A method and several variants are provided for analyzing and transforming a computer program such that instructions may be reordered even across instructions that may throw an exception, while strictly preserving the precise exception semantics of the original program. The method uses program analysis to identify the subset of program state that needs to be preserved if an exception is thrown. Furthermore, the method performs a program transformation that allows dependence constraints among potentially excepting instructions to be completely ignored while applying program optimizations. This transformation does not require any special hardware support, and requires a compensation code to be executed only if an exception is thrown, i.e., no additional instructions need to be executed if an exception is not thrown. Variants of the method show how one or several of the features of the method may be performed.

The present invention generally relates to computer programming, and, in particular, to methods and apparatus for a compiler (either static or dynamic), programming development environment or tool, or programmer to enable transformations of a program that involve code motion across instructions that may throw an exception, while strictly preserving the precise exception semantics of the program or parts of the program that existed before the transformation.
The present invention describes methods and apparatus for a compiler, programming development environment or tool, or programmer to enable transformation of a program or parts of a program written in some machine language so as to eliminate or reduce the impact of precise exceptions on optimizations that require instruction reordering.
Some programming languages, for example, Java(trademark) (e.g., see J. Gosling, B. Joy, G. L. Steele, xe2x80x9cThe Java Language Specification (Java Series),xe2x80x9d Addison-Wesley Publishing Company, Reading, Mass. 1996), Ada, Modula-3, and C++ support exceptions, which represent abnormal execution conditions arising, for instance, out of violations of the semantic constraints of the language. We shall refer to an exception as being thrown or raised at a point where it occurs, and as being caught at the exception handler, which is the point to which control is transferred when the exception is thrown. The actual mechanism for determining where the control is transferred in case of an exception being thrown is part of the specification of a programming language. For example, Java(trademark) defines try-catch blocks that govern control flow when an exception is thrown by a statementxe2x80x94execution proceeds to the closest dynamically enclosing catch block that handles the exception. An exception may be thrown explicitly, such as via a throw statement in Java(trademark), or implicitly, based on checks defined by the programming language. For instance, Java(trademark) defines some runtime exceptions such as NullPointerException, IndexOutOfBoundsException, and ArithmeticException, and many instructions such as array-access instructions, object field-access instructions, and integer division instructions may throw one of the predefined runtime exceptions. We refer to an instruction that may throw an exception as a potentially excepting instruction (PEI in short).
In some languages, like Java(trademark), exceptions are defined to be precise, which implies that:
1) exception(s) must be thrown in the same order as specified by the original program; and
2) when an exception is thrown, the program state observable at the entry of the corresponding exception handler must be the same as in the original program.
Compilers often use a representation called the Dependence Graph to represent constraints on code motion and instruction reordering. The nodes in a dependence graph typically represent statements, and edges represent dependence constraints. Compilers for languages supporting precise exceptions satisfy the precise exception requirement by imposing the following dependence constraints, described further in J.-D. Choi, D. Grove, M. Hind, and V. Sarkar, xe2x80x9cEfficient and precise handling of exceptions for analysis of Java programs,xe2x80x9d ACM SIGPLAN-SIGSOFT Workshop on Program Analysis for Software Tools and Engineering, September 1999:
1) dependences among PEIs, referred to as exception-sequence dependences, which ensure that the correct exception is thrown by the code, and
2) dependences between writes to non-temporary variables and PEIs, referred to as write-barrier dependences, which ensure that a write to a non-temporary variable is not moved before or after a PEI, in order to maintain the correct program state if an exception is thrown. These dependences hamper a wide range of program optimizations in the presence of PEIs, such as instruction scheduling, instruction selection (across a PEI), loop transformations, and parallelization. This impedes the performance of programs written in languages like Java(trademark), in which PEIs are quite common.
A reference to a variable is said to be live at a program point if the value of the variable is used after that program point on some control flow path to the exit before it is redefined.
Let us use the Java code segment shown in FIG. 3 as an example. FIG. 4 shows the low-level intermediate representation (LIR) of the Java code in FIG. 3. Compilers frequently use LIR representation of the input program, similar to the LIR in FIG. 4, during the analysis and optimization of the program. FIG. 5 shows the dependence graph of the LIR in FIG. 4. Compilers frequently use dependence graphs, similar to FIG. 5, for analysis and optimization of programs. We define the dependence locus of a node Ni in the dependence graph to be the set of nodes that are transitively reachable from Ni via dependence edges. Each node in the dependence graph corresponds to a statement (i.e., line) in the LIR. The column titled Dependence Graph Node in the LIR shows the corresponding node in the dependence graph of the statement.
In the dependence graph in FIG. 5, exception-sequence dependences are shown as dashed lines, while write-barrier dependences are shown as dotted edges, such as from n9 to P10. The longest path of the graph shown in the figure has a length of 10: P1, P5, n6, P7, n8, n9, P10, n11, P12, n13, and n14.
A program with more than one thread (locus of control) is said to be multithreaded. In a multithreaded application, the shared program state when an exception is thrown can be visible not only to the exception handler, if any exists, of the exception-throwing thread, but also potentially to any other threads that can access the program state. Furthermore, an exception not caught by a handler terminates only the exception-throwing thread, and other threads can still access the shared program state affected by the terminating thread and continue their execution.
Allowing for uncontrolled accesses (read or write) to shared program state by multiple threads usually renders a program incorrect or, at best, hard to understand and develop. Most languages, therefore, provide mechanisms for controlling accesses to shared program state, i.e., shared variables. A synchronized region, such as a synchronized block or method in Java, is used in which to access a shared variable. Some languages go even further to specify that for a program to be correct, accesses to shared variables should be controlled xe2x80x9cproperly,xe2x80x9d usually implying that the program should obey the CREW protocolxe2x80x94Concurrent Read, Exclusive Write. In a CREW protocol, there can be as many concurrent read accesses as long as there is no concurrent write access, but no read or write accesses can be concurrent with another write access to the same variable. We refer to languages that force parallel programs to obey the CREW protocol or which do not specify any constraints on the ordering of data accesses in regions not obeying the CREW protocol, as languages supporting weak consistency. We refer to other languages, which do impose constraints on the ordering of data accesses even in regions not obeying the CREW protocol, as supporting strong consistency.
Many compilers use a representation called a call graph to analyze an entire program. A call graph has nodes representing procedures, and edges representing procedure calls. We use the term procedure to refer to subroutines, functions, and also methods in object-oriented languages. A direct procedure call, where the callee (called procedure) is known at the call site, is represented by a single edge in the call graph from the caller to the callee. A procedure call, where the callee is not known, such as a virtual-method call in an object-oriented language or an indirect call through a pointer, is represented by edges from the caller to each possible callee. It is also possible that given a particular (callee) procedure, all callers of it may not be known. In that case, the call graph would conservatively put edges from all possible callers to that callee.
A topological sort order enumeration of nodes in a graph refers to an enumeration in which, if the graph contains an edge from node x to node y, then x appears before y. If a graph has cycles, then such an enumeration is not guaranteed for nodes involved in a cycle. A reverse topological sort order lists nodes in the reverse order of a topological sort.
Prior art for a similar goal of allowing instruction reordering in the presence of exceptions can be found in the papers: D. August, D. Connors, S, Mahike, J. Sias, K. Crozier, B.-C. Cheng, P. Eaton, Q. Olaniran, and W.-M. Hwu, xe2x80x9cIntegrated predicated and speculative execution in the IMPACT EPIC architecture,xe2x80x9d Proceedings of 25th International Symposium on Computer Architecture, July 1998; P. Chang, S. Mahlke, W. Chen, N. Water, and W.-M. Hwu, xe2x80x9cIMPACT: An architectural framework for multiple-instruction-issue processors,xe2x80x9d Proceedings of 18th International Symposium on Computer Architecture, pages 266-275, 1991; K. Ebcioglu, xe2x80x9cSome design ideas for a VLIW architecture for sequential natured software,xe2x80x9d Parallel Processing, pages 3-21, M. Cosnard et al. (editors), North Holland, 1988; K. Ebcioglu and G. Silberman, xe2x80x9cAn architectural framework for supporting heterogeneous instruction-set architectures,xe2x80x9d IEEE Computer, 26(6), pages 39-56, June 1993; K. Ebcioglu and E. R. Altman, xe2x80x9cDAISY: Dynamic compilation for 100% architectural compatibility,xe2x80x9d Proceedings of 24th International Symposium on Computer Architecture, pages 26-37, Denver, Colo., June 1997; S. Mahlke, W. Chen, R. Bringmann, R. Hank, W.-M. Hwu, B. Rau, and M. Schlansker, xe2x80x9cSentinel scheduling: A model for compiler-controlled speculative execution,xe2x80x9d ACM Transactions on Computer Systems, 11(4):376-408, November 1993; M. Smith, M. Lam, and M. Horowitz, xe2x80x9cBoosting beyond static scheduling in a superscalar processor,xe2x80x9d Proceedings of 19th International Symposium on Computer Architecture, pages 344-354, May 1990; and in U.S. Pat. No. 5,799,179 to K. Ebcioglu and G. Silberman entitled xe2x80x9cHandling of exceptions in speculative instructions,xe2x80x9d issued on Aug. 25, 1998. These methods differ from the method described in this invention, at least, in that they require special hardware support to ensure that the results of speculatively executed instructions that raise an exception are not committed prematurely. Furthermore, these methods do not attempt to reduce the program state that must be preserved at a possible exception point.
Prior art for aggressive code motion of instructions, including PEIs, can be found in K. Ebcioglu, xe2x80x9cSome design ideas for a VLIW architecture for sequential natured software,xe2x80x9d Parallel Processing, pages 3-21, M. Cosnard et al. (editors), North Holland, 1988. The method presented in this Ebcioglu article has the drawback of requiring special hardware support for extra instruction opcodes to indicate a non-speculative or speculative version, and an extra bit in the registers to denote a xe2x80x9cbottomxe2x80x9d result from an instruction that causes an exception.
