The problem of how to select out of a large chemically accessible universe molecules representative of the diversity of that universe is resolved by the discovery of a method to validate molecular structural descriptors. Using the validated descriptors, optimally diverse subsets can be selected. In addition, from the universe, molecules with characteristics similar to a selected molecule can be identified. The validated descriptors also enable the generation of a huge virtual library of potential product molecules which could be formed by combinatorial arrangement of structural variations and cores. In this virtual library it is possible to search billions of possible product compounds in relatively short time frames.

Statement of the Problem
While the present invention is discussed with detailed reference to the search for and identification of pharmacologically useful chemical compounds, the invention is applicable to any attempt to search for and identify chemical compounds which have some desired physical or chemical characteristic(s). The broader teachings of this invention are easily recognized if a different functional utility or useful property describing other chemical systems is substituted below for the term "biological activity".
Starting with the serendipitous discovery of penicillin by Fleming and the subsequent directed searches for additional antibiotics by Waksman and Dubos, the field of drug discovery during the post World War II era has been driven by the belief that nature would provide many needed drugs if only a careful and diligent search for them was conducted. Consequently, pharmaceutical companies undertook massive screening programs which tested samples of natural products (typically isolated from soil or plants) for their biological properties. In a parallel effort to increase the effectiveness of the discovered "lead" compounds, medicinal chemists learned to synthesize derivatives and analogs of the compounds. Over the years, as biochemists identified new enzymes and biological reactions, large scale screening continued as compounds were tested for biological activity in an ever rapidly expanding number of biochemical pathways. However, proportionately fewer and fewer lead compounds possessing a desired therapeutic activity have been discovered. In an attempt to extend the range of compounds available for testing, during the last few years the search for unique biological materials has been extended to all corners of the earth including sources from both the tropical rain forests and the ocean. Despite these and other efforts, it is estimated that discovery and development of each new drug still takes about 12 years and costs on the order of 350 million dollars.
Beginning approximately twenty-five years ago, as bioscientists learned more about the chemical and stereochemical requirements for biological interactions, a variety of semi-empirical, theoretical, and quantitative approaches to drug design were developed. These approaches were accelerated by the availability of powerful computers to perform computational chemistry. It was hoped that the era of "rational drug design" would shorten the time between significant discoveries and also provide an approach to discovering compounds active in biological pathways for which no drugs had yet been discovered. In large part, this work was based on the accumulated observation of medicinal chemists that compounds which were structurally similar also possessed similar biological activities. While significant strides were made using this approach, it too, like the mass screening programs, failed to provide a solution to the problem of rapidly discovering new compounds with activities in the ever increasing number of biological pathways being elucidated by modern biotechnology.
During the past four or five years, a revised screening approach has been under development which, it was hoped, would accelerate the pace of drug discovery. In fact, the approach has been remarkably successful and represents one of the most active areas in biotechnology today. This new approach utilizes combinatorial libraries against which biological assays are screened. Combinatorial libraries are collections of molecules generated by synthetic pathways in which either: 1) two groups of reactants are combined to form products; or 2) one or more positions on core molecules are substituted by a different chemical constituent/moiety selected from a large number of possible constituents.
Two fundamental ideas underlie combinatorial screening libraries. The first idea, common to all drug research, is that somewhere amongst the diversity of all possible chemical structures there exist molecules which have the appropriate shape and binding properties to interact with any biological system. The second idea is the belief that synthesizing and testing many molecules in parallel is a more efficient way (in terms of time and cost) to find a molecule possessing a desired activity than the random testing of compounds, no matter what their source. In the broadest context, these ideas require that, since the binding requirements of a ligand to the biological systems under study (enzymes, membranes, receptors, antibodies, whole cell preparations, genetic materials, etc.) are not known, the screened compounds should possess as broad a range of characteristics (chemical and physical) as possible in order to increase the likelihood of finding one that is appropriate for any given biological target. This requirement for a screening library is reflected in the term "diversity"-essentially a way of suggesting that the library should contain as great a dissimilarity of compounds as possible.
However, as is immediately apparent, a combinatorial approach to synthesizing molecules generates an immense number of compounds many with a high degree of structural similarity. In fact, the number of compounds synthetically accessible with known organic reactions exceeds by many orders of magnitude the numbers which can actually be made and tested. One area where these ideas were first explored is in the design of peptide libraries. For a library of five member peptides synthesized using the 20 naturally occurring amino acids, 3,200,000, (205) different peptides may be constructed. The number of combinatorial possibilities increases even more dramatically when non-peptide combinatorial libraries are considered. With non-peptide libraries, the whole synthetic chemical universe of combinatorial possibilities is available. Library sizes ranging from 5×107 to 4×1012 molecules are now being discussed. The enormous universe of chemical compounds is both a blessing and a curse to medicinal chemists seeking new drugs. On the one hand, if a molecule exists with the desired biological activity, it should be included in the chemical universe. On the other hand, it may be impossible to find. Thus, the principal focus of recent efforts has been to define smaller screening subsets of molecules derivable from accessible combinatorial syntheses without losing the inherent diversity of an accessible universe.
To date, in order to narrow the focus of the search and reduce the number of compounds to be screened, attention has been directed to designing biologically specific libraries. Thus, many combinatorial screening libraries existing in the prior art have been designed based on prior knowledge about a particular biological system such as a known pharmacophore (a geometric arrangement of structural fragments abstracted from molecular structures known to have activity). Even with this knowledge, molecules are included in these prior art libraries based on intuition—"seat of the pants" estimations of likely similarity based on an intuitive "feel" for the systems under study. This procedure is essentially pseudo-random screening, not rational library design. Several biotechnology startup companies have developed just such proprietary libraries, and success using combinatorial libraries has been achieved by sheer effort. In one example 18 libraries containing 43 million compounds were screened to identify 27 active compounds1. With library searches of this magnitude, it is most likely that the enormous number of inactive molecules [(43×106)−27] must have included staggering numbers of redundantly inactive molecules—molecules not significantly distinguishable from one another—even in libraries designed with a particular biological target in mind. Clearly, when searching for a lead molecule which interacts with an uncharacterized biological target, approaches requiring knowledge of the biological targets will not work. But finding such a lead is exactly the case for which it is hoped general purpose screening libraries can be designed. If the promise of combinatorial chemistry is ever to be fully realized, some rational and quantitative method of reducing the astronomical number of compounds accessible in the combinatorial chemistry universe to a number which can be usefully tested is required. In other words, the efficiency of the search process must be increased. For this purpose, a smaller rationally designed screening library, which still retains the diversity of the combinatorially accessible compounds, is absolutely necessary.
Thus, there are two criteria which must be met by any screening library subset of some universe of combinatorially accessible compounds. First, the diversity, the dissimilarity of the universe of compounds accessible by some combinatorial reaction, must be retained in the screening subset. A subset which does not contain examples of the total range of diversity in such a universe would potentially miss critical molecules, thereby frustrating the very reason for the creation of the subset. Second, for efficient screening, the ideal subset should not contain more than one compound representative of each aspect of the diversity of the larger group. If more than one example were included, the same diversity would be tested more than once. Such redundant screening would yield no new information while simultaneously increasing the number of compounds which must be synthesized and screened. Therefore, the fundamental problem is how to reduce to a manageable number the number of compounds that need to be synthesized and tested while at the same time providing a reasonably high probability that no possible molecule of biological importance is overlooked. (In this regard, it should be recognized that the only way of absolutely insuring that all diversity is represented in a library is to include and test all compounds.) A conceptual analogy to the problem might be: what kind of filter can be constructed to sort out from the middle of a blinding snowstorm individual snowflakes which represent all the classes of crystal structures which snowflakes can form?
The fundamental question plaguing progress in this area has been whether the concept of the diversity of molecular structure can be usefully described and quantified; that is, how is it possible to compare/distinguish the physical and chemical properties determinative of biological activity of one molecule with that of another molecule? Without some way to quantitatively describe diversity, no meaningful filter can be constructed. Fortunately, for biological systems, the accumulated wisdom of bioscientists has recognized a general principle alluded to earlier which provides a handle on this problem. As framed by Johnson and Maggiora2, the principle is simply stated as: "structurally similar molecules are expected to exhibit similar (biological) properties." Based on this principle, quantifying diversity becomes a matter of quantifying the notion of structural similarity. Thus, for design of a screening subset of a combinatorial library (hereafter referred to as a "combinatorial screening library"), it should only be necessary to identify which molecules are structurally similar and which structurally dissimilar. According to the selection criteria outlined above, one molecule of each structurally similar group in the combinatorially accessible chemical universe would be included in the library subset. Such a library would be an optimally diverse combinatorial screening library. The problem for medicinal chemists is to determine how the intuitively perceived notions of structural similarity of chemical compounds can be validly quantified. Once this question is satisfactorily answered, it should be possible to rationally design combinatorial screening libraries.
Prior Art Approaches
Many descriptors of molecular structure have been created in the prior art in an attempt to quantify structural similarity and/or dissimilarity. As the art has recognized, however, no method currently exists to distinguish those descriptors that quantify useful aspects of similarity from those which do not. The importance of being able to validate molecular descriptors has been a vexing problem restricting advances in the art, and, before this invention, no generally applicable and satisfactory answer had been found. The problem may be conceptualized in terms of a multidimensional space of structurally derivable properties which is populated by all possible combinatorially accessible chemical compounds. Compounds lying "near" one another in any one dimension may lie "far apart" from one another in another dimension. The difficulty is to find a useful design space—a quantifiable dimensional space (metric space) in which compounds with similar biological properties cluster; ie., are found measurably near to each other. What is desired is a molecular structural descriptor which, when applied to the molecules of the chemical universe, defines a dimensional space in which the "nearness" of the molecules with respect to a specified characteristic (ie.; biological activity) in the chemical universe is preserved in the dimensional space. A molecular structural descriptor (metric) which does not have this property is useless as a descriptor of molecular diversity. A valid descriptor is defined as one which has this property.
In light of the above, it should be noted that there is a difference between a descriptor being valid and being perfect. There may or may not be a "perfect" metric which precisely and quantitatively maps the diversity of compounds (much less those of biological interest). However, a good approximation is sufficient for purposes of designing a combinatorial screening library and is considered valid/useful. Acceptance of this validation/usefulness criteria is essentially equivalent to saying that, if there is a high probability that if one molecule is active (or inactive), a second molecule is also active (or inactive), then most of the time sampling one of the pair will be sufficient. Restating this same principle with a slightly different emphasis highlights another feature, namely: the design criteria for combinatorial screening libraries should yield a high probability that, for any given inactive molecule, it is more probable to find an active molecule somewhere else rather than as a near neighbor of that inactive molecule. While this is a probabilistic approach, it emphasizes that a good approximation to a perfect metric is sufficient for purposes of designing a combinatorial screening library as well as in other situations where the ability to discriminate molecular structural difference and similarities is required. A perfect descriptor (certainty) for pharmacological searching is not needed to achieve the required level of confidence as long as it is valid (maps a subspace where biological properties cluster).
