traverses at least a portion of the flow field toward the collector target channel with said second flow component, enabling analyte species separation parallel to the first direction and movement in the second direction so that analyte species having mobilities outside a selected mobility range do not enter the target channel and/or an analyte species having a selected mobility is directed into the target channel.

1. The Field of the Invention
The present invention relates generally to separation of analyte species in an analyte sample. More particularly, the present invention relates to a fraction collector configured for separating and collecting an analyte species from an analyte sample containing a plurality of analyte species and enabling such a separation on a continuous basis if desired.
2. Description of Related Art
The ability to separate a particular analyte species from an analyte sample is a common requirement in biological research. Likewise being able to separate a particular substance from a mixture of substances is often a requirement in pharmaceutical manufacturing. For example, the ability to separate an individual protein from a mixture of proteins is desirable in research and in the manufacturing of certain medicaments. For convenience, the terms "analyte" and "analyte species" will be used herein to refer to a sample containing a plurality of different substances, and the individual substances, respectively. Typically, these will be substances comprising molecules having a net charge (e.g. protein molecules, amino acid molecules, and DNA molecules).
HPLC, gel electrophoresis and CE typically offer a "single pass" means of separating a mixture of substances into separate substances or isolating a particular substance or group of substances. However, it is generally not efficient to do multiple separations to increase the quantity of obtained sample of one substance separated out from the sample mixture. A more efficient method is to provide a continuous separation. One method of doing this is called "Simulated Moving Bed" or SMB, which consists of switching segments of a conventional separation column in such a manner that the apparatus will allow a continuous fluid mixture including analyte to be flowing into one end of the column, and a continuous flow of a separated analyte species from the column output, while a second output discharges the remainder of the fluid mixture. Most SMB apparatus configurations comprise many packed columns, each similar to an HPLC column, for example, which are switched sequentially at time intervals to simulate a counter-flowing moving bed.
For continuous separation of analyte species, e.g. individual proteins, in complex analyte mixtures, conventional SMB processes do not work well because the HPLC columns have limited resolution, and conventional known substitutes for this method are likewise limited. Even for relatively simple analyte sample mixtures, the stationary phases used in a conventional SMB require a relatively large amount of development time to optimize the separation; and, in some instances, the stationary phase in the columns becomes very expensive.


The present invention is directed to 2,6-disubstituted piperidine and piperazine analogs having the following general formula:

Alpha-Lobeline (lobeline), a lipophilic nonpyridino, alkaloidal constituent of Indian tobacco, is a major alkaloid in a family of structurally-related compounds found in Lobelia inflata. Lobeline has been reported to have many nicotine like effects, including tachycardia and hypertension (Olin et al., 1995), hyperalgesia (Hamann et al., 1994) and improvement of learning and memory (Decker et al., 1993). Lobeline has high affinity for nicotinic receptors (Lippiello et al., 1986; Broussolle et al., 1989). However, no obvious structural resemblance of lobeline to nicotine is apparent and structure function relationships between S(−)-nicotine and lobeline do not suggest a common pharmacophore (Barlow et al., 1989). Also, differential effects of lobeline and nicotine suggest that these drugs may not be active through a common CNS mechanism, even though lobeline has been considered a mixed nicotinic agonist/antagonist.
Lobeline evokes dopamine (DA) release from rat striatal slices. However, lobeline evoked DA release is neither dependent upon extracellular calcium nor is it sensitive to mecamylamine, a noncompetitive nicotinic receptor antagonist. Thus, lobeline evoked DA release occurs via a different mechanism than does nicotine to evoke DA release (Teng et al., 1997, 1998; Clarke et al., 1996). In this respect, lobeline also inhibits DA uptake into rat striatal synaptic vesicles via an interaction with the dihydrotetrabenazine (DTBZ) site on vesicular monoamine transporter-2 (VMAT2), thus increasing the cytosolic DA available for reverse transport by the plasma membrane transporter (DAT) (Teng et al., 1997, 1998). Thus, lobeline interacts with nicotinic receptors and blocks nicotine-evoked DA release, but also interacts with DA transporter proteins (DAT and VMAT2) to modify the concentration of DA in the cytosolic and vesicular storage pools, thereby altering subsequent dopaminergic neurotransmission.
Currently, drug discovery is focusing on neuronal nicotinic receptors (nAChRs) as novel targets for the development of therapeutic agents for a wide variety of central nervous system (CNS) diseases including, drug addiction, neuroendocrine, neuropsychiatric and neurological diseases, memory and learning disabilities, eating disorders, and the control of pain, as well as cardiovascular and gastrointestinal disorders. Nicotinic receptor antagonists have good potential as therapeutic agents, since they offer another means of modulating nicotinic receptor function. Nicotinic agonists rapidly desensitize these receptors, essentially inhibiting their function. Thus, inhibition of nicotinic receptor function may be the action, which confers clinical utility, indicating that nicotinic receptor antagonists could also be beneficial in the treatment of diseases for which nicotinic agonists are currently being developed. For example, schizophrenia and drug abuse have both been associated with hyperactivity of CNS dopaminergic systems, and inhibition of nicotinic receptors may be advantageous in reducing such hyperactivity. Furthermore, the availability of subtype-selective nicotinic receptor antagonists will be invaluable agents in both basic and clinical research, with regard to both the treatment and diagnosis of disease. Finally, subtype-selective antagonists will define the role of specific nicotinic receptor subtypes in both physiological function and disease states.
The action of many neuropharmacologically therapeutic agents involve the modulation of dopamine (DA), norepinephrine (NE) and serotonin (5-HT) release, uptake and storage within its respective terminals in the central nervous system (CNS). Most neurotransmitters are stored in synaptic vesicles, which are prominent features of nerve terminals. Concentration into vesicles appears to be responsible for maintaining a ready supply of neurotransmitter available for neuronal exocytotic release into the synaptic cleft. Vesicles also serve the role of protecting the neurotransmitter from metabolic breakdown. One transport site on the vesicle membrane is the vesicular monoamine transporter-2 (VMAT2), whose role is to transport transmitter from the cytosol into the synaptic vesicle. Dihydrotetrabenazine (DTBZ), a ligand structurally related to methoxytetrabenazine (MTBZ), has been used as a radiolabel to probe the interaction of drugs with VMAT2. Both DTBZ and MTBZ act at the same site on VMAT2. Once the neurotransmitter is released from the terminal into the synaptic space, it interacts with postsynaptic receptors and subsequently is taken back up into the terminal via the plasma membrane transporter (e.g., the dopamine transporter [DAT] and/or the serotonin transporter [SERT]). Thus, transporter proteins modify the concentration of neurotransmitter in the cytosolic and vesicular storage pools, thereby having the ability to alter subsequent neurotransmission.

2,6-disubstituted piperidines and piperazine compounds

Abstract: which are used to treat diseases of the central nervous system, drug abuse, and withdrawal therefrom as well as treating eating disorders.

University of Kentucky Research Foundation


A medical training simulator includes contact-less sensors and corresponding detection objects, configured to enable sensor data collected during a training exercise to be used to evaluate the performance of the training exercise. The simulator includes a simulated anatomical structure, at least one contact-less sensor, and at least one detection object. During a training exercise, a spatial relationship between the contact-less sensor and the detection object produces data for evaluating performance of the training exercise. Either the contact-less sensor or the detection object is embedded in the simulated physiological structure, while the other is included in either a support for the simulated physiological structure, or as part of a tool used during the training exercise. Many types of contact-less sensors can be employed, including capacitance sensors, impedance sensors, inductive sensors, and magnetic sensors.