Prior art for aggressive code motion of instructions, including PEIs, can be found in M. Smith, M. Lam, and M. Horowitz, xe2x80x9cBoosting beyond static scheduling in a superscalar processor,xe2x80x9d Proceedings of 19th International Symposium on Computer Architecture, pages 344-354, May 1990. The method presented in this Smith et al. article has the drawback of requiring expensive hardware support in the form of shadow register files and shadow store buffers to hold the result of speculative instructions.
Prior art for aggressive code motion of instructions, including PEIs, can be found in P. Chang, S. Mahlke, W. Chen, N. Water, and W.-M. Hwu, xe2x80x9cIMPACT: An architectural framework for multiple-instruction-issue processors,xe2x80x9d Proceedings of 18th International Symposium on Computer Architecture, pages 266-275, 1991. The method presented in this Chang et al. article has two drawbacks: (i) it requires hardware support for silent exceptions, i.e., for ignoring exceptions thrown by speculatively executed instructions, and (ii) it may fail to throw an exception that is thrown by the original, unoptimized program, which would constitute a violation of program semantics in a language like Java(trademark).
Prior art for aggressive code motion of instructions, including PEIs, can be found in S. Mahlke, W. Chen, R. Bringmann, R. Hank, W.-M. Hwu, B. Rau, and M. Schlansker, xe2x80x9cSentinel scheduling: A model for compiler-controlled speculative execution,xe2x80x9d ACM Transactions on Computer Systems, 11(4):376-408, November 1993. This method also has the drawback of requiring special hardware support in the form of extra bit on registers to record whether a speculative instruction caused an exception, as well as an extra bit in the instruction opcode to distinguish between speculative and non-speculative instructions.
Prior art for aggressive code motion of instructions, including PEIs, can be found in K. Ebcioglu and G. Silberman, xe2x80x9cAn architectural framework for supporting heterogeneous instruction-set architectures,xe2x80x9d IEEE Computer, 26(6), pages 39-56, June 1993 and K. Ebcioglu and E. R. Altman, xe2x80x9cDAISY: Dynamic compilation for 100% architectural compatibility,xe2x80x9d Proceedings of 24th International Symposium on Computer Architecture, pages 26-37, Denver, Colo., June 1997. The methods presented in these Ebcioglu articles have the drawback of requiring special hardware support for non-architected registers to hold the results of operations executed out of order.
Prior art for aggressive code motion of instructions, including PEIs, can be found in U.S. Pat. No. 5,799,179 to K. Ebcioglu and G. Silberman entitled xe2x80x9cHandling of exceptions in speculative instructions,xe2x80x9d issued on Aug. 25, 1998. The method presented in this Ebcioglu et al. patent has the drawback of requiring special hardware support in the form of extra bits in registers for exception tracking and recovery.
Prior art for aggressive code motion of instructions, including PEIs, without requiring any special hardware support, can be found in B. C. Le, xe2x80x9cAn out-of-order execution technique for runtime binary translators,xe2x80x9d Proceedings of the 8th International Conference on Architectural Support for Programming Languages and Operating Systems, pages 151-158, October 1998. However, this method requires the generation of check-pointing code, which contributes to the overhead of executing extra instructions even when no exception is thrown. This overhead of check-pointing can potentially be high.
Prior art for aggressive program transformations in the presence of exceptions can be found in A. Aiken, J. W. Williams, and E. L. Wimmers, xe2x80x9cSafe: A semantic technique for transforming programs in the presence of errors,xe2x80x9d ACM Transactions on Programming Languages and Systems, 17(1):63-84, January 1995. This method defines a higher-order function called Safe, which is used to annotate parts of the program that are guaranteed not to produce errors or exceptions. This method is not applicable to many computations, where it cannot be guaranteed that exceptions will not take place, even if exceptions are rare.
Prior art for aggressive program transformations in the presence of exceptions can be found in U.S. Pat. No. 6,343,375, issued on Jan. 29, 2002 to M. Gupta, S. Midkiff, and J. Moreira, and entitled xe2x80x9cMethod for optimizing array bounds checks in programs.xe2x80x9d This method performs a program transformation to create safe regions in which no exception may take place. However, this method is only applicable to a restricted class of computations using arrays, and can only be used to handle out-of-bounds array index exceptions and null-pointer exceptions. For many computations, no such safe regions can be created using this method.
The present invention provides methods and apparatus to analyze and transform a computer program so as to enable program transformations which require code motion across potentially excepting instructions, while strictly preserving the precise exception semantics of the original program. Examples of program transformations that benefit from our method include instruction scheduling, instruction selection across a PEI, loop transformations to improve data locality and instruction-level parallelism, and program parallelization. Thus, the transformations enabled by this invention are important to improve the performance of the program being transformed, and also to decrease the execution time of other programs executing on the system.
In a first aspect of the invention, a method of optimizing a computer program written in a language that supports exceptions, comprises the steps of: (i) identifying in the computer program a statement that writes into a variable and a statement corresponding to a potentially excepting instruction; and (ii) removing a constraint on moving the write statement across the potentially excepting instruction when the variable written by the write statement is determined to be not live at an exception handler that catches the exception when thrown.
In a second aspect of the invention, a method of optimizing a computer program written in a language that supports exceptions, comprises the steps of: (i) transforming each code region to be optimized by performing optimizations without any constraints on ordering between potentially excepting instructions; and (ii) generating compensation code which executes only if an exception is thrown by the region transformed in the transforming step.
A preferred method of the present invention first performs a static analysis of the program to identify the types of exceptions possibly thrown in the program, and to determine the liveness of variables at entry to different exception handlers in the program. The method then performs two transformations on the program, which deal respectively with overcoming write-barrier dependences and exception sequence dependences involving PEIs.
The first transformation adds a parameter to each procedure being optimized, which encodes the information about liveness of variables at each dynamically enclosing exception handler for the given procedure call. This information is used at runtime to select one of two versions of the procedure generated by the compiler as follows. The first version is applicable when no variable written in the procedure, other than the implicit exception object, is live at any exception handler (dynamically enclosing the procedure call) which could catch an exception thrown during the procedure call; the second version is selected otherwise. The first version of the procedure, which we shall refer to as the specialized version, is optimized by the compiler while completely ignoring all write-barrier dependences involving PEIs in code regions inside it without any local exception handler. The program optimizations in the second version, which is the original procedure and is referred to as the normal version, remain constrained by the write-barrier dependences due to PEIs. Thus, in cases where the runtime information obtained using our method allows the specialized version of the procedure to be selected during execution, better performance can be obtained due to more effective optimizations.
For multithreaded programs, our preferred method performs the following additional analysis. If the programming language supports weak consistency and if the code region being optimized is part of a synchronized region, no further write-barrier dependences are imposed. However, if either the programming language supports strong consistency or if the code region is inside a synchronized region, our method performs analysis to detect thread-local variables. In this case, write-barrier dependences are honored between PEIs and writes of variables that are not thread-local.
The second transformation is performed, in a preferred method of the invention, on the specialized version of a procedure. This transformation further creates two regions out of the code region to which it is applied. The first region, called the optimized code, is obtained by allowing optimizations that completely ignore all exception-sequence dependences in the original region. The second region, called the compensation code, intercepts any exception thrown in the optimized region, and throws the correct exception that would have been thrown by the original, unoptimized code. This compensation code is executed only if and when an exception is thrown during the execution of the optimized code. Hence, in the common case where the execution of the program leads to no exception being thrown, this transformation allows the program to be optimized, completely ignoring all exception-sequence dependences, without the overhead of executing any part of the compensation code.
An alternative embodiment of the method uses a different analysis to overcome the write-barrier dependences due to PEIs. In this embodiment, no extra parameter is added to procedures. Instead, the analysis to record the liveness information of variables at enclosing exception is done at compile time, using the call graph representation of the program. The information about exception handlers, if any, surrounding a procedure call from A to B is propagated to B and to all procedures reachable in the call graph from B (representing all procedures transitively called from B). In this embodiment, there is no need to create a specialized version of the procedure. All write-barrier dependences related to PEIs that do not have a non-trivial enclosing exception handler, are ignored. In the special case where the static analysis shows that a procedure cannot have any dynamically enclosing exception handler with live variables, those regions of code in that procedure which do not have an exception handler block within the procedure, can be viewed as write-barrier-free regions. These regions are optimized while ignoring all write-barrier dependences.
Another alternative embodiment of the method performs the transformation to eliminate exception-sequence dependences on both the specialized version (without write-barrier dependences) and the normal version (with write-barrier dependences) of the procedure, in order to get the benefits of overcoming exception-sequence dependences regardless of the need to preserve the values of variables at potential exception points in the procedure.
Other embodiments of the method perform the analysis and transformations at run time, in a dynamic compiler. A variant of this embodiment does not create the compensation code, which ensures that the correct exception is thrown, during code generation time. It generates the compensation code only on demand, if an exception is thrown in the optimized code. Similarly, another variant of the method does not initially generate two versions of the procedure code in order to overcome the write-barrier dependences. It generates code for only the version (write-barrier-free or the original code) that will be executed, based on the expected information about liveness of variables at enclosing exception handlers for the given procedure call, and generates code for the other version on demand, if needed.
Another embodiment of the method computes and uses information about the set of live variables at entry to each exception handler at a finer granularity. This embodiment imposes write-barrier dependences for each PEI separately, based on information about the set of variables that are live at the exception handler(s) for the exception possibly thrown by that PEI.