The typical prior art approach for establishing selection criteria for screening library subsets relied on the following clustering paradigm: 1) characterization of compounds according to a chosen descriptor(s) (metric[s]); 2) calculation of similarities or "distances" in the descriptor (metric) between all pairs of compounds; and 3) grouping or clustering of the compounds based on the descriptor distances. The idea behind the paradigm is that, within a cluster, compounds should have similar activities and, therefore, only one or a few compounds from each cluster, which will be representative of that cluster, need be included in a library. The actual clustering is done until the prior art user feels comfortable with the groupings and their spacing. However, with no knowledge of the validity/usefulness of the descriptor employed, and no guidance with respect to the size or spacing of clusters to be expected from any given descriptor, prior art clustering has been, at best, another intuitive "seat of the pants" approach to diversity measurement.
The prior art describes the construction and application of many molecular structural descriptors while all the while tacitly acknowledging that little progress has been made towards solving the fundamental problem of establishing their validity. The field has nevertheless proceeded based on the belief/faith that, by incorporating in the descriptors certain measures which had been recognized in QSAR studies as being important contributors to defining structure-activity relationships, valid/useful descriptors would be produced. In a leading method representative of this prior art approach to defining a similarity descriptor, E. Martin et al.3 construct a metric for quantifying structural similarity using measures that characterize lipophilicity, shape and branching, chemical functionality, and receptor recognition features. (For the reasons set forth later in relation to the present invention, Martin et al. applied their metric to the reactants which would be used in combinatorial synthesis.) This large set of measures is used to generate a statistically blended metric consisting of a total of 16 properties for each individual reactant studied (5 shape descriptors, 5 measures of chemical functionality, 5 receptor binding descriptors, and one lipophilicity property). This generates a 16 dimensional property space. The 16 properties are simultaneously displayed in a circular "Flower Plots" graphical environment, where each property is assigned a petal. All the plots together visually display how the diversity of the studied reactants is distributed through the computed property space. Martin acknowledges that the plots ". . . cannot, of course, prove that the subset is diverse in any 'absolute' sense, independent of the calculated properties." (Martin at 1434)
In another approach relating to peptoid design, Martin et al.4 have characterized the varieties of shape that an unknown receptor cavity might assume by a few assemblages of blocks, called "polyominos". Candidates for a combinatorial design are classified by the types of polyominos into which they can be made to fit, or "docked". The 7 flexible polyomino shape descriptors are added to the previously defined 16 descriptors to yield a 23 dimensional property space. Martin has demonstrated that the docking procedure generates for a methotrexate ligand in a cavity of dihydrofolate reductase nearly the correct structure as that established by X-ray diffraction studies. The docking procedure, which must be applied to every design candidate for each polyomino, requires a considerable amount of CPU time (is computationally expensive). However, a problem with this approach is the conceptually severe (unjustified) approximation of representing all possible irregularly shaped receptor cavities by only about a dozen assemblies of smooth-sided polyomino cubes. Martin has also presented no validation of the approach, which in this case, would be a demonstration that molecules which fit into the same polyominos tend to have similar biological properties.
One approach which has been taken to try to empirically assess the relative validity of prior art metrics has been to survey the metrics to see if any of them appeared to be superior to any others as judged by clustering analysis. Y. C. Martin et al.5 have reported that 3D fingerprints, collections of fragments defined by pairs of atoms and their accessible interatomic distances, perform no better than collections of 2D fragments in defining clusters that separate biologically active from inactive compounds. As will be seen later, some of this work pointed towards the possible validity of one metric, but the authors concentrated on the comparative clustering aspects and did not follow up on the broader import of the data.
W. Hemdon6 among others has pointed out that an experimentally determined similarity QSAR is, by definition, a good test of the validity of that similarity concept for the biological system from which it is derived and may have some usefulness in estimating diversity for that system. However, QSARs essentially map only the space of a particular receptor, do not provide information about the validity of other descriptors, and would be generally inapplicable to construction of a combinatorial screening library designed for screening unknown receptors or those for which no QSAR data was available.
Finally, D. Chapman et al.7 have used their "Compass" 3D-QSAR descriptor which is based on the three dimensional shape of molecules, the locations of polar functionalities on the molecules, and the fixation entropies of the molecules to estimate the similarity of molecules. Essentially, using the descriptor, they try to find the molecules which have the maximum overlap (in geometric/cartesian space) with each other. The shape of each molecule of a series is allowed to translate and rotate relative to each other molecule and the internal degrees of freedom are also allowed to rotate in an iterative procedure until the shapes with greatest or least overlap similarity are identified. Selecting 20 maximally diverse carboxylic acids based on seeking the maximally diverse alignment of each of the 3000 acids considered took approximately 4 CPU computing weeks by their method. No indication was given of whether their descriptor was valid in the sense defined above, and, clearly, such a procedure would be too time consuming to apply to a truly large combinatorial library design.
One way in which many of the prior art approaches attempt to work around the problem of not knowing if a molecular structural descriptor is valid is to try, when clustering, to maximize as much as possible the distance between the clusters from which compounds will be selected for inclusion in the screening library subset. The thinking behind this approach is that, if the clusters are far enough apart, only molecules diverse from each other will be chosen. Conversely, it is thought that, if the clusters are close together, oversampling (selection of two or more molecules representative of the same elements of diversity) would likely occur. However, as we have seen, if the metric used in the cluster analysis is not initially valid (does not define a subspace in which molecules with similar biological activity cluster), then no amount of manipulation will prevent the sample from being essentially random. Worse yet, an invalid metric might not yield a selection as good as random! The acknowledgement by Martin quoted above is a recognition of the prior art's failure to yet discover a general method for validating descriptors.
Another related problem in the prior art is the failure to have any objective manner of ascertaining when the library subset under design has an adequate number of members; that is, when to stop sampling. Clearly, if nothing is known about the distribution of the diversity of molecules, one arbitrary stopping point is as good as any other. Any stopping point may or may not sample sufficiently or may oversample. In fact, the prior art has not recognized a coherent quantitative methodology for determining the end point of selection. Essentially, in the prior art, a metric is used to maximize the presumed differences between molecules (typically in a clustering analysis), and a very large number of molecules are chosen for inclusion in a screening library subset based on the belief that there is safety in numbers; that sampling more molecules will result in sampling more of the diversity of a combinatorially accessible chemical space. As pointed out earlier, however, only by including all possible molecules in a library will one guarantee that all of the diversity has been sampled. Short of such total sampling, users of prior art library subsets constructed along the lines noted above do not know whether a random sample, a representative sample, or a highly skewed sample has been screened.
Several other problems flow from the inability to rationally select a combinatorial screening library for optimal diversity and these are related both to the chemistry used to create the combinatorial library and the screening systems used. First, because many more molecules may have to be synthesized than may be needed, mass synthetic schemes have to be devised which create many combinations simultaneously. In fact, there is a good deal of disagreement in the prior art as to whether compounds should be synthesized individually or collectively or in solution or on solid supports. Within any synthetic scheme, an additional problem is keeping track of and identifying the combinations created. It should be understood that, where relatively small (molecular weight of less than about 1500) organic molecules are concerned, generally standard, well known, organic reactions are used to create the molecules. In the case of peptide like molecules, standard methods of peptide synthesis are employed. Similarly for polysaccharides and other polymers, reaction schemes exist in the prior art which are well known and can be utilized. While the synthesis of any individual combinatorial molecule may be straightforward, much time and effort has been and is still being expended to develop synthetic schemes in which hundreds, thousands, or tens of thousands of combinatorial combinations can be synthesized simultaneously.
In many synthetic schemes, mixtures of combinatorial products are synthesized for screening in which the identity of each individual component is uncertain. Alternatively, many different combinatorial products may be mixed together for simultaneous screening. Each additional molecule added to a simultaneous screen means that many fewer individual screening operations have to be performed. Thus, it is not unusual that a single assay may be simultaneously tested against up to 625 or more different molecules. Not until the mixture shows some activity in the biological screening assay will an attempt be made to identify the components. Many approaches in the prior art therefore face "deconvolution" problems; ie. trying to figure out what was in an active mixture either by following the synthetic reaction pathway, by resynthesizing the individual molecules which should have resulted from the reaction pathway, or by direct analysis of duplicate samples. Some approaches even tag the carrier of each different molecule with a unique molecular identifier which can be read when necessary. All these problems are significantly decreased by designing a library for optimal diversity.
Another major problem with the inclusion of multiple and potentially non-diverse compounds in the same screening mixture is that many assays will yield false positives (have an activity detected above a certain established threshold) due to the combined effect of all the molecules in the screening mixture. The absence of the desired activity is only determined after expending the time, effort, and expense of identifying the molecules present in the mixture and testing them individually. Such instances of combined reactivity are reduced when the screening mixture can be selected from molecules belonging to diverse groups of an optimally designed library since it is not as likely that molecules of different (diversity) structures would likely produce a combined effect.
It is clear that a great deal of cleverness has been expended in actually manufacturing the combinatorial libraries. While the basic chemistry of synthesizing any given molecule is straight forward, the next advance in the development of combinatorial chemistry screening libraries will be optimization of the design of the libraries.
Further problems in the prior art arise in the attempt to follow up leads resulting from the screening process. As noted above, many libraries are designed with some knowledge of the receptor and its binding requirements. While, within those constraints, all possible combinatorial molecules are synthesized for screening, finding a few molecules with the desired activity among such a library yields no information about what active molecules might exist in the universe accessible with the same combinatorial chemistry but outside the limited (receptor) library definition. This is an especially troubling problem since, from serendipitous experience, it is well known that sometimes totally unexpected molecules with little or no obvious similarity to known active molecules exhibit significant activity in some biological systems. Thus, even finding a candidate lead in a library whose design was based on knowledge of the receptor is no guarantee that the lead can be followed to an optimal compound. Only a rationally designed combinatorial screening library of optimal diversity can approach this goal.
For prior art library subsets designed around the use of some descriptor to cluster compounds, similar problems may exist. In such a library design, one or at most a few compounds will have been selected from each cluster. Only if the descriptor is valid, does such a selection procedure make sense. If the descriptor is not valid, each cluster will contain molecules representative of many different diversities and selecting from each cluster will still have resulted in a random set of molecules which do not sample all of the diversity present. Since the prior art does not possess a generally applicable method of validating descriptors, all screening performed with prior art libraries is suspect and may not have yielded all the useful information desired about the larger chemical universe from which the library subsets were selected.
Finally, as the expense in time and effort of creating and screening combinatorial libraries increases, the question of the uniqueness of the libraries becomes ever more critical. Questions can be asked such as: 1) does library "one" cover the same diversity of chemical structures as library "two"; 2) if libraries "one" and "two" cover both different and identical aspects of diversity, how much overlap is there; 3) what about the possible overlap with libraries "three", "four", "five", etc.? To date, the prior art has been unable to answer these questions. In fact, assumptions have been made that as long as different chemistries were involved (ie., proteins, polysaccharides, small organic molecules), it was unlikely that the same diversity space was being sampled. However, such an assumption contradicts the well known reality that biological receptors can recognize molecular similarities arising from different structures. When screening for compounds possessing activity for undefined biological receptors, there is no way of telling a priori which chemistry or chemistries is most likely to produce molecules with activity for that receptor. Thus, screening with as many chemistries as possible is desired but is only really practical if redundant sampling of the same diversity space in each chemistry can be avoided. The prior art has not provided any guidance towards the resolution of these problems.

