It is provided a process for producing a purified essential oil excellent in safety and quality with high productivity from an essential oil comprising a harmful contaminant such as an agricultural chemical by simply and smoothly removing the contaminant with high removal rate without causing poor balance of flavor which the essential oil originally has, decrease of flavor strength and the like. It relates to a process for producing a purified essential oil by treating an essential oil comprising a contaminant with an active carbon to remove the contaminant and the removal rate of the contaminant is further improved by using an active carbon activated with a chemical, particularly an active carbon activated with zinc chloride, in the treatment, or by conducting the treatment at a low temperature of room temperature or lower, particularly at −25° C. to 5° C.

Essential oil (essential oil or natural essential oil) is an organic substance comprising a volatile odorant substance, extracted form a plant. The essential oil is obtained by treating a plant as a raw material with steam distillation, compression, extraction and the like, and recovering an oil comprising volatile odorant ingredients.
Of essential oils, citrus oil using citrus as a raw material is that monoterpene hydrocarbon which is a scent ingredient contained in citrus, and other terpene hydrocarbons are unstable to heat and light. For this reason, a so-called "cold press method" which recovers an oil by compressing citrus (particularly, coat of citrus) without applying heat is generally widely employed as a preparation method of the citrus oil.
The essential oil obtained above is generally used without modification as flavor or fragrance in various uses including cosmetic or food. However, in the case where troubles such as coloration, precipitation, turbidity, deteriorated odor and the like occurred by chemical change and alternation of ingredients contained in the essential oil during storage, the essential oil is purified and used. As the purification method in such a case, a method by distillation, a method of treating with a porous adsorbent, a cleaning treatment method, a filtration treatment method, and the like are employed. In the case of treating with a porous adsorbent, inorganic adsorbents such as active carbon, silica gel, alumina and zeolite, organic adsorbents such as styrene-divinylbenzene copolymer adsorbent and acryl absorbent, ion-exchange resins, porous glasses, and the like are used (see Non-Patent Document 1).
The essential oil is derived from natural plant, and should be inherently safe. However, a harmful contaminant such as agricultural chemicals, different from altered substances formed by chemical change and the like of the ingredients during storage and impurities originally contained in the essential oil, are sometimes detected, and the countermeasure becomes the problem.
The cause that agricultural chemicals are detected from the essential oil includes the case where agricultural chemicals used in the course of growth of a plant or used in the course of storage and distribution of the plant harvested are attached to and adsorbed on the plant as a raw material, and the agricultural chemicals move into the essential oil and remain therein, and the case where a plant absorbs agricultural chemicals not decomposed and accumulated in the soil among agricultural chemicals used in the past, from root, and the agricultural chemicals move into the essential oil and remain therein.
A method of conducting supercritical extraction of dried plant raw material, a method of conducting extraction treatment of a plant using a hydrophobic extractant, and the like are known as a method for producing a plant extract in which agricultural chemicals do not remain. However, those methods are a method that residual agricultural chemicals are avoided from being contained in a plant extract when preparing a plant extract by an extraction treatment of a plant. Therefore, the method cannot be applied to an essential oil, particularly citrus oil, in which scent ingredients are recovered by a compression method without using extraction.
A method wherein a plant extract, in which organic chlorine compound type agricultural chemicals remain therein, is dissolved in a mixed solution of a lower aliphatic alcohol and water in a volume ratio of from 10:90 to 80:20, and then the resulting solution is contacted with a porous adsorbing resin having a modal radius of pores of from 30 to 120 angstroms, the porous adsorbing resin comprising a three-dimensional copolymer of styrene and divinylbenzene and the like, thereby adsorbing residual agricultural chemicals in the solution on the adsorbing resin, and the plant extract is recovered from the treated solution is known as a method for removing agricultural chemicals remained in a plant extract (Patent Document 1). However, in the case of this method, effective ingredients having similar properties to those of residual agricultural chemicals, contained in the plant extract are adsorbed on the absorbing resin together with the residual agricultural chemicals. As a result, there is a problem that absorption loss is large, resulting in decrease in yield of a plant extract.
Furthermore, this method is a method for removing residual agricultural chemicals from a plant extract obtained by previously conducting an extraction treatment, such as a tea extract, and an essential oil obtained by compression without using extraction is not an intended material to be treated.
A method of cleaning an essential oil with an alkaline aqueous solution (Patent Document 2) and a method of treating an essential oil with a strong ion-exchange resin (Patent Document 3) are known as the method for removing residual agricultural chemicals from an essential oil.
However, the method of cleaning an essential oil with an alkaline aqueous solution has the problem that alkali-soluble flavor ingredients in the essential oil move into the alkaline aqueous solution, causing poor balance of flavor of the essential oil and considerable decrease in flavor strength, and the quality of the essential oil is greatly decreased.
The method of treating an essential oil with a strong ion-exchange resin has various problems that (a) because the strong ion-exchange resin is hydrophilic while the essential oil is hydrophobic, it is difficult to increase contact efficiency of the essential oil to the strong ion-exchange resin, and removal efficiency of residual agricultural chemicals is low; (b) there is a concern that water incorporates into the essential oil; (c) there is a concern that aldehydes which are important flavor ingredients in the essential oil are ethanolated, thereby inducing a polymerization reaction; (d) in the case where the strong ion-exchange resin is a cationic ion-exchange resin, loss of acidic flavor compounds in the essential oil occurs, on the other hand, in the case where the strong ion-exchange resin is an anionic ion-exchange resin, loss of alkaline flavor compounds in the essential oil occurs, and poor balance of flavor of the essential oil and decrease in flavor strength are easy to occur; and (e) there is a concern that dissolution of the strong ion-exchange resin occurs by the essential oil.
As described above, Non-Patent Document 1 describes that in the case where coloration, precipitation, turbidity, deteriorated odor and the like occurred by chemical change and alternation of ingredients contained in the essential oil during storage, the essential oil is purified with an adsorbent such as active carbon, thereby improving flavor. However, Non-Patent Document 1 does not describe the preparation of an essential oil having excellent safety, free of contaminant such as agricultural chemicals by treating an essential oil contaminated with a contaminant such as agricultural chemicals with active carbon.
Under the above circumstances, development of a method capable of producing a purified essential oil having excellent safety and high quality with good productivity by smoothly removing a contaminant such as agricultural chemicals contained in the essential oil in a simple operation while maintaining good balance of flavor which an essential oil originally has and flavor strength without causing loss and deterioration of flavor ingredients contained in the essential oil is being demanded.