Methods and apparatus for optimizing programs in the presence of exceptions

International Business Machines Corporation


An optical recording medium which can be recorded and read at a short wavelength (about 635-680 nm) or which can be recorded and read at two wavelengths, the short wavelength and a conventional wavelength (about 780 nm) has a recording layer containing an azo metal complex dye obtained by reacting a metal compound with an azo compound of formula (I) or an azo compound of formula (II). ##STR1## In formula (I), Q.sub.1 is a group of atoms necessary to form an aromatic ring with two C, A is C or a hetero-atom, Q.sub.2 is a group of atoms necessary to form an aromatic ring with two C and A, and Q.sub.3 is a group of atoms necessary to form an aromatic ring with C, N and A, fused to the aromatic ring completed by Q.sub.2. In formula (II), Q.sup.1 is a 8-quinolyl radical and Q.sup.2 is a 2-imidazolyl radical whose nitrogen at the 1-position has active hydrogen.

1. Field of the Invention
This invention relates to an optical recording medium using an azo metal complex dye in a recording layer.
2. Prior Art
The present inventors have been engaged in the development of write-once type compact discs (CD-R) as a recordable optical recording medium corresponding to the compact disc (CD) standard. Higher density optical recording media are desired in the recent years, and some of such media heretofore proposed are CD-R of the next generation wherein the recording wavelength of CD-R is reduced from the current 780 nm to 680 nm to 635 nm and write-once type digital video discs (DVD-R). However, since development works have hitherto been made so as to match with 780 nm, there are known few dyes which can satisfy desired characteristics including light resistance, solubility and recording sensitivity on the shorter wavelength side of 680 nm to 635 nm. A further noteworthy requirement is interchangeability with the current standard. More particularly, unless the media which have been recorded by the existing recording device are at least readable with shorter wavelength light, there results a barrier against simple and rapid utilization of a pile of past accumulated information. For short wavelength recording layers to be developed from now on, it is considered important that they not only satisfy the standard at the current standard for wavelength 780 nm, known as the Orange Book standard, but also exhibit equivalent characteristics to the current standard even at 680 nm to 635 nm.
One measure contemplated to realize this demand in a most practical way is by mixing a dye for a short wavelength with a proper amount of a dye having satisfactory characteristics on the current standard, but free of substantial absorbance on the short wavelength side so as to satisfy characteristics at both the wavelengths. In this case, recording characteristics of a mixed system must be fully investigated.
For a dye to be used in recording layers, one characteristic which is especially important and difficult to accomplish is light resistance although the recording wavelength is important. Heretofore, dyes belonging to metal complex systems have been disclosed as highly light resistant dyes. As disclosed in JP-A 55795/1984, for example, there is known an example of combining a cyanine dye having low light resistance with a metal complex quencher for improving light resistance. This system, however, has the drawbacks that it has a drastically reduced solubility in a coating solvent used for spin coating and that the stabilizer itself can be decomposed and degraded. Other dyes having high light resistance include, for example, azo metal complex dyes (JP-B 51682/1995) and formazane nickel complex dyes (JP-A 254038/1985 and 144997/1987). Although these metal complex dyes surely have excellent light resistance, they generally have drawbacks of low recording sensitivity, relatively low solubility, and solubility in only limited solvents. When write/read operation at a short wavelength of 680 nm to 635 nm is taken into account, the formazane nickel complex dyes have a too long absorption wavelength, suggesting that this skeleton can no longer accommodate shorter wavelengths.
With respect to the phthalocyanine dyes known as highly light resistant dyes from the past, they are also difficult to avoid the above-mentioned drawbacks and thus deemed impossible to expect further development as a dye appropriated for short wavelength recording layers. As mentioned above, there is a strong demand for a dye skeleton which possesses desired write/read characteristics at a short wavelength of 680 nm to 635 nm, especially when used in a mixed system with a dye having absorbance on the long wavelength side, and which has high light resistance and solubility by itself.


A die for the preparation of a toner resin in an extruder having a housing defining a housing aperture therein and a conveyor for conveying the resin through the housing aperture to form a stream of resin is provided. The die includes a member connected to a first end of the housing. The member defines an opening therethrough. The cross sectional area of the opening is progressively reduced in the direction of the stream of resin for at least a substantial portion of the opening.

1. Field of the Invention
The present invention relates to a method and apparatus for manufacturing resins and resin compounds. More particularly, the invention relates to an apparatus and method for extruding resins and resin compounds through a die.
2. Description of the Prior Art
In the process of electrophotographic printing, a photoconductive surface has an electrostatic latent image recorded therein. Toner particles are attracted from carrier granules to the latent image to develop the latent image. Thereafter, the toner image is transferred from the photoconductive surface to a sheet and fused thereto.
Typically, toner may be produced by melt-mixing the polymer and pigment whereby the pigment is dispersed in the polymer. The polymer having the colorant dispersed therein is then pulverized. Recently in U.S. Pat. No. 5,227,460 (Mahabadi et al.), incorporated herein by reference, a low melt toner resin with minimum fix temperature and wide fusing latitude containing a linear portion and a cross-linked portion containing high density cross-linked microgel particles, but substantially no low density cross linked polymer was disclosed. A method of manufacturing that toner and its resin was disclosed in U.S. Pat. No. 5,376,494 (Mahabadi et al.), incorporated herein by reference. The method of fabricating the low fix temperature toner resins includes a reactive melt mixing process wherein polymer resins are cross-linked at high temperature and high shear. The resins are particularly suitable for high speed fusing, show excellent offset resistance and wide fusing latitude and superior vinyl offset properties.
The polymer and pigment are melt mixed together typically in an extruder which is part of an extruding system. The polymer and pigment are translated and mixed in an auger within a cavity of the extruder. A die plate is located on the exit end of the extruder. A conventional die plate has round holes to enable the extrusion of high viscosity materials and subsequent processing which includes thinning , cooling and crushing. A conventional strand die plate with small holes would be prone to plugging and would generate extremely high back pressure. This would result in vacuum vent flow and other processing problems that create considerable down time to the extruding machine.
Often, the die plate has to be removed from the extruder for off-line cleaning, which is a length and labor intensive activity. To avoid the plugging and time consuming off-line cleaning associated with the die plates with small holes, die plates with much larger holes have been used.
When large holes are used for the die plate, a large slab of high viscosity extrudate exits from the extruder. This extrudate must be squeezed and spread by nip rolls. This large high viscosity slab often slips when entering the nip rolls. Subsequent processing of this cross sectional slab is very difficult. The slab is typically much thinner at the outer edges of the slab making the processing even more difficult
The following disclosures may be relevant to various aspects of the present invention:


According to one embodiment, an adjusting element adjusts a dynamic flying height of a head lying over a disk in accordance with the power supplied to it. A calculation module calculates the power to supply to the adjusting element, from a barometric pressure detected by a barometric pressure sensor. A failure detection module detects failure of the barometric pressure sensor. An unload controller predicts an abnormal dynamic flying height of the head from the failure detected and then instructs the unloading of the head away from the disk.