Virtual library searchable for possible combinatorially derived product molecules having desired properties without the necessity of generating product structures


A device for sensing a sudden stop of a machine is disclosed. A spring-biased weight wheel is selectively moved in response to a predetermined extent of inertia force. A beam shutter is connected to the weight wheel and is selectively inserted into an optical sensor, thus intercepting a light beam of the sensor and allowing the sensor to generate a sudden stop signal. The spring force for the weight wheel is adjustable by controlling the position of a movable support plate and so the sensitivity of the device is controllable. The device is only started in response to the predetermined extent of inertial force, thus being almost completely prevented from being unexpectedly started by normal operational vibrations or rotating motions of the machine.

1. Field of the Invention
The present invention relates, in general, to a device for sensing a sudden stop of a machine such as a car or an industrial robot and, more particularly, to a sudden stop sensing device capable of quickly and precisely sensing a sudden stop of a car or an actuating arm of an industrial robot and outputting an electric signal informing a driver or an operator of such a sudden stop.
2. Description of the Prior Art
As well known to those skilled in the art, several types of devices for sensing a sudden stop of machines such as cars or industrial robots are proposed and practically used.
A known sudden stop sensing device for machines is shown in FIG. 1A. The known sensing device of FIG. 1A is comprised of a sealed tank 101 which is almost half filled with mercury 102. Two electrodes are set on one side wall of the tank 101 in such a manner that one electrode 103 is positioned under the horizontal normal level of the mercury 102, thus being always immersed in the mercury 102, and the other electrode 103' is positioned above the normal level of the mercury 102, thus being not immersed in the mercury 102. In the event of a sudden stop of a car or an industrial robot, the mercury 102 inertially leans to one side, thus causing the mercury level to be inclined and bringing the two electrodes 103 and 103' into a conductive state as shown by the phantom line of FIG. 1. When the two electrodes 103 and 103' are brought into such a conductive state as described above, an electric current flows in the sensing device, thus causing the device to generate a sudden stop signal.
FIG. 1B shows the construction of a known sudden stop sensing device for machines such as cars or industrial robots in accordance with another embodiment. The sensing device of FIG. 1B is comprised of a sealed tank which is provided with a slope therein. Two electrodes 103 and 103' are set on the side wall of the tank at a position around the highest edge of the slope, while a steel ball 104 is movably laid on the slope. The ball 104 normally rests on the lowermost edge of the slope by its own weight. However, in the event of a sudden stop of a car or a robot, the ball 104 inertially rolls on the slope, thus reaching the highest edge of the slope and coming into common contact with the two electrodes 103 and 103'. In such a case, an electric current flows in the sensing device and generates a sudden stop signal.
However, the above sudden stop sensing devices have the following problems. First, the sensitivity of the devices cannot be adjusted in accordance with the use of the devices. Second, it is almost impossible to give an operational deflection to the sensing devices. In addition, the sensing devices may be unexpectedly operated by normal operational vibrations or rotating motions of machines, thus having a reduced operational reliability.
Particularly, the sensing device with mercury may cause environmental pollution and may result in a serious hygienic problem for users. Another problem experienced in the known sensing devices is that it is impossible to measure the extent of a sudden stop.

Device for sensing sudden stop of machine


A method for making a strain aging resistant steel comprises adding boron to the steel, wherein substantially all of the boron in the steel forms boron nitride. A method for making steel comprises adding a nitride-forming element to the steel to lower the free nitrogen content of the steel to a free nitrogen content specification. A high-carbon steel contains boron nitride, wherein the free nitrogen content of the steel is less than 80 ppm. A strain aging resistant steel wherein the carbon content of the steel is between about 0.54 percent and about 0.75 percent.