Process for producing purified essential oil


Methods for generating a query input string include sorting a first input relation and a second input relation in order from the first relation to the second relation. The second input relation is concatenated to the first input relation, and the concatenated input relations are stored in a single string.

Pushing data-intensive computation down to a data management layer is one issue to fast data access and reduced data transfer. Integrating applications and data management have been attempted by, for example, running database programs including stored procedures on a server-side but outside a query engine, or performing computations through the use of user-defined functions (UDFs) executed in a query processing environment.

Hewlett Packard Enterprise Development LP


Piperidine compounds of formula II: ##STR1## that exhibit anticholinesterase activity and are effective in treating dementia.

1. Field of the Invention
The present invention relates to a novel quinoline derivative and a salt thereof possessing a superior anti-acetylcholinesterase activity, an intermediate for the preparation of the quinoline derivative and a salt thereof, and a pharmaceutical composition comprising these compounds.
2. Description of the Background
Senile dementia is broadly classified into the cerebral vascular disorder type and the Alzheimer type. Even though causes of Alzheimer type senile dementia have still to be elucidated, a number of attempts have been undertaken to treat or cure the disease by the administration of cholinergic drugs, since the theory of the cholinergic effects was proposed. For example, there is a report on the study of curing senile dementia by the use of physostigmine which is a typical acetylcholinesterase inhibitor [Neurology, 8, 397 (1978)]. Japanese Patent Laid-open (Kokai) Nos. 148154/1986, 141980/1988, 166881/1988, 73/1989, 250353/1989, 167267/1990, J. Medicinal Chemistry, 31, 1278 (1988), and J. Medicinal Chemistry, 32, 1805 (1989) report about anti-acetylcholinesterase effects of aminoacridine derivatives, claiming the effectiveness of the compounds in the curing of senile dementia. Summers et al. report the effectiveness of 9-amino-1,2,3,4-tetrahydro-acridine (Tacrine) and lecithin in the improvement in symptoms of senile dementia patients of Alzheimer type [The New England Journal of Medicine, 315, 1241 (1986)].
These known acetylcholinesterase inhibitors, however, do not exhibit sufficient curative effects and are accompanied by side effects such as liver disorders and the like.
The development of a compound useful as a medicine for curing dementia, which possesses an excellent anti-acetylcholinesterase effect with a least side effects, has therefore been desired.
In view of this situation, the present inventors synthesized various compounds and studied their pharmaceutical effects, and found that novel quinoline derivatives represented by the following formula (I) or their salts and novel piperidine derivatives represented by the following formula (II) or their salts exhibited excellent anti-acetylcholinesterase effects and were effective for curing dementia such as amnesic syndrome. Such a finding has led to the completion of this invention.