1. Field
One embodiment of the invention relates to a disk drive in which the dynamic flying height of the head can be adjusted by supplying to the head the power calculated from the barometric pressure detected by, for example, a barometric pressure sensor.
2. Description of the Related Art
Disk drives (e.g., magnetic disk drives) having an actuator that can adjust the dynamic flying height (DFH) of the head have been hitherto known. The actuator has a slider (magnetic head slider) that holds the head (magnetic head). The actuator supports the slider and can move the slider radially over the disk (magnetic disk). As generally defined, the dynamic flying height of the head is the distance between the head and the disk (more precisely, the surface of the disk, i.e., disk surface).
Known as actuators capable of adjusting the dynamic flying height of the head are thermal actuators, piezoelectric actuators, and the like. Such an actuator can adjust the dynamic flying height of the head as its part is deformed. The thermal actuator, for example, has its slider deformed through thermal expansion. Used as a heat source (adjusting element) that achieves the thermal expansion is a heater (resistive heating element). The heater is arranged at that part of the slider which lies near the head. In the thermal actuator, the power supplied to the heater is controlled, varying the thermal expansion of the slider (head). The dynamic flying height of the head is thereby adjusted. As described in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-014092, the dynamic flying height of the head is measured (or estimated) from the harmonic wave ratio of a signal reproduced by the head.
The piezoelectric actuator has a slider, a suspension and a piezoelectric element. The suspension supports the slider. The piezoelectric element is arranged on the slider (or on the suspension). A voltage is applied to the piezoelectric element, adjusting the deformation of the slider. The dynamic flying height of the head is thereby adjusted. That is, the piezoelectric actuator uses a piezoelectric element as an element (adjusting element) for adjusting the dynamic flying height of the head.
The dynamic flying height of the head changes with the barometric pressure (ambient barometric pressure) in the environment where the disk drive is used, as is described in, for example, Jpn. Pat. Appln. Publication No. 09-063220, Jpn. Pat. Appln. Publication No. 06-150522, Jpn. Pat. Appln. Publication No. 10-334626 and Jpn. Pat. Appln. Publication No. 2007-310957. More precisely, the higher the ambient barometric pressure, the higher the dynamic flying height of the head will be. Conversely, the lower the ambient barometric pressure, the lower the dynamic flying height of the head will be. In this way, if the dynamic flying height of the head changes in response to a change in the ambient barometric pressure, the head may not be able to stably write or read data with reference to a disk.
In view of this, such a technique (prior art)s disclosed in, for example, Jpn. Pat. Appln. Publication No. 09-063220 is used to maintain the dynamic flying height of the head always at a target value, not influenced by the ambient barometric pressure. In this prior art, a barometric pressure sensor measures the pressure ambient to the disk drive, and the power (i.e., voltage or current) supplied to the adjusting element of the actuator is controlled in accordance with the pressure thus measured. The dynamic flying height of the head can therefore be maintained at the target value.
With the prior art described above, however, the dynamic flying height of the head can hardly be maintained at the target value if the barometric pressure sensor fails to operate well. In particular, if the barometric pressure detected by the barometric pressure sensor is higher than the actual value, the head may be set at a dynamic flying height much smaller than the target value, as will be explained below.
If the barometric pressure detected by the barometric pressure sensor is higher than the actual value, the dynamic flying height of the head will be estimated greater than the target value. In this case, the power supplied to the adjusting element is increased over the value of the correct power that should be supplied to the adjusting element. Although the actual barometric pressure is lower than the pressure detected by the barometric pressure sensor, more power than necessary is supplied to the adjusting element. Therefore, the actual dynamic flying height of the head may be unusually set at a very low value compared to the target dynamic flying height. If the head has such a low dynamic flying height, it may contact the disk (disk medium) spinning at high speed. Consequently, the head may fail to function, or the disk (medium) may be damaged.

Disk drive in which the dynamic flying height of head is adjusted


A method of operating a four stroke, spark ignition, high compression ratio, internal combustion engine including at least one intake valve (30), exhaust valve (32) and charging valve (36) per cylinder (16). Each of the valves is actuable by a variable timing mechanism (50), which is controlled by an on-board computer (82) that varies the timing of valve opening and closing depending upon engine operating conditions. Each charging valve port (34) leads to an auxiliary chamber (40) having geometry to cause a swirling motion of the charge entering the chamber and surrounded by a cooling jacket (42) to cool the charge as it swirls before being released back into the cylinder during the next engine cycle.

Conventional spark ignition, four stroke, internal combustion engines generally operate with intake and exhaust valves in each cylinder actuated with a fixed timing relative to an engine crankshaft, and with a throttle valve upstream of the intake valves to control the engine load by throttling the air flow. Further, the compression ratio of each cylinder is fixed regardless of engine speed. This basic configuration, consequently, has drawbacks that limit the efficiency of the engine for most operating conditions, which others have tried to overcome.
One drawback is that the load is controlled by throttling the air past the throttle valve in order to operate at other than full load conditions. This, along with other restrictions of the air flow, creates pumping losses in the engine. One attempt to overcome the pumping losses is to provide for variably actuated intake and exhaust valves that allow for control of the intake flow, and hence load control, by varying the opening and closing of the valves rather than employing a throttle valve. This does reduce the pumping losses and gives greater control of engine operation over a wider range of engine operating conditions. However, this solution is limited by the fact that controlling the intake of the air/fuel mixture at low load and idle conditions will substantially reduce the compression ratio at those conditions, resulting in poor combustion characteristics for these load conditions. One solution, then, is to increase the compression ratio for each cylinder in the engine at low load conditions. One such attempt has been to provide a variable compression ratio assembly where adjustments are made to the piston travel or the cylinder volume to allow for an overall higher compression ratio, while at high loads reducing the compression ratio to avoid knock. These solutions, however, add great cost and complexity to the overall engine. Further, One of the main disadvantages of spark ignition engines relative to other known engines, such as diesel, are their inability to operate with a high compression ratio. Generally, spark ignition engines (Otto cycle engines) with higher compression ratios are more efficient, thus improving fuel economy. To prevent knock in a spark ignition engine, its compression ratio must be restricted to much lower values than those used in other engines such as diesels, and this is an important factor contributing to its lower fuel efficiency relative to diesel. Thus, by permitting the spark ignition engine to operate with a high compression ratio without knock, it can substantially increase the engine efficiency.
Generally, then, a fixed compression ratio is the economical way to design an engine. For an engine, nonetheless, the compression ratio has to be held below an upper limit at heavy load conditions to prevent knocking. Consequently, it operates at this low compression ratio condition even for low and medium load conditions where knocking is not a concern and a higher compression ratio would operate more efficiently. Further, this limits the ability to operate without throttling the air flow.
The reason for the knock at full-load conditions is that the amount of combustion generated heat is great, which in turn, leads to an excessive temperature of the unburned gas fraction in the cylinder and hence the onset of knock. This puts a limit on the total amount of heat that can be transferred to the cylinder charge at a given engine speed during compression and combustion. At part-load, when the amount of combustion heat is relatively small, the engine could run knock-free with high compression ratio.
A further attempt to overcome the obstacles to maximizing engine efficiency relates to the flow characteristics for the air/fuel entering the cylinder. Less than ideal fluid flow and mixing will result in less than complete combustion, slow flame speed and burn rate, or both. Turbulence has been recognized as a primary driving force for good combustion in spark ignition engines. The practical and effective ways to increase turbulence production during combustion processes have been through the swirl- and tumble-generation devices. Split (dual) intake ports is an example of swirl-generating devices and tumble port used in four-valve engines is an example of tumble-generating device. Some have attempted to improve the flow characteristics by the geometry of the intake ports, employing vanes, or masking in order to improve mixing and create a swirl or tumble flow within the cylinder. However, these types of arrangements generally create flow restrictions, thus restricting and consequently limiting the maximum amount of flow into the cylinder and thus limiting the maximum engine output. Further, they are expensive to develop and produce. Thus, an inexpensive and reliable means for creating turbulence is desired that does not create flow restrictions.
Attempts have been made to overcome some of the above noted obstacles to maximum engine efficiency, but none satisfactorily improves most or all of these limitations of the conventional four stroke, spark ignition engine.

Method of generating turbulence with intra-cycle cooling for spark ignition engines


Method and apparatus for supporting interrupt devices configured for a specific architecture (e.g., APIC-based software and hardware) on a different platform (e.g., a PowerPC platform). One embodiment provides an apparatus for passing interrupts from one or more devices configured for a specific interrupt architecture to one or more processors not designed for the specific interrupt architecture, comprising: an abstraction layer comprising a first plurality of registers conforming to the specific interrupt architecture; and an implementation dependent layer, disposed in communication between the abstraction layer and the one or more processors, comprising a second plurality of registers which correspond to the first plurality of registers, wherein the implementation dependent layer is configured to receive interrupts and forward received interrupts to the one or more processors and to read and write data to the second plurality of registers in response to interrupts processed through the one or more processor.