The use of simulated physiological structures for training medical students and for providing skill training to practicing physicians is widespread. Although cadavers have traditionally been beneficially employed for this purpose, cadavers are not always readily available and are not well suited for all types of training.
Simulated physiological structures should preferably be usable multiple times and should provide a realistic training experience corresponding to what the trainee would experience if performing a procedure on an actual patient. The need for such simulators is significant, because they can provide valuable training that will lead to more effective treatment of patients.
The use of a training model (such as a cadaver, an animal, or a simulator) is desirable to properly prepare a student or physician to perform procedures on a variety of patients. While anatomy follows general rules, variations based on sex, age, height, and weight are the norm. A surgical student should not just blindly follow directions such as "make an incision four inches long and two inches deep, starting at the navel." Normal variations, such as the amount of body fat on a specific patient, will significantly change the depth of fat tissue that must be incised to reach an internal organ. Surgeons must rely on their knowledge of general anatomy, and evident cues (e.g., visually noting whether the patient has a low or high percentage of body fat, or whether the patient is a child, an adult, a female, etc.) to determine the correct location and other variable parameters, before performing a procedure on a specific patient. The use of cadavers, animal models, and anatomically correct simulators enable surgical students and physicians to apply their knowledge of anatomy to develop experience in assessing these factors, so as to properly determine the proper parameters to be applied when executing a procedure on a live patient.
To provide the desired level of realism, a simulated physiological structure used for training medical personnel should both tactilely and visually resemble the anatomical structure being simulated. Even if a simulated physiological structure having simulated tissue faithfully portrays finer details of an actual physiological structure and provides a realistic tactile sensation during a simulated procedure, the few prior art simulators that may both tactilely and visually resemble the anatomical structure being simulated do not include means for producing objective and measurable results that can be used to evaluate how well a simulated procedure is performed. Clearly, it would be desirable to employ a simulated physiological structure that is able to provide a realistic tactile sensation during a simulated procedure, and which is also able to provide an objective indication that can be used to evaluate how well a simulated procedure was executed.

Medical training simulator including contact-less sensors


A video data network device arranged to receive a video signal and an associated synchronisation signal and to launch video data packets representing the video signal onto a packet-based data network comprises means for detecting whether the video signal is synchronised with the synchronisation signal; and means for launching data onto the network indicating whether the video signal is synchronised with the synchronisation signal.

1. Field of the Invention
The present invention relates to packet-based video networks.
2. Description of the Prior Art
It is known to link video and audio devices in a television studio together using a switching device, typically a cross point switch.
A system has been proposed which links audio and video devices in a studio by a packet-switched local area network, for example an Ethernet network, operating with a known protocol such as Internet Protocol (IP). However most, if not all, current video and audio equipment used in studios is not equipped to operate with such a switched network operating according to such a protocol.
The audio and video devices used in a studio include cameras, editors, audio mixers, video tape recorders (VTRs) and play-out switches amongst other examples. It is also known to use monitors to view video which is being played out or to preview on monitors video which is available to be played out.
One of the obstacles to providing circuit-switched studio functionality in a packet-switched network is that video and audio signals have stringent timing and synchronisation requirements. Typically, a video source will be locked to at least two timing signals, a bit clock and a frame synchronisation clock. Copending applications 0204242.2 and 0307459.8 deal with techniques to allow synchronisation of both individual data bits and video frames over a packet-based network. In particular, at a video source node on the network, a video signal is synchronised to reference clock signals. At a receiving node elsewhere on the network, a local clock is synchronised to the reference clock signals, and video data packets received from the source node are handled in synchronism with the local clock.

Packet-based video network indicating video signal synchronization and methodology thereof


A monolithically loaded microstrip antenna is provided for a communications function, such as a cellular telephone base station. The antenna includes a ground plane and a group of stacked, planar elements. A director element having a rectangular configuration together with monolithic load tabs is connected to a feed line and spaced above the ground plane. A first director element is spaced above the driven element and has lesser length and width dimensions than the driven element. A second director element is spaced above the first director element and likewise has lesser length and width dimensions than the driven element. A group of eight of the antennas are positioned in a column to form an antenna array which has substantial vertical polarization, a relatively wide horizontal beam width, approximately 60.degree. and a relatively narrow vertical beam width, approximately 8.0.degree.. The antenna array has a center frequency of 885 Mhz and a bandwidth of approximately 230 Mhz.