The present disclosure relates generally to methods for modifying the chemistry in steel. More specifically, the method relates to forming a strain aging resistant steel by using nitride-forming elements, such as boron, to limit the free nitrogen content in high-carbon steel, or to meet a free nitrogen content specification in either high or low-carbon steel.
Steel is generally classified as either high-carbon steel or low-carbon steel. Generally, low-carbon steel contains less than 0.25 percent carbon, and high-carbon steel contains more than 0.25 percent carbon. Low-carbon steel is tough and ductile and is used for screws, nails, automotive body panels, and similar products that do not have critical strength requirements. Toughness is defined as the capacity of the steel to absorb energy without fracturing. Ductility is defined as the ability of steel to undergo permanent changes in shape without fracturing at room temperature.
High-carbon steel is much harder than low-carbon steel due to the presence of both iron carbide (cementite) and iron that form pearlite in the steel. High-carbon steel is used for manufacturing parts that have critical strength requirements, such as shafts, axles, gears, crankshafts, couplings, forgings, rails, railway wheels, and rail axles. High-carbon steel can be heat-treated to high hardness, but loses its toughness and ductility. Hardness is defined as the degree to which the steel will resist cutting, abrasion, penetration, bending and stretching. High tensile strength typically corresponds with high hardness.
One method for making steel products is by refining iron ore into steel. First, iron ore is mined from the earth and transported to a steel mill. The iron ore is then mixed with limestone and coal and heated in a blast furnace. The blast furnace melts the iron ore and removes most of the impurities from the liquid iron, creating a product called pig iron. The carbon content of the pig iron is too high for most steel products, so the pig iron is either further refined in its liquid form or cast into ingots for later use. In either case, the pig iron must be refined to reduce the carbon content and form usable liquid steel. The liquid steel may then be cast into slabs or billets for later processing into steel products.
A downside to this method for making steel products is the expense associated with mining and refining the iron ore into pig iron. One solution is to use direct reduced iron, which is iron ore that has been crushed and refined using large amounts of natural gas. However, the economic attractiveness of direct reduced iron is highly dependent upon the price of natural gas; therefore, direct reduced iron is not always a viable option. Steel mills have found that the use of scrap steel is an attractive alternative to either pig iron or direct reduced iron. The scrap steel is melted into liquid steel using an electric arc furnace or a basic oxygen furnace. The liquid steel can then be cast into slabs or billets. If an electric arc furnace is used, the furnace is charged with the scrap steel, and three graphite electrodes inside the furnace create electric arcs that melt the steel scrap into liquid steel. By contrast, if a basic oxygen furnace is used, the furnace is charged with a mixture of scrap and liquid pig iron, and oxygen is blown into the liquid steel to melt the scrap and purify the steel. The liquid steel is then transferred to a ladle metallurgy furnace (LMF) where the chemistry of the liquid steel is adjusted to meet a steel specification. The liquid steel may then be used to make steel products. The use of scrap steel in an electric arc furnace is typically the most cost-effective method for manufacturing steel products.
A commonly manufactured steel product is steel wire. Steel mills manufacture steel wire by forming a billet, rolling the billet into a steel rod, and then cold drawing the rod to form a wire. Cold drawing is the process of forcing a steel rod though a die to elongate and reduce its diameter. The steel rod is not heated before or as it is being forced through the die, hence the name "cold drawing." When the steel rod exits the die, the rod is called a wire. The cold drawing process may be repeated using increasingly smaller diameter dies to produce a wire of any diameter. The wire may be heat treated after wire drawing for improved mechanical properties. The wire may then be sold as bulk wire or may be formed into wire products, such as lacing wire or springs.
One problem that occurs when wire is cold drawn is strain aging. Strain aging is a condition where the ductility of the steel is reduced such that the steel becomes brittle, and therefore cracks and breaks rather than bends during the subsequent forming process. There are two main types of strain aging: dynamic strain aging and static strain aging. Dynamic strain aging occurs when the rod is cold drawn to form the wire. Static strain aging occurs between the time when the wire is cold drawn and the time when it is formed into a wire product. Strain aging is a significant problem in the steel industry and has been widely discussed in the prior art.
One of the primary causes of both dynamic and static strain aging is the presence of large quantities of "free nitrogen" dissolved within the steel. All of the free nitrogen dissolved within the steel is present as atomic nitrogen. Experiments have shown that when the nitrogen content of steel is greater than about 80 ppm, the steel will exhibit strain aging, and that strain aging is substantially reduced or eliminated when the nitrogen content of steel is below about 65 ppm, about 60 ppm, and preferably about 50 ppm. On an atomic level, strain aging is caused by the relatively small nitrogen atoms impeding the movement of dislocations within the iron atom matrix as the steel passes though the die. It is widely believed that if the movement of free nitrogen within the iron matrix is reduced or "stabilized," then dislocations can move easier within the iron matrix and strain aging will be reduced or eliminated. Therefore, a need exists for a method of making steel in which the free nitrogen in the steel is stabilized, thereby increasing the steel's resistance to strain aging.
Table 1 below outlines the nitrogen content of steel by different processes:
TABLE 1Steel Making ProcessTypical Nitrogen ContentBasic Oxygen Furnace Using Pig Iron20-40ppmand Steel ScrapElectric Arc Furnace Using Steel Scrap50-80ppmand Combinations of Pig Iron andDirect Reduced IronElectric Arc Furnace Using Steel Scrap50-100ppmOnlyThus, strain aging is particularly problematic in steel produced using an electric arc furnace because such steel has a higher nitrogen content. This is due, in part, to the use of scrap steel, which has a higher nitrogen content than pig iron or direct reduced iron. As a result, the liquid steel formed from scrap steel has a higher nitrogen content than the liquid steel formed from either pig iron or direct reduced iron. In addition, the electric arc from the electrodes causes molecular nitrogen in the air (N2) to dissociate into atomic nitrogen, which is easily absorbed by the liquid steel. Thus, unless the steel mill implements a nitrogen-reduction process, the nitrogen content of the solidified steel will be even higher than the nitrogen content of the steel scrap used to charge the furnace.
The conventional methods for controlling the nitrogen content of the steel involve the use of additional carbon in the charge, additional oxygen during refining, shielding gases during refining, and/or shrouding equipment during transfer and casting. One of the chemical reactions that occurs in the liquid steel is the interaction of carbon and oxygen, which produces carbon monoxide (CO). Because one of the byproducts of the carbon-oxygen reaction is removal of nitrogen from the liquid steel, the amount of carbon and/or oxygen in the liquid steel can be increased to control the nitrogen content of the steel. The carbon content can be increased by using additional charge carbon, injected carbon, pig iron, or direct reduced iron in the steel. The oxygen content can be increased by adding additional oxygen gas to the liquid steel. In either case, the modified refining process requires more raw materials and/or more expensive raw materials and more processing time than steel production methods in which the nitrogen content is not controlled. An additional method of controlling the nitrogen content of the steel is to use a shielding gas, such as argon, to stir the steel and shield the steel from the nitrogen in the atmosphere. By bubbling the shielding gas through the liquid steel to stir it and covering the surface of the liquid steel with a layer of the shielding gas, the amount of nitrogen the steel absorbs from the atmosphere can be controlled. Moreover, the amount of nitrogen the steel absorbs from the atmosphere can be controlled by using shrouding equipment when transferring the steel between the melting furnace, the LMF, and the caster. Shrouding equipment is also effective at controlling the amount of nitrogen the steel absorbs from the atmosphere when the steel is being cast.
The aforementioned methods for controlling the nitrogen content of the steel are not preferred because they significantly increase the cost of producing the steel and/or substantially reduce the throughput rate of steel production. The use of additional charge and injected carbon and carbon in the form of pig iron and/or direct reduced iron increases the cost of the raw materials. The use of additional oxygen during refining increases the cost of the raw materials and requires additional refining time, thereby decreasing the throughput rate of the steel production. Shielding gases, such as argon, increase the production cost of the steel because the shielding gas is generally not recoverable once used. Finally, the use of shrouding equipment increases the capital cost of the steel mill, which when amortized over the life of the equipment, increases the production cost of the steel. If a method for reducing the nitrogen content of the steel existed, then the aforementioned methods for controlling the nitrogen content of the steel would be unnecessary. In other words, if a method for reducing the nitrogen in the steel existed, then steel could be produced without regard for its nitrogen content and the nitrogen content of the steel could be reduced using the nitrogen reduction method. Consequently, a need exists for a method of reducing the nitrogen content of steel.
The conventional methods of reducing the nitrogen content of steel are also not preferred due to concerns about the costs and/or lowered productivity associated with these methods. Another method for limiting the nitrogen content of steel is to refine the steel using a basic oxygen furnace instead of an electric arc furnace. However, basic oxygen furnaces have two disadvantages: they are more expensive to install and operate and they require a charge comprising a mixture of scrap and liquid pig iron. Another method for limiting the nitrogen content in steel is to use a vacuum degasser on the LMF. A vacuum degasser operates under the principle that the nitrogen in the steel is in equilibrium with the nitrogen in the air above the liquid steel. The vacuum degasser lowers the pressure of the air (i.e. creates a vacuum) above the liquid metal, thereby lowering the partial pressure of the nitrogen in the air and causing the nitrogen in the steel to transfer from the liquid phase to the gaseous phase. However, vacuum-degassing equipment is expensive to purchase, install, and operate. The vacuum degassing process is also relatively time consuming because of the slowness in removing nitrogen from liquid steel under vacuum, which lowers the throughput rate of the steel mill. Consequently, a need exists for a simple, quick, and relatively inexpensive method to reduce the free nitrogen content in steel, thereby creating a strain aging resistant steel.