1. Field of the Invention
The present invention generally relates to an interrupt controller for a processor, and more particularly, to an interrupt controller for supporting devices and software configured for a specific interrupt architecture on a processor which is not designed for the specific interrupt architecture.
2. Description of the Related Art
Generally, an interrupt is a signal from a device or a program that causes a processor to stop and determine the next operation to be performed. A processor is typically configured to handle hardware interrupts as well as software interrupts. A hardware interrupt occurs when a hardware device requires a processor to perform a particular operation, for example, when an input/output (I/O) operation is completed, such as reading data from a hard drive. A software interrupt occurs when an application program terminates or requests certain services from the processor.
Several methods are currently being used to pass interrupts (or exceptions) from a given source to a processor or multi-processor bus structure. One typical system used in both personal computing as well as multiprocessor server applications is described by the Advanced Programmable Interrupt Controller (APIC) architecture. In many typical multi-processor computer systems, the APIC interrupt delivery system is used to detect interrupt requests from attached peripheral devices and advise one or more processors to perform the requested services.
FIG. 1 is a block diagram illustrating a multi-processor environment 100 incorporating a conventional APIC architecture. Generally, the multi-processor environment 100 includes a plurality of processors 1101 to 110n having local APICs 1201 to 120n, respectively, an APIC bus 130 and an Input/Output Advanced Programmable Interrupt Controller (IOAPIC) 140. The local APICs 1201 to 120n on the processors 1101 to 110n are coupled to the IOAPIC 140 through the APIC bus 130. The IOAPIC 140 includes a set of interrupt signal inputs 150, an interrupt redirection table, programmable registers, and a messaging unit for sending and receiving APIC messages over the APIC bus 130. The IOAPIC 140 may be situated in an input/output subsystem and configured to receive interrupt requests 160 from peripheral devices. Upon detecting an interrupt request, the IOAPIC 140 transmits an APIC interrupt message which includes an interrupt vector providing information about the interrupt through the APIC bus 130 to the local APICs 1201 to 120n. Each of the local APICs 1201 to 120n is configured to determine whether an interrupt broadcast on the APIC bus 130 should be accepted. The local APICs 1201 to 120n handle all interactions between the respective processors 1101 to 110n and the IOAPIC 140.
Because of the popularity of the APIC architecture, various operating system kernel routines, hardware device drivers, and other hardware and software support are readily available utilizing this interrupt scheme. However, the APIC architecture is only compatible with particular processor platforms, such as the Intel® Architecture IA-32 processors, and is not readily reusable in other platforms, such as a PowerPC® processor platform. Thus, various operating system kernel routines, hardware device drivers and other hardware and software support that are based on the APIC architecture are not compatible with systems based on PowerPC platforms.
Therefore, there exists a need for an apparatus and method for supporting APIC-based software and hardware on a PowerPC platform. Particularly, there is a need for an interface system which can communicate interrupts of APIC-based hardware and software to PowerPC processor cores and return, after processing the interrupts, APIC-based information to the APIC-based hardware and software.

Method and apparatus for supporting interrupt devices configured for a particular architecture on a different platform

International Business Machines Corporation


The invention relates to oral care products such as toothpastes with an improved sensorially-perceivable cleaning benefit. This is achieved by the inclusion in the oral care products of agglomerates, substantially free from organic and/or inorganic binding agents, whereby the agglomerates are made of at least two, chemically and/or physically different particulate materials of specified particle sizes. The inclusion of materials having a therapeutic benefit on the teeth or gums in the agglomerates such as zinc citrate provides for a further benefit in that this material is slowly released from the agglomerates, thus providing for a delivery of this material over a longer period. Upon use, the gritty-feeling agglomerates will break-down into smaller particles, thus giving the consumer the feeling of initial cleaning and subsequent polishing.

1. Field of the Invention
The present invention relates to oral compositions for use in the human mouth. More particularly, it relates to oral compositions which contain agglomerates of particulate materials, which agglomerates impart a sensory benefit to the oral compositions which is perceivable upon use of the oral compositions.
The present invention especially relates to oral compositions which contain agglomerated particulate materials which contain at least a particulate dental abrasive cleaning agent, imparting to the oral composition a sensorially-perceivable cleaning benefit.
2. The Related Art
Oral compositions of the above type have already been proposed in the art. Thus, in EP-A-269,966, EP-A-473,171 and GB-A-2,252,042 oral compositions have been described which contain granules which are made from particulate dental abrasive cleaning agents which have been agglomerated with the aid of organic or inorganic binding agents. Upon use of such oral compositions in the mouth, the consumer perceives the presence of these granules, giving him the sensorial perception of a cleaning efficacy, and during brushing of the teeth with these oral compositions the granules are "crushed" by the pressure of the brush, whereby they fall apart into smaller particles which deliver a polishing effect, which the consumer sensorially perceives by a smooth feel of the oral composition and of the teeth. Typical examples of such granules are made of zeolite and colloidal silica, and magnesium alumino metasilicate as the binding agent or ethylcellulose as the binding agent.
In GB-A-2,272,640 oral compositions are described with abrasive particles which are friable under conditions of use of the composition. These particles are made from a particulate dental abrasive cleaning agent such as silica, which is agglomerated without the aid of an inorganic or organic water-insoluble binding agent, but rather by treatment with water and subsequent drying.
Although these prior proposals may lead to oral compositions that can deliver a certain sensory benefit, such benefit is not quite pronounced in several aspects. Furthermore, where mixtures of different materials are agglomerated, this requires the use of an organic or inorganic binding agent, which makes the manufacture of these agglomerates more expensive.


A switching power supply unit for providing an output voltage that is controlled such that a first detection voltage detected on the basis of the output voltage becomes equal to a first reference voltage. The peak voltage at the node of a serially connected coil and a switch of the switching power supply unit is detected and used as a second detection voltage for over-voltage protection. Thus, over-voltage protection of the switching power supply unit is secured with no additional terminal on the switching control IC for over-voltage protection even if such components as a feedback circuit and a rectifying diode of the power supply unit become open.

There have been widely used switching power supply units having a coil and a switching element for stepping up an input voltage to a predetermined high output voltage.
Such switching power supply unit has a voltage detection circuit for feeding back the output voltage as a feedback voltage to be compared with a reference voltage. Based on the comparison, the duty ratio and the frequency of the switching element are controlled so as to regulate the output voltage to a desired level. As a backup of the voltage control, the switching power supply unit is provided with an over-voltage protection circuit utilizing the voltage detection circuit to monitor the output voltage such that, should the detected voltage exceeds a predetermined allowable limit, the over-voltage protection circuit execute a protective measure (see for example, Japanese Patent Publication of Examined Application No. H7-50983).
However, such conventional switching power supply unit has a drawback in that the feed back voltage falls to zero when the voltage detection circuit suffers an open-circuit malfunction for some reason, feeding back no voltage. Then a switching-control circuit controlling the switching of the power supply unit makes a determination that the output voltage is insufficient, and acts to raise the output voltage. As a consequence, the output voltage rises towards the maximum allowable level of the switching power supply unit.
Although the output voltage is monitored, such run away of the output voltage happens because the voltage detection circuit for feedback control of the output voltage cannot detect an over-voltage caused by such open-circuit malfunction of the voltage detection circuit.
To circumvent this drawback, an additional voltage detection circuit for detecting an over-voltage may be provided in addition to the voltage detection circuit for feeding back the output voltage. In this case, however, it is necessary to provide an additional terminal for the additional circuit on the control IC for controlling the switching of the power supply unit (the IC referred to as switching control IC). Provision of such additional terminal, however, entails a disadvantage that the switching control IC cannot be fully miniaturized.
A further disadvantage is that an over-voltage condition due to an open-circuit malfunction of a constituent element of the switching power supply unit or breaking of a wire in the unit cannot be detected by a conventional over-voltage detection circuit. Therefore, in that event also the over-voltage can be impressed on various components of the power supply unit, including the switches of the switching control IC and other components.

Switching power supply unit and electronic apparatus having display


Uses of a dual V region antibody-like protein or a fragment of a dual V region antibody-like region.