Piperidine compounds having anti-acetylcholinesterase activity


A window includes a window frame and a screen mounting assembly. The window frame is formed with two rail slots. The screen mounting assembly is adapted to be connected to a window screen and includes a roller unit, a sliding unit and an interconnecting unit. The roller unit includes a roller seat. The sliding unit is slidable along the rail slots and defines an engaging groove. The interconnecting unit is operable between a disengaging state where the interconnecting unit is connected to the roller seat, and an engaging state where the interconnecting unit is separated from the roller seat and inserted into the engaging groove so as to engage the sliding unit, such that movement of the sliding unit along the rail slots results in winding and unwinding of the window screen.

A conventional window 1 (see FIG. 1), which is disclosed in Taiwanese Patent No. M406090, includes a screen mounting assembly 20, a window frame 11 and a frame member 12. The screen mounting assembly 20 is coupled to the window frame 11, and includes a roller unit 210 connected to one end of a window screen 300 for the window screen 300 to be wound thereon. The frame member 12 is connected to an opposite end of the window screen 300 and is slidable on the window frame 11. Therefore, sliding movement of the frame member 12 will result in winding and unwinding of the window screen 30.
When the window screen 300 has to be replaced, the screen mounting assembly 20 must be uncoupled from the window frame 11 and the window screen 300 must be disconnected from the frame member 12. However, it is difficult for a customer or end user to disconnect the window screen 300 from the frame member 12. It is also not easy for the user to reconnect the window screen 300 to the frame member 12 after coupling the screen mounting assembly 20 back to the window frame 11.

Screen mounting assembly and window having the same


A food slicer 10 of the present invention contains a hollow body 12 having an inner wall 13 defining an interior 17 and an outer wall 15 for containment of a food product therein. A plurality of blades 32 extends across the interior 17 of the body thereby cutting a food product biased against the blades 32 into a plurality of portions.

The hot dog is eaten in almost every household and in many public events. It is one of the main food offerings in many entertainment activities such as baseball, for example. Often characterized as an "American tradition", the hot dog is a staple food product at picnics, sporting events, and campouts.
One of the concerns related to hot dogs or other cylindrical food products is the diameter and/or size of a normal bite-size piece. The American Academy of Pediatrics (AAP) recognizes that hot dogs or other round firm foods present common choking hazards. The August 1999 issue of Child Magazine indicates that hot dogs are among the top ten foods most likely to cause choking in children. Additionally, it is estimated that 78% of choking injuries occur in children under four years old, according to studies completed at the Dupont Hospital for Children in Wilmington, Del. Oftentimes infants or young children simply do not grind or chew their food well and they may attempt to swallow it whole. The AAP therefore recommends that these types of foods be cut or chopped to reduce the bite size, and, that they be consumed by infants and young children under adult supervision.
It is also well recognized that children may be finicky eaters. It therefore would be an improvement in the art to provide a utensil that not only quickly slices the food product to reduce choking hazards, but also forms a shape attractive to young children.


An interconnect structure for a semiconductor device and its method of manufacture is provided. The interconnect structure includes a multi-layer structure having one or more stress-relief layers. In an embodiment, stress-relief layers are positioned between layers of electroplated copper or other conductive material. The stress-relief layer counteracts stress induced by the conductive material and helps prevent or reduce a pull-back void. For an interconnect structure using electroplated copper, the stress-relief layer may be formed by temporarily reducing the electroplating current, thereby causing a thin film of copper having a larger grain size to be formed between other layers of copper. The larger grain size typically exhibits more of a compressive stress than copper with a smaller grain size. The stress relief layer may also be formed of other materials, such as SIP-Cu, Ta, SiC, or the like.