Microstrip antennas have come into widespread application because of the compact size and ease of fabrication. The conventional microstrip antenna consists of a rectangular patch metal element positioned on a grounded dielectric substrate. The thickness of the substrate is typically much less than the wavelength at which the antenna operates. Microstrip antennas are particularly desirable for use in an antenna array. Microstrip antennas, for example, are shown in U.S. Pat. Nos. 4,835,538 to McKenna, 4,131,893 to Munson et al., 4,131,894 to Schiavone, and 4,821,040 to Johnson et al. A disadvantage of a typical microstrip antenna is its narrow bandwidth, typically 3% and low gain, such as 7.0 db. It would be desirable to maintain the advantages of a microstrip antenna while improving its bandwidth and gain.
A number of approaches have been made to improve the bandwidth of microstrip patch antennas, but little attention has been paid to improving the radiation characteristics, such as directivity and gain. A number of approaches have been made to broaden the antenna bandwidth of microstrip antennas. These are a thick dielectric substrate microstrip patch and a multi-layer parasitically coupled microstrip patch antenna.
A thick dielectric substrate microstrip patch antenna such as shown in U.S. Pat. No. 4,835,538 as FIG. 1 comprises a radiating patch fabricated on a relatively thick dielectric substrate. Such an antenna structure can produce a bandwidth of approximately 8% at 1.5:1 VSWR (voltage standing wave ratio).
One approach to improving the bandwidth of a microstrip patch antenna is a design in which one or more parasitic elements are employed to improve the antenna bandwidth. An example of such an antenna structure is a capacitively coupled resonator radiator shown in U.S. Pat. No. 4,835,538 as FIG. 2. This includes a stacked array of two elements with only the lowermost element being fed. RF (radio frequency) energy is radiated from the driven element to create currents that flow on the parasitic element, which is larger than the driven element. This antenna structure produces a maximum bandwidth of approximately 14% at 2:1 VSWR. This is insufficient in many applications. Further, the VSWR obtained in this design is too high for the output stages of many RF transceivers and this can result in system inefficiency due to excessive return loss.
A further example of a multi-layer parasitically coupled microstrip patch antenna is also shown in U.S. Pat. No. 4,835,528 as FIG. 4. This antenna includes a stacked array of three circular elements in which the lowermost element is fed. The lowermost element is the smallest and the upper parasitic elements are the largest. These elements are printed on copper clad printed circuit board and are separated and supported by honeycomb dielectric material. The bandwidth obtained from this type of antenna structure ranges from 20-30% at 2.0:1 VSWR or about 18% at 1.4:1 VSWR. This bandwidth is broader as compared to conventional microstrip patch antennas, but, this antenna structure has a dual linearally polarized radiation characteristic. As a result, the RF energy is radiated in both the vertical and horizontal polarizations and this is not applicable or suitable in many applications, such as radio communication systems, which use vertical polarization only.
An antenna structure which has stacked radiator elements is shown in U.S. Pat. No. 4,131,892 to Munson et al.
A microstrip antenna and array of microstrip antennas is described in U.S. Pat. No. Re. 29,911 to Munson.
In view of the above state of development for microstrip antennas and the requirements for antenna applications, such as radio communications for cellular telephones, there is a need for an antenna, and corresponding array of antennas, which has a substantial bandwidth, high radiation efficiency, a reproducible design for easy manufacture and high power handling capability. There is further a need to control the radiation sidelobes for an array of such antennas.

Directional microstrip antenna with stacked planar elements


A draining laboratory drying rack system comprises a panel having a plurality of apertures formed therein, a plurality of pegs mounted in the apertures for supporting wet laboratory equipment, and a dispensing unit mounted to the panel by hooks on the dispensing unit being received within the apertures. The incorporation of the dispensing unit provides for mounting safety article dispensers within convenient reach of a user.