Interleukin-4 (IL-4) is a pleiotropic cytokine that has a broad spectrum of biological effects on lymphoid B and T cells, and many non-lymphoid cells including monocytes, endothelial cells and fibroblasts. For example, IL-4 stimulates the proliferation of several IL-2- and IL-3-dependent cell lines, induces the expression of class II major histocompatability complex molecules on resting B cells, and enhances the secretion of IgG4 and IgE by human B cells. IL-4 is associated with a Th2-type immune response, and is produced by and promotes differentiation of Th2 cells. IL-4 has been implicated in a number of disorders, such as allergy and asthma.
IL-13 is a recently identified (Minty, A. et al., Nature, 1993, 362, 248-250, and McKenzie, A. N. et al., Proc. Natl. Acad. Sci. U.S.A, 1993, 90, 3735-3739) cytokine of 112 amino acids secreted by the activated T lymphocytes, the B lymphocytes and the mastocytes after activation. By virtue of its numerous biological properties shared with IL-4, IL-13 has been described as an IL-4-like cytokine. Its activities are indeed similar to those of IL-4 on the B cells (Defrance, T. et al., J. Exp. Med., 1994, 179, 135-143, Punnonen, J. et al., Proc. Natl. Acad. Sci. (USA), 1993, 90, 3730-3734, Fior, R. et al., Eur. Cytokine Network, 1994, 5, 593-600), the monocytes (Muzio, M. R. F. et al., Blood, 1994, 83, 1738-1743, De Waal Malefyt, R. et al., J. Immunol, 1993, 151, 6370-6381, Doyle, A. et al., Eur. J. Immunol. 1994, 24, 1441-1445, Montaner, L. J. et al., J. Exp. Med., 1993, 178, 743-747, Sozzani, P. et al., J. Biol. Chem., 1995, 270, 5084-5088) and other non-haematopoietic cells (Herbert, J. M. et al., Febs Lett., 1993, 328, 268-270, and Derocq, J. M. et al., Febs Lett. 1994, 343, 32-36). On the other hand, contrary to IL-4, it does not exert a specific effect on resting or activated T cells (Zurawuki, G. et al., Immunol. Today, 1994, 15, 19-26).
Various biological activities of IL-13 on the monocytes/macrophages, the B lymphocytes and certain haematopoietic precursors have been described in detail by A. J. Minty as well as in review articles on IL-13. Several data indicate, in addition, that this cytokine has a pleiotropic effect on other cell types. These non-haematopoietic cells which are directly affected by IL-13 are endothelial and microglial cells, keratinocytes and kidney and colon carcinomas.
One of the stages in the analysis of the signal transmitted by a biological molecule within a cell consists in identifying its membrane receptor. The research studies carried out to this end on the IL-13 receptor have shown that IL-13 and IL-4 have a common receptor, or at the very least some of the components of a common receptor complex, as well as common signal transduction elements (Zurawski S. M. et al., Embo Journal, 1993, 12, 2663-2670, Aversa, G. et al., J. Exp. Med., 1993, 178, 2213-2218, Vita, N. et al., Biol. Chem., 1995, 270, 3512-3517, Lefort, S. et al., Febs Lett., 1995, 366, 122-126). This receptor is present at the surface of various cell types, in a variable number according to the cell type considered. The comparative distribution of the IL-13 and IL-4 receptors has been indicated by A. J. Minty (Interleukin-13 for Cytokines in Health and Disease. Eds D. G. Remick and J. S. Frie, Marcel Decker, N.Y. 1996).
The cell surface receptors and receptor complexes bind IL-4 and/or IL-13 with different affinities. The principle components of receptors and receptor complexes that bind IL-4 and/or IL-13 are IL-4Rα, IL-13Rα1 and IL-13Rα2. These chains are expressed on the surface of cells as monomers or heterodimers of IL-4Rα/IL-13Rα1 (Type II IL-4R) or IL-4Rα/c (Type I IL-4R). IL-4Rα monomer and IL-4R/c heterodimer bind IL-4, but not IL-13. IL-13Rα1 and IL-13Rα2 monomers bind IL-13, but do not bind IL-4. IL-4Rα/IL-13Rα1 heterodimer binds both IL-4 and IL-13 (Murata et al., Int. J. Hematol., 1999, 69, 13-20).
Th2-type immune responses promote antibody production and humoral immunity, and are elaborated to fight off extracellular pathogens. Th2 cells are mediators of Ig production (humoral immunity) and produce IL-4, IL-5, IL-6, IL-9, IL-10 and IL-13 (Tanaka, et, al., Cytokine Regulation of Humoral Immunity, 251-272, Snapper, ed., John Wiley and Sons, New York (1996)). Th2-type immune responses are characterized by the generation of certain cytokines (e.g., IL-4, IL-13) and specific types of antibodies (IgE, IgG4) and are typical of allergic reactions, which may result in watery eyes and asthmatic symptoms, such as airway inflammation and contraction of airway muscle cells in the lungs.
Both IL-4 and IL-13 are therapeutically important cytokines based on their biological functions and play critical roles in many diseases, including asthma (Curr Opin Allergy Clin Immunol 2005, Vo. 5, 161-166). IL-4 has been shown to be able to inhibit autoimmune disease and IL-4 and IL-13 have both shown the potential to enhance anti-tumor immune responses. Elevations in IL-4 and IL-13 and their receptors have been linked to the pathogenesis of idiopathic pulmonary fibrosis (IPF) (Jakubzick C. et al., Am J Pathol. 2004:164(6):1989-2001; Murray L A et al. Int J Biochem Cell Biol. 2008:40(10):2174-82. Evidence in the literature demonstrate that the TH2 cytokines IL-4 and IL-13 play multiple roles in the pathogenesis of IPF as mediators of this lung tissue remodeling and fibrosis. Although the Th2-type CD4+ t cells in the lung are likely the predominant sources of IL-4 and IL-13, and are implicated as important regulators of extracellular matrix remodeling (Wynn, T A, Naat. Rev. Immunol, 4:583-594, 2004), other cell types including mast cells, basophils, eosinophils, macrophages and epithelial cells may also be potential sources of these cytokines (Gordon S and Martinez F O, Immunity Rev. 32:593-604, 2010). In IPF patients, IL-13 and IL-4 levels in bronchial alveolar lavage fluid are elevated compared to normal controls. Such evidence suggests that therapies capable of suppressing or neutralizing these cytokines have the potential for delaying the progression of fibrosis in IPF patients. Since both cytokines are involved in the pathogenesis of allergic diseases or fibrotic diseases, inhibitors of these cytokines could provide therapeutic benefits.
Accordingly, a need exists for improved agents that inhibit IL-4, inhibit IL-13, and single agents that inhibit both IL-4 and IL-13 that are non-immunogenic and safe for use in humans. We previously reported on a dual V region antibody like binding peptide having four binding sites that specifically bind to IL-4 and IL-13 (WO2009/052081 (PCT/US2008/079787), which is incorporated by reference in its entirety.


A method for manufacturing a spark plug includes: a preparation step of preparing a specimen provided with a center electrode, an insulator, a metal shell, and a ground electrode; and an inspection step of applying a predetermined voltage between the ground electrode and the center electrode of the prepared specimen, and determining whether dielectric breakdown is caused in the insulator. The inspection step includes a calculation step and a judgment step. The calculation step involves receiving an oscillating wave generated from the specimen upon application of the predetermined voltage to the specimen, obtaining a power spectrum by subjecting an oscillating wave signal representing the oscillating wave to fast Fourier transform, and then calculating an integral of a predetermined frequency range in the power spectrum. In the judgment step, whether discharge is caused by dielectric breakdown of the insulator is judged by utilizing the integral.

Conventionally, a spark plug is used for igniting an internal combustion engine, such as a gasoline engine (see, for example, Japanese Patent No. 4625531). The spark plug includes a center electrode, an insulator disposed on the outer periphery of the center electrode, a metal shell disposed on the outer periphery of the insulator, and a ground electrode attached to the metal shell and forming a spark gap with the center electrode.
An inspection method for determining whether there is damage in a structural body using an acoustic emission method (which may be hereafter referred to as an "AE method") is also known (see, for example, Japanese Patent No, 4811932).


A nitride semiconductor substrate having properties preferable for the manufacture of various nitride semiconductor devices is made available, by specifying or controlling the local variation in the off-axis angle of the principal surface of the nitride semiconductor substrate. In a nitride semiconductor single-crystal wafer having a flat principal surface, the crystallographic plane orientation of the principal surface of the nitride semiconductor single-crystal wafer varies locally within a predetermined angular range.

1. Technical Field
The present invention relates generally to nitride semiconductor substrates (wafers), and in particular to nitride semiconductor substrates that are especially utilizable in the manufacture of such components as light-emitting elements, electronic devices, semiconductor sensors, and surface acoustic wave devices.
2. Description of the Related Art
Components that in recent years are being manufactured using nitride semiconductors include: light-emitting elements such as light-emitting diodes and laser diodes; electronic devices such as rectifiers, bipolar transistors, field-effect transistors, and HEMTs (high electron mobility transistors); semiconductor sensors such as temperature sensors, pressure sensors, radiation sensors, and visible/ultraviolet light detectors; and SAW (surface acoustic wave) devices.
As represented in the schematic cross-sectional view of FIG. 3, such nitride semiconductors are manufactured using an epitaxial nitride semiconductor layer 2 (which in some cases includes multiple layers) having favorable crystalline properties that is grown epitaxially on the principal surface 1S of a nitride semiconductor substrate 1.
Japanese Unexamined Pat. App. Pub. No. 2003-527296 discloses an AlxGayIn1−(x+y)N (0≦x≦1, 0≦y≦1,x+y≦1) substrate having a flat principal surface, and states that it is preferable for the plane of the principal surface to have an off-axis angle inclined at an angle in a range of 1 to 10° from a crystallographic {0001} plane, {11 20} plane, {10 10} plane, or {10 12} plane.
For example, as illustrated by the schematic cross-sectional view of FIG. 2, when the principal surface 1S of the nitride semiconductor substrate 1 is inclined an angle θfrom a low-Miller-index plane CS (for example, a {0001} plane) of that nitride semiconductor crystal, such a substrate is referred to as a misoriented substrate. A substrate that has an off-axis angle of 0° may be referred to as an exact substrate.
Also, Japanese Unexamined Pat. App. Pub. No. 2004-502298 discloses an AlxGayIn1−(x+y)N (0≦x≦1, 0≦y≦1,x+y≦1) substrate having a flat principal surface, and states that it is preferable for the plane of the principal surface to have an off-axis angle inclined at an angle in a range of 0.1 to 10° from a crystallographic {0001} plane.
In order to manufacture a favorable semiconductor device by epitaxially growing a flat and thin nitride semiconductor layer on a nitride semiconductor substrate, it is preferable to use a flat substrate face having a crystallographic low-Miller-index plane (θ=0°) or a predetermined off-axis angle (θ≠0°) relative to that plane.
However, a problem with such nitride semiconductor substrates is that from region to region locally along the substrate principal surface, characteristics such as optical, electrical, and mechanical properties are inadequate or variations occur.
Also, finding the optimum substrate misorientation angle for epitaxially growing a nitride semiconductor layer onto a nitride semiconductor substrate face to manufacture a favorable semiconductor device is not a simple matter.
The reason for this difficulty is that, as illustrated in the schematic cross-sectional view in FIG. 1, without local variation Δθ in the off-axis angle θ of the principal surface 1S of the nitride semiconductor substrate 1 being set down or controlled, variation Δθ in the off-axis angle will differ from substrate to substrate, or the value of Δθ will be insufficient (<0.05°) to make the determination as to optimum misorientation angle.