Method for making strain aging resistant steel


An electrostatic chuck for supporting a semiconductor wafer, including: a chuck body having a dielectric region and an insulating region, the insulating region having a higher electrical resistivity than the dielectric region, an electrode embedded in the chuck body, and a barrier layer provided between dielectric region and the insulating region.

1. Field of the Invention
The present invention is generally directed to electrostatic chucks for use in semiconductor fabrication to hold semiconductor wafers in place for processing operations. Particularly, the present invention is directed to electrostatic chucks having tailored electrical resistivity properties and/or tailored compositions for improved performance, as well as methods for processing semiconductor wafers using such an electrostatic chuck.
2. Description of the Related Art
Electrostatic chucks, also know as susceptors, are employed to support substrates such as semiconductor (silicon) wafers during the manufacture of semiconductor devices. Electrostatic chucks are generally fabricated from ceramic materials, including aluminum nitride (AlN), which has a number of desirable properties. Such properties include desirable shock resistance, thermal conductivity, thermal expansion properties, and erosion and corrosion resistance in the semiconductor fabrication environment, which many times includes a corrosive plasma.
While various types of electrostatic chucks have been utilized in semiconductor fabrication, Coulombic and Johnson-Rahbek electrostatic chucks have been primarily used. Typically, Johnson-Rahbek electrostatic chucks have a dielectric ceramic body which has an electrical resistivity of 108 to about 1013 ohm-cm, such as 109 to about 1011 ohm-cm at working temperature. Working temperature may vary, such as room temperature for dry etching processing, and about 250° C. to about 700° C. for deposition processes (including PVD and CVD).
Various techniques have been employed in the art for reducing the intrinsic resistivity of pure aluminum nitride, which tends to be too high for efficient electrostatic chuck operation, such as on the order of 1013 ohm-cm. Such techniques include use of resistivity modifying agents to reduce the resistivity of the electrostatic chuck. While attempts at reducing the resistivity of aluminum nitride-based electrostatic chucks have been successful, it has been recognized that such low resistivities may undesirably result in leakage current, in which current flows away from the chucking surface supporting the semiconductor wafer. Such leakage current undesirably affects the chucking and de-chucking efficiency and performance. Accordingly, the art has sought to develop electrostatic chucks having reduced leakage current and improved chucking and de-chucking performance through the operational life of the electrostatic chuck.

Electrostatic chucks having barrier layer


Aspects of the invention can provide a method for driving an electro-optical device, an electro-optical device and electronic equipment that can solve the insufficient supply of the data current and current fluctuation. In the driving method, a data current can be applied to a plurality of pixels provided to a display panel unit with same value through the data line regardless of grayscale data. Upon supply of the data current, in the pixel, a transistor selected in reproduction can be turned on such that a drive current corresponding to the data current output from a driving transistor is supplied to an organic EL element, thereby emitting light. A light-off signal can be supplied to the pixel at predetermined timing such that the organic EL element emits light only in the light-emitting period computed based on the grayscale data. The pixel to which a constant data current can be supplied emits light at a luminance corresponding to the grayscale data by changing the light-emitting period corresponding to the grayscale data.

1. Field of Invention
Aspects of the invention can relate to a method for driving electro-optical device, an electro-optical device and electronic equipment.
2. Description of Related Art
Related art organic electro luminescence display devices (organic EL display device) can be referred to as electro-optical devices, and can include an electro-optical element made of an organic EL material. Related art electro-optical device can also have excellent characteristics of self-luminous, high luminance, high-angle-of-field, low profile, quick response, and low power consumption. Further, such devices can be made to be smaller and lighter with a peripheral driving circuit using a polysilicon TFT (Thin Film Transistor).
Incidentally, this kind of organic EL display device has a luminance variation between pixels. Thus, various kind of driving methods including a current program method are proposed. See, for example, U.S. Pat. No. 6,229,506 B1.

Method for driving electro-optical device, electro-optical device and electronic equipment


A flexible tonneau cover for trucks that is easily folded for storage or shipping. The tonneau cover has a collapsible peripheral frame, with supporting bows spanning the width of the frame. The bows include separable parts for storage or shipping and can be assembled and expanded to spread the frame.

This invention relates to a flexible tonneau cover for pick-up trucks. Tonneau covers are to serve the purposes of protecting the contents of a truck bed from the elements, as well as provide a more streamlined surface than just an open truck bed. A drawback to tonneau covers is that shipping them may be difficult due to their size and weight. Such covers can be bulky to ship because a frame is necessary to support the flexible cover and the frame is necessarily large to provide support over a pick-up truck bed.


A door release system including a capacitive circuit that includes a touch bar, a microprocessor within the touch bar programmed with noise-discrimination software to sense touching of the bar, and at least one micro-switch within the bar to function as a back-up that picks up movement of the bar to release the latch should the capacitive circuit fail. Optionally, a sign illuminated by LEDs and an antimicrobial coating/treatment may be applied to the bar. The system is intended for use on magnetically locked doors. The addition of the micro-switches that are actuatable by continued movement on the touch bar after the bar is initially touched provides a redundant access function initiated by other than the capacitive effect of human touch, which is expected to simplify use and ease accessibility for personnel with prosthetics or who may otherwise have their hands occupied.

A requirement of magnetically-locked exit doors is that the magnetic lock be deactivatable from within a building upon demand by a user desiring egress. A typical exit door is provided with a horizontal electromagnetic lock-deactivating bar mounted across the inner surface of the door and responsive in any of a wide variety of ways to pressure by a user. In the art, it is considered to be good design to provide two or more redundant deactivating systems to ensure that a door may be opened even if one of the systems malfunctions.
For example, U.S. Pat. No. 4,871,204 discloses a release system comprising a capacitive circuit, including a relay, that senses any touching of a fixed horizontal bar in a first user action, and a separate back-up micro-switch activatable circuit. The capacitive circuit relay, when engaged in response to the human touch sensor, includes means for opening the locking circuit for the electromagnetic lock. In the event of malfunction of the capacitance sensor system, egress can still be accomplished, in a second and separate user action. This is accomplished by pressing the push button switch, mounted on or near the bar, which activates the capacitive circuit relay.
A shortcoming of the disclosed system is that the capacitive sensor output signal can be corrupted by electronic noise, causing the door to become unlocked when not intended and potentially allowing ingress from the outside. A further shortcoming is that a second distinct user action is required to open the door if the capacitive sensor system fails. A user may not know of the push button switch, or a user may not remember the position of the push button switch or how the switch may be activated, especially in this system since the switch is concealed behind the push bar.
For another example, U.S. Pat. No. 5,969,440 discloses a release system comprising two electromechanical force transducer assemblies mounted within a moveable bar and responsive to translation of the bar. When a given amount of pressure is detected by either or both of the electromechanical force transducer assemblies, the door will be unlocked and can be subsequently opened. A back up switch is also located on the bar and will operate in a fail-safe manner (without power) to unlock the door in the event of a failure of one or both of the transducer assemblies upon detection of a greater amount of force being exerted upon the bar.
A shortcoming of the disclosed system is that activation of either or both of the transducers requires substantial force, for example, between 5 and 15 pounds of pressure, and operation of the back-up micro-switch requires not less than 15 pounds of pressure. The large force required to operate the back-up switch is needed to ensure that the pressure transducers come into play before the back-up switch is used. Forces in this high range may be beyond the capabilities of a user in a given situation. Further, the disclosed electromechanical force sensors use force sensing resistors whose sensitivity and output may change with aging of the sensors or of the associated actuating padding material.
In yet another example, U.S. Pat. No. 6,429,782 B2 discloses a door release system comprising a conductor forming part of a capacitor with variable capacitance dependent upon the proximity of a person, and a detector for sensing variation in the capacitance and for generating an output signal indicating proximity of the person relative to the conductor as the person's hand touches the release. The switch device further includes a mechanical switch arranged for actuation by a person gripping or pulling the door handle to additionally or alternatively indicate proximity of the person. The system includes an oscillator coupled to the conductor and a phase comparator. The variation in capacitance results in an associated change of frequency in the oscillator to produce a phase-modulated signal which is applied to the phase comparator to generate a signal representative of the change in frequency.
What is needed in the art is a door latch release system that includes a capacitive circuit including at least one capacitive sensor, a micro-processor programmed with noise-discrimination software to sense touching of the bar and a micro-switch, or switches, as back-up that picks up movement of the bar to release the door should the capacitive circuit be unresponsive.
It is a principal object of the present invention to increase the reliability of a door is release system by incorporating a back-up system that can redundantly release the door upon a natural and continued motion of the person opening the door.
It is a further object of the present invention to increase the reliability of a door release system by discriminating against spurious noise signals that can cause a capacitive switching system to open inadvertently or to be opened maliciously while also providing a back-up door release switch which is less sensitive to pounding on the exterior side of the door.