1. Field of the Invention
The invention relates to a draining laboratory drying rack system and, more specifically, to an improved draining laboratory drying rack system with a dispensing unit.
2. Description of the Related Art
In chemical laboratories, medical testing centers, and other facilities wherein glassware and other laboratory equipment is frequently used, drain boards or racks are utilized for holding the wet glassware and equipment to air dry after washing. U.S. Pat. No. 3,779,392, issued Dec. 18, 1973 to Betts, Sr.; U.S. Pat. No. 3,912,212, issued Oct. 14, 1975 to Betts, Sr.; U.S. Pat. No. 4,485,929, issued Dec. 4, 1984 to Betts, Sr.; and U.S. Pat. No. 5,163,567, issued Nov. 17, 1992 to Betts, Sr. disclose a lightweight laboratory drain board formed from sheet material with pegs extending from the board to support laboratory equipment thereon. The laboratory drain boards or panels can be wall mounted or freestanding. Pegs are selectively received in apertures of the board. In the Betts, Sr. '392 patent, the pegs are secured to the board by slip nuts. The pegs of the Betts, Sr. '212 and Betts, Sr. '929 patents are provided with an enlarged head having a smaller neck portion which is inserted through the aperture and subsequently slide downward into place to thereby lock the peg onto the drain board. In the Betts, Sr. '212 patent, T-shaped pegs are used in T-shaped apertures, and in the Betts, Sr. '929 patent, triangular-shaped pegs are mounted in triangular-shaped apertures. In the Betts, Sr. '567 patent, a catch drain is provided on the rear surface of the board to collect and remove any liquid that collects or seeps onto the rear surface of the board.
Laboratory draining rack systems, such as those disclosed in the various Betts, Sr. patents discussed above, are widely used in medical testing and research facilities. Several of these facilities are conducting research and tests on highly contagious and deadly viruses, such as the HIV virus which is the cause of Acquired Immune Disease Syndrome (AIDS). Not surprisingly, the laboratory workers exposed to such viruses on a daily basis are very safety conscious in their handling of the viruses and the cleaning the laboratory and laboratory equipment to prevent contamination or exposure. Given the repeated contact with highly contagious or deadly viruses, there is a need to provide the user of the draining rack system with a convenient dispenser for safety articles, such as gloves and masks, for example.

Laboratory drying rack system and a dispenser unit therefor


A method processes the outputs of a discrete sensor in a computer system. An initial value mask is applied to each one of the offset bits in the output of the discrete sensor. An initial value is obtained for each one of the offset bits in the output of the discrete sensor according to the initial value mask. It is next determined whether or not the offset bits in the output of the discrete sensor includes both initialization offset bits and transition offset bits. If the offset bits include both initialization offset bits and transition bits, only the initialization bits of an incoming mask corresponding to the output of the discrete sensor are reset.

1. Field of the Invention
This invention relates generally to computer systems. In particular, the present invention relates to methods of managing the discrete sensors in server computer systems.
2. Description of the Related Art
Many computer systems, such as servers, include system management having various management features. The system management is responsive to various sensors. These sensors may detect, for example, the absence/presence and the operation/failure of a power supply. The sensors may include xe2x80x9cthreshold sensorsxe2x80x9d which provide analog values such as voltage or temperature and xe2x80x9cdiscrete sensorsxe2x80x9d which are sensors of a digital type returning one or two bytes of data, each one of the bits in the data having a value changing between 0 and 1 to identify a sensor status or event occurrence. For example, there might be a plurality of processor status discrete sensors which return bits in response to a query of the sensor indicative of several different characteristics of the corresponding processor. For example, one of the returned bits could indicate whether or not the processor is present, another bit could indicate whether or not there""s been a thermal trip in the processor, another bit could indicate whether or not the processor slot is occupied by a terminator, and another bit could indicate whether or not there has been a booting error.
The data signals can be queried by system management or sent automatically by the sensor, for example, upon the occurrence of some specified event. Unfortunately, the algorithms in current system managements process the offsets at sensor level as a whole, instead of individual discrete offset level. This makes it difficult to handle the offsets efficiently and to easily adapt when changes are made to the hardware platform, and corresponding discrete sensors, in a computer system.

Management of sensors in computer systems