A method for controlling etching during photolithography in the fabrication of an integrated circuit in connection with first and second features that are formed on the integrated circuit having a gap there between comprising depositing a layer of photoresist on the integrated circuit, selectively exposing portions of the photoresist through at least one photolithography mask having a pattern including means for alleviating line end shortening of the first and second lines adjacent the gap, and developing the photoresist after the selective exposing step.

The invention pertains to semiconductor fabrication. More particularly, the invention pertains to patterning of small features in integrated circuits.
As the designs of semiconductor circuitry become smaller, problems with the limitations and tolerances of the optical systems used in photolithography become more prevalent, especially with regards to the etching of small features.
For example, the problem of line end shortening (LES) is primarily the result of the limitations of the optics used in photolithography. Particularly, LES generally refers to the problem wherein a line of photoresist to be formed on a substrate ends up being shorter than what was intended by the design, e.g., shorter than the corresponding line on the mask. This is due largely to the fact that the amount of photoresist that is exposed through the mask to light generally will not exactly match that dictated by the mask due to diffraction of light around the edges between the opaque regions and the transparent regions of the mask and due to complex interactions between nearby features (commonly known as proximity effects). Aspects of line end shortening include corner rounding, wherein corners of the line become rounded, and overall line end shortening.
The issue of line end shortening is particularly relevant to the fabrication of gates in SRAM (Static Random Access Memory) transistors. Specifically, the material (typically polysilicon) deposited on a semiconductor to form the gate electrode of a transistor in a SRAM is generally called a line. With reference to exemplary FIG. 1, which shows a small portion of a SRAM integrated circuit, typically, a plurality of lines 112a, 112b, 112c of different transistors are straight, coaxial with each other, and are separated from each other by small gaps 114a, 114b. Furthermore, the lines 112 usually are perpendicularly intersected by other lines 116 (which, in this case, refer to shallow trench level isolation). The common area between 116 and 112 define the active area of a transistor. As SRAM transistors become smaller and more densely packed, the line tip to tip distances, i.e., the gaps 114, between the coaxial lines 112, become smaller.
For any given transistor design, there is a minimum amount of overhang 118 that must be maintained in order to prevent leakage between the gate, source and drain of the transistor. Also, there must be a minimum gap 114 between the ends of the lines 112 between adjacent transistors in order to prevent leakage between the adjacent transistors.
Accordingly, line end shortening is a particular problem with respect to the fabrication of SRAMs because it often is important to maintain a minimum overhang 118 and a minimum line end to line end spacing (hereinafter tip to tip gap) 114, while simultaneously making the tip to tip gap as small as possible in order to pack the transistors as tightly together as possible.
Several solutions have been proposed to address the line end shortening problem. In one such solution, the mask is designed with longer lines than desired based on the assumption that line end shortening will occur. However, as the tip to tip gap becomes smaller, this solution becomes less than optimal. Particularly, the lines on the mask can only be lengthened to a limited extent because the adjacent coaxial mask lines cannot meet as there would no longer be a gap between the line ends in the mask.
Furthermore, the amount of line end shortening and corner rounding that can occur can only be determined within a certain tolerance, and thus this solution can only be taken so far. Furthermore, the features on the mask themselves (e.g., the lengths of the lines on the mask) can be produced only to certain tolerances. Further, due to the limitations of the optics, any error in the mask can generally be expected to be magnified up to about six fold, and sometimes even more, when transferred to the semiconductor through photolithography.

Small feature integrated circuit fabrication

Infineon Technologies North America Corp.


A vehicle sun visor includes a visor body, a mirror mounted to the visor body, and a mirror cover slidably movable relative to the visor body along a reflective surface of the mirror between a closed position substantially covering the reflective surface of the mirror and an opened position for uncovering the reflective surface. A lighting device serves to illuminate a driver or a passenger when the mirror is used. A light control device serves to turn the lighting device from off to on as the mirror cover slides from the closed position to the opened position. The light control device also serves to control the intensity of light emitted from the lighting device in response to the position of the mirror cover.

1. Field of the Invention
The present invention relates to vehicle sun visors having lighting devices in conjunction with mirrors and mirror covers.
2. Description of the Related Art
Conventionally, various types of sun visors are known, such as a sun visor disclosed in Japanese Laid-Open Patent Publication No. 7-276984. The sun visor of this publication has a visor body and a mirror unit associated with the visor body. The mirror unit includes a mirror and a mirror cover that is vertically pivotally mounted to an upper edge of the mirror. The mirror cover can move between an upwardly pivoted position (i.e., an opened position) in order to uncover the reflective surface, and a downwardly pivoted position (i.e., a closed position) in order to cover the reflective surface.
A lighting device is mounted to a surface of the mirror cover. This surface faces a driver or a passenger when the mirror cover is in the opened position. An ON/OFF switch is assembled to a pivotal shaft of the mirror cover. The switch is turned on and off in response to the pivotal movement of the mirror cover. A slide switch is mounted to a side edge of the mirror in order to enable the adjustment of the intensity of the light emitted from the lighting device. In this way, the lighting device may be turned on when the mirror cover has been pivoted upward to the opened position. In addition, the light intensity may be adjusted by operating the slide switch.
However, according to the sun visor disclosed in the above publication, the ON/OFF switch and the slide switch are separately provided. Therefore, the construction of the sun visor is complicated. In addition, the operability is degraded because each of the above switches must be separately operated.

Vehicle sun visors having lighting devices


A centrifugal mass device having at least two centrifugal masses which are rotatable relative to each other against the effect of elastic elements of a torsional damping device. The output-side centrifugal mass, which is more distant from a drive, e.g., the crankshaft of an internal combustion engine, is run radially as well as axially relative to the drive-side centrifugal mass via a support. The support has an axial slide bearing that borders a grease chamber containing a viscous medium, which grease chamber accommodates, at least partially, the torsional damping device. To form a seal for the grease chamber, the axial slide bearing is radially encompassed along at least a portion of its axial extension by at least one axial projection provided on at least one of the centrifugal masses, whereby the axial projection is close to but separated by a gap from an associated region of the other centrifugal mass.

1. Field of the Invention
This invention relates to a centrifugal mass device with at least two centrifugal masses rotatable to one another.
2. Description of the Prior Art
A centrifugal mass device with centrifugal masses rotatable relative to each other against the effect of the elastic elements of a torsional damping device is known from DE 44 17 108 A1. The output-side centrifugal mass, which is more distant from a drive, e.g., the crankshaft of an internal combustion engine, is run radially as well as axially relative to the drive-side centrifugal mass via a support. The support is formed by means of a two-part slide bearing, which has a fixed, radially inner ring on the drive-side centrifugal mass and a fixed, radially outer ring on the output-side centrifugal mass. Because each of these two rings has a radial leg, as shown in the Offenlegungsschrift, the support acts as an axial slide bearing. The radial leg of the radially inner ring borders a grease chamber that accommodates the torsional damping device.
In such an embodiment of an axial slide bearing, as long as the axial force of a pressure spring of the friction clutch is active in the engaged state and/or the pre-load of a disengagement device (not shown) is active in the axial direction, the output-side centrifugal mass is pressed toward the drive-side centrifugal mass and, as a result, the radial legs of the two rings are held against each other. In this way, the grease chamber is sealed in the region of the support.
However, in other situations, e.g., during transport, assembly, or measurement of the centrifugal mass device, no axial pre-load is applied, and a gap can develop between the radial legs of the two rings. This gap can also occur--though only briefly--when, upon application of an axial pre-load, this pre-load is neutralized due to the wobbling movements of the output-side centrifugal mass when the friction clutch is in the disengaged state. Under these circumstances, the viscous medium contained in the grease chamber emerges from the centrifugal mass device via the support. The lack of viscous medium is then reflected in weaker damping behavior during operation of the centrifugal mass device.
The object of the invention is to provide a centrifugal mass device wherein, in the region of an axial slide bearing the emergence of viscous medium from a grease chamber onto the slide bearing is prevented.

Centrifugal mass device with an axial slide bearing as seal


A dental suction tool has a disposable sanitary plastic suction tip to prevent cross contamination from one patient to the next. The suction tip is formed as a generally cylindrical hollow tubing and made of disposable plastic material. One end of the suction tip has at least one beveled section along an outer wall surface of the suction tip so that the suction tip can be properly aligned in the dental suction tool. Alternatively, one end of the suction tip has at least one recess that is adapted to cooperate with a keying element in the dental suction tool to properly align the suction tip in the dental suction tool.