A portable therapeutic massage mat includes a base and a plurality of protrusions extending from the base. The protrusions may have a square pyramidal shape or other suitable shapes. The plurality of protrusions, the base, or the entire massage mat may be formed of a material that includes at least one thermochromic pigment. The material that includes the thermochromic pigment may be a thermoplastic elastomer. When a user sits or rests upon the portable massage mat for a time, local blood flow increases causing a rise in local body temperature which is exhibited by a color change of the portable massage mat, due to the thermochromic pigment. The increased local blood flow provides beneficial therapeutic effects such as reducing the appearance of cellulite, relieving minor aches and pain, and relieving minor muscle spasms.

Studies have shown that a significant percentage of women and some men may have cellulite and that cellulite is genetic and may become more noticeable with age or can be affected by diet, lack of exercise, hormonal changes and/or changes in weight. Cellulite is more commonly seen in the abdomen, buttocks and thighs, but can also be seen in other parts of the body. The cellulite, under the skin, gives the skin a non-uniform appearance sometimes likened to the appearance of cottage cheese. It is a general notion that the dimpled appearance of skin due to the presence of cellulite is unbecoming.
It is understood that the appearance of cellulite can be temporarily reduced or eliminated by mechanical massage which has the effect of stimulating local circulation to the area and promoting lymphatic drainage of excess fluids present in fat cells. Both of these effects of mechanical massage may lead to the temporary appearance of a reduction in the appearance of cellulite.
With this understanding, a number of approaches have been proposed to temporarily reduce the appearance of cellulite. For example, one approach may involve a user using creams such as those containing caffeine or aminophylline to temporarily reduce the appearance of cellulite. However, such creams are messy, with no immediate results (in fact, most see no reduction in the appearance of cellulite for 4 to 6 weeks with daily use), maintenance is difficult to achieve and regular use is hard to maintain, and even when results are good, the recurring costs can be quite expensive. Furthermore, many of the lotions and creams that are applied topically can require multiple applications per week, can require the use of drugs or chemicals, can be irritating to the skin and must be used consistently over time to achieve then maintain desirable results.
As another example, hand-held therapeutic massaging devices designed to temporarily reduce the appearance of cellulite require active use and significant time requirements on the part of the user. Furthermore, undergoing such services/procedures, such as those used in endermologie or cellulaze treatments, requires the user to schedule an appointment to a specialist's office and have no 'at home' utility. Many office procedures may offer similar results in reducing the appearance of cellulite. However, these office procedures require multiple visits to a specialist's office, which are costly and usually more invasive and time consuming, all for a temporary result. In addition, the more invasive the procedure, the more technical skill required by the medical provider and the more dependent the results are on the technician. These more invasive procedures have risks of bruising, bad results and can be painful.
Various mechanical devices that provide massaging or other physical treatment of the skin are also known. Various other chemical treatments and radiation treatments are also known.
U.S. Pat. No. 5,402,545 (Jolley) teaches an orthopedic seat cushion for permitting free circulation and protecting the user's coccyx. A cushion with numerous protrusions is disclosed.
U.S. Pat. No. 5,628,079 (Kizemchuk et al.) is directed to a seat cushion with projections. The seat cushion has a flexible substrate and pads. The pads have a pattern of projections thereon in a spaced, parallel relationship and it is reported that the cushion provides a massage of a person's buttocks or thighs to help alleviate cellulite.
U.S. Pat. No. 5,250,067 (Gelfer et al.) is directed to a body treatment pad having multiple sharpened skin-penetration protuberances. The pad includes a flexible backing sheet having a multiplicity of similarly constructed rigid blocks at spaced points along the sheet surface. Each block has at least one tapered protuberance extending away from the sheet. When the pad is held under pressure against person's body, the sharpened protuberances act as acupuncture elements to stimulate nerve endings under the skin, thereby increasing the blood circulation and relieving pain.
U.S. Pat. No. 5,134,735 (Rose) is directed to a mattress cushion with multiple zones. Each of the cushion's three separate zones has a different compression modulus such that when a person presses down on the zones, support proportional to the body's weight is achieved. U.S. Design Pat. No. 294,212 (Sias et al.) is directed to a design of a seating pad having upwardly extending protuberances. U.S. Pat. No. 4,614,000 (Mayer) is directed to patient undersheet for preventing bed sores that utilizes upwardly extending protuberances. U.S. Pat. No. 4,829,987 (Stewart) is directed a method of treating the human body with a mineral solution and a body wrap to aid in the temporary reduction of cellulite. U.S. Pat. No. 3,744,483 (Picolin) is directed to a walking mat with a base and an upper undulating piece and with upwardly extending protuberances.
As these examples illustrate, prior approaches to temporarily reducing the appearance of cellulite, while potentially effective, create user compliance issues that undermine overall success, including costs, ease of use, portability, allowance for changes in the user's body positioning, size of person, size of chair to accommodate placement of mat, and performance. Consequently, there is ample room for innovations and improvements.

Portable therapeutic mat with thermochromic properties

SANKO TEKSTIL ISLETMELERI SAN. VE TIC. A.S.


A cholesteric liquid crystal composition containing at least one esterified product selected from the group consisting of (1) an esterified product of a hydrolysate of (A) a γ-oryzanol and (B1) a carboxylic acid compound, (2) an esterified product of a hydrogenated product of a hydrolysate of (A) a γ-oryzanol and (B2) a carboxylic acid compound, and (3) an esterified product of a hydrogenated product of (A) a γ-oryzanol and (B3) a carboxylic acid compound. The γ-oryzanol (A) is a mixture containing at least one ferulate ester of a vegetable sterol and at least one ferulate ester of a triterpene alcohol, and the hydrolysate of the γ-oryzanol (A) is a mixture containing at least one vegetable sterol and at least one triterpene alcohol.

1. Field of the Invention
The present invention relates to a cholesteric liquid crystal composition that reflects light having a particular wavelength range around room temperature and body temperature, and a use thereof.
2. Related Art
A cholesteric liquid crystal molecule has a helical structure in a liquid crystal state. Accordingly, upon irradiating a cholesteric liquid crystal phase with light, the liquid crystal phase reflects circularly polarized light having a specific wavelength range corresponding to the rotation direction and the pitch length of the helical structure of the liquid crystal molecule. For example, upon irradiating with visible light, the liquid crystal phase selectively reflects light having a wavelength of blue, green, yellow and red corresponding to the pitch length of the liquid crystal. The color of the reflected light has viewing angle dependency, i.e., changes depending on the viewing angle, which is different from a pigment or dye, which exhibits color by absorption of light. The cholesteric liquid crystal can be controlled in pitch length by the temperature and the species of the compound, and thus can selectively reflect light not only in the visible range but also in a near infrared range or an ultraviolet range.
Materials that selectively reflect light of various wavelengths within a wide wavelength range have been provided by utilizing the characteristics of the cholesteric liquid crystal. Examples of the materials include a liquid crystal pigment, a paint, a spray ink, a printing ink, cosmetics, an anticounterfeit printed matter and an ornament. Such materials have been proposed as an optical film, such as a polarizing plate, a compensation plate and a color filter, for an optical device, such as a liquid crystal display device and a holography device. The cholesteric liquid crystal pigment, which has been known in the art, includes a cholesteric liquid crystal polymer in a flake form and a microencapsulated cholesteric liquid crystal. JP-A-2001-311079 discloses manufacturing method of a microencapsulated cholesteric liquid crystal. Examples of the purpose thereof include a paint for an automobile and cosmetics.
An animal-derived material (cholesterol) extracted mainly from wool wax has been used as a raw material for the cholesteric liquid crystal (cholesteric material), and in recent years, a vegetable-derived material is receiving attention in view of care for the environment and the human body. The vegetable-derived material is a component extracted from vegetable seeds or various parts of vegetables, and can be obtained, for example, from rice bran, rice bran oil, soybean, wheat, corn, palm, cotton seeds, coleseed or the like. Examples of a vegetable-derived material that exhibits liquid crystallinity include vegetable cholesterol, which is contained in soybean in a large proportion, and a triterpene alcohol derivative, which is obtained from rice bran oil.
DD 252,884 discloses that a sitosterol derivative has a cholesteric phase in a region of 150° C. or more, and a composition thereof has a cholesteric phase around room temperature. The major component of the composition is a cholesterol derivative, to which the characteristics of the cholesterol derivative, i.e., exhibition of a cholesteric phase around room temperature, is reflected.
JP-A-3-99094 discloses that esterified products of triterpene alcohols have a cholesteric phase, but all the esterified products disclosed have a narrow region where a cholesteric phase is exhibited, and no compound is disclosed that has a cholesteric phase within a wide range around room temperature. The triterpene alcohols used therein are contained as mixtures in naturally-derived materials, and it is difficult to isolate them by extraction for industrial use.
JP-T-2004-504291 (the term "JP-T" as used herein means a published Japanese translation of a PCT patent application) discloses, as a vegetable unsaponifiable material, an ester of sterol, stanol or triterpene alcohol with a long-chain fatty acid. The compound is used in such purposes as cosmetics and pharmaceuticals, but JP-T-2004-504291 does not disclose or suggest liquid crystallinity.
JP-A-2006-176422 discloses that an ester of vegetable sterol or triterpene alcohol with a long-chain fatty acid, as a sterol ester obtained from rice bran, is used in such purposes as cosmetics and pharmaceuticals, but JP-A-2006-176422 does not disclose or suggest liquid crystallinity.
JP-A-5-310526 discloses γ-oryzanol, which is an ester of sterol or triterpene alcohol with ferulic acid, and JP-A-57-62212 discloses an esterified product of triterpene alcohol with hydroxybenzoic acid. However, these documents do not disclose or suggest liquid crystallinity.
In the case where a cholesteric material obtained from a vegetable-derived material is used in the cosmetic field, and particularly applied to the human lips and skin, such a material is demanded that exhibits cholesteric reflected color in a temperature range around room temperature or body temperature. Red to purple, preferably red to yellow colors are required to be developed in a temperature range in the vicinity of 0 to 60° C., particularly preferably 20 to 40° C. Accordingly, a cholesteric liquid crystal material is demanded to be controlled in color range with respect to temperature when the material is applied to the cosmetic field for exhibiting esthetic effect thereby.


A device for printing a succession of sheets, includes a platen press for depositing colored or metalized film on each sheet by stamping between a stationary platen and a movable platen. A heating element brings a stamping tool integral with the stationary platen to a given temperature for a stamping operation. The heating element is displaced between an operating position, which is between the stationary platen and each stamping tool associated with that platen, and a maintenance position in which the heating element is outside the platen press.

The present invention relates to a device that allows a succession of elements in the form of sheets to be printed by hot stamping.
The invention is applied in a particularly advantageous but not exclusive manner in the field of manufacturing packaging intended for the luxury goods industry.
It is known to print text and/or patterns using stamping, in other words to deposit colored or metalized film coming from one or more stamping foils, commonly known as metalized strips, on a support in the form of a sheet by being pressed against it. In the industry, such a transfer operation is traditionally performed by means of a vertical platen press, in which each printing support and the relevant stamping foils are pressed together between two parallel platens, one of which is stationary while the other is mounted so that it can move by being displaced in a vertical back-and-forth motion.
In the case of hot stamping, the transfer of the film requires heat to be applied as well as pressure. For this reason, a heating element is usually inserted between the stationary platen and the stamping tools which are associated with the latter. Such a heating element generally takes the form of a heating plate, one face of which is covered with an insulating material intended to serve as an interface with the plate, while the other face is intended to extend behind the stamping tools.
In practice, the heating element is integrally connected to the stationary platen by means of multiple fastening screws which are fitted from the inside of the platen press. This means in practice that each of them passes through the heating element before being screwed into an internal screwthread formed in an appropriate manner in the platen.
However, this type of arrangement has the disadvantage of making it particularly difficult to access the heating element, which has the consequence of significantly complicating maintenance and repair work. Indeed, in order to fit and remove the fastening screws, someone needs to put their arms between the platens of the press, which proves to be extremely impractical. Moreover, in order to reach the fastening screws furthest away from the side on which the operator stands, some peripheral units placed directly upstream and downstream from the platen press often need to be removed. Lastly, the heating element needs to be supported by hand the whole time that units are being extracted or inserted into the platen press.
The technical problem which is to be overcome by the subject of the present invention is also to provide a device for printing a succession of elements in the form of sheets, comprising a platen press capable of depositing colored or metalized film coming from at least one stamping foil on each sheet by stamping between a stationary platen and a movable platen, and a heating element capable of bringing any stamping tool integral with the stationary platen to a given temperature so that the stamping operation takes place in a hot environment within the platen press, which printing device would allow the problems from the prior art to be avoided, in particular by affording much easier maintenance.


In a processor employing separate instruction and data caches in at least one cache hierarchy level, a cache control instruction forces modified data within the separate data cache to a lower cache hierarchy level. An existing cache access attribute is employed to distinguish between occasions when the data must be written all the way to main memory and occasions when the data need only be written to a cache hierarchy level from which fetches are made to the separate instruction cache. Thus, the separate instruction and data caches may be made coherent without writing all the way to main memory, but the ability to write modified data to main memory whenever necessary is preserved. Utilization of the existing attribute avoids increasing processor complexity and/or resources.

1. Technical Field
The present invention relates in general to cache coherency in data processing systems and in particular to efficiently maintaining cache coherency in data processing systems having multiple caches of the same and/or different levels. Still more particularly, the present invention relates to an enhanced cache store protocol for forwarding store updates only as far as necessary to assure cache consistency.
2. Description of the Related Art
Current reduced instruction set computing (RISC) processors typically contain both instruction and data level one caches. Utilizing separate level one caches is necessary in view of the extreme bandwidth required in contemporary processors. Instruction fetches and data references in superscalar processors may easily exceed more than one cache access per cycle. Therefore, instruction and data references are issued to separate caches, one for data and one for instructions. Each level one cache is designed for access every cycle.
One problem with separate level one caches for data and instructions is that periodically a processor will modify data in the data cache which is determined to actually comprise instructions to be executed later. This may occur, for example, when a loader program resolves code linkages after loading the code into memory. The processor may have already fetched this data into the instruction cache, before the data was modified. However, most RISC processors do not include any mechanism for maintaining level one cache coherency; that is, changes in one are not automatically reflected in the other. Therefore, software executing in the processor is required to provide a mechanism for handling such situations. The problem is usually addressed by flushing any instructions in the data cache which have been modified and invalidating the same addresses which may be in the instruction cache. This is done for any lines which may have been changed (typically all of the lines within a program) one page at a time.
Most superscalar processors having separate level one caches support an instruction for forcing all modified data within a given cache block out of the level one data cache. In PowerPC.TM. processors, this instruction is a data cache block store (dcbst) instruction. When a dcbst instruction is executed, the effective address is computed, translated, and checked for protection violations. If the target cache block for this instruction does not contain modified data, the cache block is left unchanged and a clean operation is broadcast onto the bus. If modified (dirty) data is associated with the cache block, however, the processor pushes the modified data out of the data cache. All bytes in the cache block are written to main memory and the cache block is flagged "exclusive," indicating that the cache contains data at that address which is valid data shared with system memory, but other caches may contain incongruent data at the same address.
Other RISC processors support equivalent instructions for similar operations. Such instructions, however, are also used by programmers who wish to make the results of a modified line in the cache immediately visible outside the processor. This may be useful, for example, in making a graphics update to a memory mapped graphics adapter. Thus, the instruction provided to solve cache coherency problems by forcing data all the way to memory may also be used to force data to an I/O device. These disparate uses, however, are to some degree inconsistent in their objectives. Use of the dcbst or equivalent instruction for cache coherency need not write the data all the way to the lowest level in the cache hierarchy; merely writing the data to a point from which data fetched to the instruction cache derives would be sufficient.
It would be advantageous, therefore, to provide a mechanism for distinguishing dcbst or equivalent instructions intended to provide cache coherency from similar instructions intended to disseminate results of a modified cache line. It would further be desirable if mechanism did not add significantly to the operational complexity or resource requirements of the processor.

Cache block store instruction operations where cache coherency is achieved without writing all the way back to main memory

International Business Machines Corporation


A method of determining a network topology based on Spanning-tree-Algorithm-designated ports is disclosed. A first Spanning-tree-Algorithm-designated port that is associated with a network interface of a first network device is determined. A second Spanning-tree-Algorithm-designated port that is associated with a network interface of a second network device is determined. Based on the first designated port and the second designated port, it is determined whether the network interface of the first network device is connected to the network interface of the second network device.