The present invention was developed to add further function to the widely accepted evacuation systems currently used for suction or aspiration. The concept of suction or aspiration in the dental office has its roots in the old fashioned spittoon. The spittoon was later replaced by the gravity flow cuspidor, then by the flush cup and finally by the suction tip/aspirator tip/vacuum tip which are interchangeable terms varying by the user and based on the size of the aperture in the device.
These dental suction instruments are used by dentists to remove fluids and other foreign objects that accrue in the patient's oral cavity during typical dental procedures. The conventional dental suction tool comprises a suction tip connected by a long tubing to a vacuum source. The dental suction tool can be configured to hang in the corner of the patient's mouth or is manipulated by the dentist to suction the oral cavity.
With the rising incidence of communicable diseases such as hepatitis and acquired immune deficiency syndrome, extreme care must be taken to prevent the transmission of germs (viral or bacteria) from one patient to the next. With the conventional suction devices, it is necessary to sterilize at least the tip of the suction device after each patient use. During the use of the suction device, water, saliva and blood from the patient's mouth is drawn into the tip for removal from the oral cavity. If cleaning and sterilization is not effected, it would be very easy to transfer infection from one patient to the next. Also, latent bacterial growth can be promoted in both the tip and the entire vacuum suction system lines because of the existence of this potentially contaminating material. To further mitigate this possibility of cross-contamination from one patient to the next, the routine sterilization of suction tips is desirable.
It is desirable to also supply light into the oral cavity to assist the dentist in performing necessary dental procedures. Most dental operatories have an overhead task lighting system with reflective surfaces that help concentrate the light on the patient's mouth. However, the dentist will often stand in the path of the light which minimizes the effectiveness of the overhead light. One of the major nuisances and frustrations in the practice of dentistry is the constant need for the dentist to spend time adjusting the direction of this overhead lighting.
Various dental tools have been provided with a light source to assist the dentist during various dental activities. For example, a typical dental drill will include a fiberoptic bundle that transmits light from a light source to the end of the dental drill which allows the dentist to provide light directly to the area in which the drilling is occurring. Representative of this technology are the disclosures shown in U.S. Pat. No. 4,507,085 (Mosimann) and U.S. Pat. No. 5,088,924 (Woodward).
Dental syringe tip handpieces have also been provided with a light source to illuminate the area into which the air and/or water are to be sprayed. Representative of these devices is the disclosure of U.S. Pat. No. 4,619,612 (Weber) which shows a fiberoptic bundle disposed down the center of a metal syringe tip assembly. A light bulb acts as the light source and is disposed in the interior of the handpiece. The syringe tip used in the disclosure of the Weber patent is a metal, non-disposable syringe tip which must be autoclaved prior to use on the next patient.
Previous attempts to use light in conjunction with a suction tip were done by running a fiberoptic bundle tangent and parallel to the suction tip. The optical conduit for the fiberoptic bundle was fixed to the suction tip by a series of clamps along the length of the suction tip. However, the results from this configuration were less than desirable for several reasons.
The fiberoptic bundles that were attached to the suction tips still needed to be sterilized before being used on the next patient. Fiberoptic bundles are not particularly amenable to the heat of sterilization and the expense and inconvenience of frequent replacement of these fiberoptic bundles can be prohibitive. It is also necessary to clean up the areas on the suction tip at which the clamps are attached and this can be quite cumbersome and time consuming. Another problem with this fiberoptic bundle configuration is that the light is positioned off-center from the suction tip so that the light being transmitted into the oral cavity of the patient still casts shadows from the suction tip, itself, which can do more harm than good.
The novel concept developed herein is to transmit light to the field of operation by transmitting a light source through a transparent plastic material which simultaneously serves as the suction tip of the dental suction device. The fact that the light is centered relative to the suction tip minimizes any shadows in the oral cavity and reduces the need for the dentist to rely on his overhead task lighting, which is constantly in need of adjustment.
It is proposed that the use of the present invention in conjunction with the light source that is coupled to the air/water syringe tip will provide sufficient light in the patient's oral cavity to obviate the need for the overhead task lighting and eliminate the time spent constantly adjusting this task lighting.
It is an object of the present invention to provide a disposable suction tip as part of the dental suction tool so that each patient can receive a clean and uncontaminated suction tip.
It is a feature of the present invention that the suction tip portion of a dental suction tool is made from a disposable plastic material.
It is an advantage of the present invention that cross-contamination between patients due to improperly cleaned or sterilized suction tips is eliminated because each patient is provided with a new, clean and uncontaminated suction tip that is only used on that patient.
It is a further object of the present invention to provide a useful source of light that can be transmitted into the oral cavity of the patient whenever the dentist is using a dental suction tool.
It is a further feature of the present invention to provide a light source at one end of the suction tip on the interior of the adaptor that holds the suction tip in the dental tool. Light from the light source is directed into one end of the suction tip and carried along the length thereof. At the opposite end of the suction tip, the light radiates from the suction tip and can be used to illuminate the oral cavity of the patient.
It is a further advantage of the present invention that a dentist will be able to illuminate the oral cavity using the same instrument that he is using to suction liquids and other foreign matter from the oral cavity of the patient. Any dental procedures that require use of the dental suction tool will be more easily, safely and effectively carried out because the dentist will be able to see exactly where in the oral cavity he is working.
It is a further object of the present invention to provide means for properly aligning the suction tip in the dental suction tool.
It is a further feature of the present invention to provide at one end of the suction tip at least one beveled section along an outer wall surface of the suction tip so that the suction tip can be properly aligned in the dental suction tool. Alternatively, one end of the suction tip is provided with at least one recess that is adapted to cooperate with a keying element in the dental suction tool to properly align the suction tip in the dental suction tool.
It is a further advantage of the present invention that a dentist will be able to properly align the suction tip in the dental suction tool.
Other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description.

Illuminated suction tool with disposable tip


A nonvolatile semiconductor memory device includes: a memory cell array having a plurality of memory cells arranged in a matrix; a reference bit line; a reference source line; at least one reference cell including first and second transistors serially connected between these lines; a reference word line connected to the gate of the first transistor; and a reference driver circuit configured to control the gate voltage of the second transistor.

The present disclosure relates to a nonvolatile semiconductor memory device, and more particularly to a technology of controlling a reference current.
At present, the workhorse of nonvolatile memory is flash memory. The flash memory however has problems of being large in power consumption and low in operation speed: a voltage as high as about 10 V is required to rewrite data, and the data rewrite time is of the order of microseconds or milliseconds. A circuit configuration of flash memory is disclosed in U.S. Pat. No. 5,917,753 (Patent Document 1), for example.
In recent years, development of novel nonvolatile memory devices that operate at low power and high speed is in progress. As one of nonvolatile memory devices, resistive random access memory (ReRAM) is known. The ReRAM, which achieves data rewrite of the order of nanoseconds and a voltage required for data rewrite of about 1.8 V, is operable at higher speed and lower power than flash memory.
As memory cells of the ReRAM, there are those configured as in FIGS. 14A and 14B, for example. FIG. 14A shows so-called 1T1R memory cells, where one memory cell comprises one selective transistor and one variable resistance element. FIG. 14B shows so-called cross-point memory cells, where one memory cell comprises one variable resistance element and one bidirectional diode.
The memory cell in FIG. 14A has a layout as shown in FIG. 15, for example. This memory cell has a four-layer structure, where a bit line BL is placed in a fourth layer M4 and a source line SL is placed in a first layer M1. A word line WL is a polysilicon interconnect. Since the polysilicon interconnect is high in wiring resistance and wiring capacitance, a backing interconnect WLX is provided in a second layer M2. The word line WL and the backing interconnect WLX are connected to each other at constant intervals. The interconnect layers are connected to one another through a via, and a variable resistance element RR is provided between a third layer M3 and the fourth layer M4 through the via.
Japanese Unexamined Patent Publication No. 2004-234707 (Patent Document 2) discloses a circuit configuration of ReRAM. In this ReRAM, a memory cell current is compared with a reference current by a sense amplifier, thereby determining data stored in a memory cell. In this relation, the operations of the ReRAM include read, write verify, delete verify, etc., and it is necessary to generate reference currents corresponding to these operations. Thus, a plurality of kinds of reference currents must be generated.
For example, the configuration in FIG. 4 of Patent Document 2 uses a reference cell having four circuits in each of which a fixed resistance element and a cell transistor are serially connected to each other. By selecting a desired one of the cell transistors, a reference current corresponding to the resistance value of the selected circuit is generated. As the fixed resistance elements of the reference cell, used generally are polysilicon resistance elements as shown in Wataru Otsuka et al., "A 4 Mb Conductive-Bridge Resistive Memory with 2.3 GB/s Read-Throughput and 216 MB/s Program Throughput," 2011 IEEE International Solid-State Circuits Conference Digest of Technical Papers, February 2011, P210-211.

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