The approaches described in this section could be pursued, but are not necessarily approaches that previously have been conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Computers and other devices equipped with network interface hardware may be connected together to form a network that allows the devices to communicate data with each other. An example of such a network is a local area network (LAN). A LAN may be composed of several different LAN segments. All devices connected to a given LAN segment receive all of the data communicated through the given LAN segment.
For example, a LAN segment's data traffic may be transmitted over a single cable that functions as a bus. In such a configuration, all devices connected to the single cable receive all of the data communicated over the single cable, although individual devices may implement filters to selectively ignore some of the received data.
For another example, a LAN segment's data traffic may be transmitted over multiple cables that are interconnected through one or more network hubs. When a network hub receives data through a cable that is connected to one of the network hub's network interfaces, the network hub repeats the data through all of the other cables that are connected to the network hub's other network interfaces. Every device that is connected to one of the other cables receives the data. Like a single cable, the network hub operates at the physical layer of the Open Systems Interconnect (OSI) model. Regardless of whether a particular LAN segment's data traffic is transmitted over a single cable, a set of cables interconnected through one or more network hubs, or through wireless media, every device that is "on" the particular LAN segment receives all of the data that is communicated over the LAN segment.
Two or more LAN segments may be interconnected through a network bridge. Unlike a network hub, which operates at the physical layer of the OSI model, a network bridge operates at the data link layer of the OSI model. A network hub merely repeats received data through all of the network hub's network interfaces other than the network interface on which the data was received. In contrast, a network bridge, in response to receiving data through a cable that is connected to one of the network bridge's network interfaces, selects zero or more of the network bridge's network interfaces through which the data should be transmitted. Each of the network bridge's network interfaces may be connected to a different LAN segment.
For each network frame that the network bridge receives, the network bridge makes this selection based on data link layer address information, such as Media Access Control (MAC) address information, that is indicated within the network frame. For example, based on a destination MAC address indicated in a given network frame, a network bridge may determine that the network frame should be transmitted through a particular one of several of the network bridge's network interfaces in order to send the network frame over a LAN segment that forms part of the route to the network frame's ultimate destination. Another network bridge that is connected to the same LAN segment may receive the network frame and select yet another LAN segment over which the network frame should be transmitted. Thus, a network bridge may interconnect multiple LAN segments, and a LAN segment may interconnect multiple network bridges.
The data link layer topology, or "Layer 2" topology, of a LAN indicates how a LAN's bridges are connected to each other. In other words, a LAN's data link layer topology indicates, for each LAN segment in a LAN, which network bridges are connected to the LAN segment. Network hubs, which may comprise part of a LAN segment, do not need to be indicated distinctly from a LAN segment in a data link layer topology, because, as described above, network hubs operate at the physical layer rather than the data link layer. The data link layer topology of a LAN is a valuable aid in analyzing and configuring the LAN.
While the data link layer topology of a small LAN with few network bridges and LAN segments may be determined manually with reasonable effort, manually determining the data link layer topology of a large LAN with many network bridges and LAN segments can be extremely difficult. The dynamic nature of many LANs compounds the complexity of such a determination. Over time, the data link layer topology of a LAN can change, due to the addition, removal, reconfiguration, or failure of network devices and network media.
To determine the data link layer topology of large, dynamic LANs, several approaches for automatically calculating a LAN's data link layer topology have been devised. Cisco Systems, Inc. developed the Cisco Discovery Protocol (CDP). A particular network bridge that is configured to use CDP can automatically discover other network bridges that are connected to the same LAN segment as the particular network bridge, provided that the other network bridges are also configured to use CDP. Using the information discovered through CDP, the data link layer topology of a LAN may be determined if all of the LAN's network bridges are configured to use CDP. This CDP-based approach was implemented in Cisco Systems, Inc.'s CiscoWorks 2000 product.
While the CDP-based approach is effective in determining the data link layer topology of a LAN in which there are no network bridges that are unable to use CDP, the CDP-based approach may fail to determine the complete data link layer topology of a LAN in which there are one or more network bridges that are not CDP-enabled. Unfortunately, many existing LANs contain network bridges that are not CDP-enabled.
Another approach to automatically determining the data link layer topology of large, dynamic LANs may be called the MAC-based approach. The MAC-based approach takes advantage of MAC address information contained in Management Information Bases (MIBs) to determine a LAN's data link layer topology. MIBs are described in the Internet Engineering Task Force (IETF) Request For Comments (RFC) 1156 and in IETF RFC 1213. A specific Bridge MIB, described in IETF RFC 1493, specifies an object named "dot1dTpFdbTable"; "dot1d" refers to the Institute of Electrical and Electronics Engineers (IEEE) 802.1d standard.
Each network bridge maintains a dot1dTpFdbTable object. The dot1dTpFdbTable object contains information about unicast entries for which the network bridge has forwarding or filtering information. The network bridge uses such entries to determine how to propagate a received network frame. Each dot1dTpFdbTable object is an collection of one or more "dot1dTpFdbEntry" objects.
Each dot1dTpFdbEntry object contains a "dot1dTpFdbAddress" object and an associated "dot1dTpFdbPort" object. The value of a dot1dTpFdbAddress object is a MAC address, and the value of a dot1dTpFdbPort object identifies one of the network bridge's network interfaces. After receiving a network frame, a network bridge transmits the network frame through the network interface associated with the network frame's destination MAC address.
In order to determine whether a first network bridge's network interface and a second network bridge's network interface are connected to the same LAN segment, the MAC-based approach obtains all of the values of the dot1dTpFdbAddress and dot1dTpFdbPort objects maintained by the first network bridge, and all of the values of the dot1dTpFdbAddress and dot1dTpFdbPort objects maintained by the second network bridge. Based on these values, the MAC-based approach determines whether any of the obtained MAC addresses are associated with both the first network bridge's network interface and the second network bridge's network interface. If at least one of the MAC addresses is associated with both of the network interfaces, then the network interfaces are not connected to the same LAN segment. If none of the MAC addresses is associated with both of the network interfaces, then the network interfaces are connected to the same LAN segment.
Therefore, in order to determine the data link layer connectivity between just two network bridges, the MAC-based approach requires values of all of the dot1dTpFdbAddress and dot1dTpFdbPort objects maintained by the first network bridge, and values of all of the dot1dTpFdbAddress and dot1dTpFdbPort objects maintained by the second network bridge. In LANs that contain many network devices, each network bridge maintains many of such objects. Obtaining many MAC addresses and associated network interface identities can take a substantial amount of time and use a substantial amount of bandwidth. From a practical standpoint, the MAC-based approach lacks scalability.
Based on the foregoing, there is a clear need for a scalable method of automatically determining the data link layer topology of a LAN that contains one or more network bridges that are not CDP-enabled.

Method and apparatus for determining a network topology based on Spanning-tree-Algorithm-designated ports


The present invention relates to an electronic system comprising an electronic system comprising an electromechanical microsystem and a hermetic box encapsulating said microsystem. The box includes a fastening plane. The electromechanical microsystem includes a sensitive part and at least two beams connecting the sensitive part to the fastening plane. The beams are thermally coupled to the sensitive part and are electrically coupled to one another. The system further includes a thermal regulator of the electromechanical microsystem including an electrical circuit including at least two ends connected to the beams, and a circuit controller able to generate an electrical current in the electrical circuit to modify the temperature of the sensitive part.

In a known manner, an electromechanical microsystem is a microsystem comprising one or several elements that use electricity as power source, in order to perform a sensor and/or actuator function with at least one structure having micrometric dimensions, and the function of which is partially performed by the form of said structure. The term electromechanical microsystem is shortened using the acronym MEMS.
To see to the proper operation of a resonant electromechanical microsystem, the latter is generally mounted in a hermetic box under vacuum, for example made from a ceramic material. This box includes electrical contacts necessary to implement the transmission of data and optionally electricity between the electromechanical microsystem and an outside system.
Such a box is in particular described in document FR 2,958,451.
Furthermore, to provide the stable attachment of the electromechanical microsystem in the box while preserving the performance of the microsystem, it is known from document FR 2,966,813 to use flexible beams, also called decoupling arms, connecting the microsystem to the box. These decoupling arms, given their flexible nature, make it possible to absorb the differential expansions between the MEMS system and the box.
An electromechanical microsystem may for example have an actuator or a sensor, in particular an inertial sensor or an oscillator.
It is known that such an electromechanical microsystem has, during operation, a high sensitivity to outside temperature variations. Thus, it is often necessary to provide thermal control of the electromechanical microsystem in order to guarantee the homogeneity of the precision of its measurements or its actions. This is particularly the case when the electromechanical microsystem is used in so-called sensitive applications that may in particular be found in the aeronautic or aerospace field.
Traditionally, to implement thermal control of an electromechanical microsystem, the state of the art proposes the use of a Peltier model near a sensitive part of said microsystem. This module makes it possible either to heat or cool the sensitive part or the entire MEMS system. Another solution consists of adding a resistive element that, by Joule effect, makes it possible to heat the sensitive part or the entire MEMS system.
However, these solutions are not fully satisfactory.
In particular, in some cases, in light of constraints imposed in particular by the box, these solutions are implemented too far away from the MEMS system, such that a strong power is necessary to provide the proper operation of the assembly. In other cases, when these solutions are applied directly to the MEMS system, it is necessary for the operation of the assembly to add heterogeneous materials in this system. This generates carryover and differential expansion constraints, which deteriorates the long-term stability performance of the electromechanical microsystems. Furthermore, this adds additional steps during the production of these systems.

Electronic system comprising a microelectromechanical system and a box encapsulating this microelectromechanical system