In modern integrated circuits, minimum feature sizes, such as the channel length of field effect transistors, have reached the deep sub-micron range, thereby steadily increasing performance of these circuits in terms of speed and power consumption. As the size of the individual circuit elements is reduced, so is the available real estate for conductive interconnects in integrated circuits. Consequently, these interconnects have to be reduced to compensate for a reduced amount of available real estate and for an increased number of circuit elements provided per chip.
Generally, integrated circuits (ICs) comprise electronic components, such as transistors, capacitors, or the like, formed on a substrate. One or more metal layers are then formed over the electronic components to provide connections between the electronic components and to provide connections to external devices. The metal layers typically comprise an inter-layer dielectric (ILD) layer in which vias and interconnects are formed, usually with a single- or dual-damascene process.
As mentioned above, the trend in the semiconductor industry is towards the miniaturization or scaling of integrated circuits, in order to provide smaller ICs and improve performance, such as increased speed and decreased power consumption. While aluminum and aluminum alloys were most frequently used in the past for the material of conductive lines in integrated circuits, the current trend is to use copper for a conductive material because copper has better electrical characteristics than aluminum, such as decreased resistance, higher conductivity, and a higher melting point.
The change in the conductive line material and insulating materials of semiconductor devices has introduced new challenges in the manufacturing process. FIG. 1 illustrates a portion of a wafer 100 having an ideal interconnect structure. Generally, the wafer 100 comprises a substrate 110, which may have electronic components such as transistors, capacitors, or the like formed thereon, or may comprise a metallization layer. An etch stop layer 112 is formed on the substrate 110, and a dielectric layer 114 is formed on the etch stop layer 112. A trench 116 and via 118 are formed through the dielectric layer 114 and the etch stop layer 112. The trench 116 and the via 118 are typically lined with a barrier/adhesion layer 120 (such as tantalum nitride) and then filled with a conductive material (such as copper).
FIG. 2 illustrates a common problem that may occur with an interconnect structure such as that illustrated in FIG. 1. In particular, the conductive material used to fill the trench 116 and the via 118 may exert a tensile stress, causing the conductive material to pullback from the bottom of the via and creating a pullback void 210. The pullback void 210 may increase the contact resistance between the interconnect structure and the underlying electrical component, or even cause the device to fail. This is particularly a problem when using copper as the conductive material to fill the trench 116 and the via 118.
Accordingly, there is a need for an interconnect structure that allows for the use of a low resistance material, such as copper, and prevents or reduces the pullback void.

Multi-layer interconnect structure for semiconductor devices

Taiwan Semiconductor Manufacturing Company, Ltd.


A method for obtaining a quorum vote by a first node using a quorum cable, wherein the quorum cable comprises a first end connected to the first node and a second end connected to a second node, including determining whether the quorum cable is reserved by the second node using a remote reservation input (RRI) on the first end, if the quorum cable is not reserved by the second node asserting a local reservation input (LRI) on the first end by the first node, monitoring a local reservation output (LRO) on the first end by the first node to determine whether the LRO on the first end is asserted in response to asserting the LRI on the first end, and obtaining the quorum vote by the first node, if the LRO on the first end is asserted.

A cluster typically refers to a service delivery platform that includes a tightly coupled group of servers (i.e., nodes), storage devices, and software. Each node in the cluster is interconnected to at least one other node in the cluster. The nodes in the cluster are configured such that the cluster as a whole provides the ability to run failover, parallel, and/or scalable resources. Thus, clusters are useful for industries that require high availability of applications and services (e.g., telecommunications industry).
Further, each node is associated with a cluster and is configured to join the cluster it is associated with when the node is booted. However, if the cluster to which the node is configured to join is not present when the node is booted, then the node may attempt to create the specific cluster to which it is configured to join. In some situations, the cluster to which the node is to join is present but due to a communications failure between the node and the cluster, the node is not able to join the cluster and, thus, attempts to create the cluster. In this situation, the cluster may become partitioned resulting in multiple instances of the same cluster being created and executed. The operation of two instances of cluster is commonly referred to as "split-brain" and may result in data corruption, etc.
To solve the aforementioned problem, a node may only create a cluster if the node obtains a sufficient number of quorum votes to obtain a quorum. The quorum refers to the minimum number of quorum votes required to create a cluster, which is typically half the number of nodes in the cluster plus one. Further, each node in the cluster typically has one quorum vote. Thus, if a node attempting to form the cluster is connected to at least half of the other nodes in the cluster, then a quorum is reached and the cluster created.
While the aforementioned scheme is adequate for clusters containing a relatively large number of nodes, the scheme is not appropriate for two-node clusters or clusters that may easily degenerate into two-node clusters. For a two-node cluster, the quorum votes required for a two-node cluster is 2 (i.e., 2 (number of nodes in cluster)/2+1).) Therefore, I the case of two-node clusters, if one node fails, then the remaining operational node is not able to create a cluster because the remaining operation node will never be able to obtain a quorum of 2.
The aforementioned scheme has been modified to address two-node clusters. Specifically, a quorum device is connected to the cluster such that each node in the cluster is able to communicate with the quorum device. The purpose of the quorum device is to provide an additional quorum vote. Thus, the quorum vote provided by the quorum device allows a single node in the two-node cluster to create a cluster in the event that the other node is not operational or experiencing communication difficulty. More specifically, each node in the two-node cluster includes functionality to reserve the quorum device, and thereby obtain the quorum vote associated with the quorum device. The ability to reserve the quorum device also provides a means for indicating, to the other node in the two-node cluster, that the quorum vote associated with the quorum device is in use, thereby preventing the node that does not have the quorum vote associated with the quorum device from creating a new cluster.
Quorum devices are typically shared storage devices (such as SCSI disks) and are referred to a quorum disks. The quorum disk is connected to all nodes that have a potential of joining the cluster. The use of a quorum disk typically requires that the nodes in the cluster have the appropriate hardware and software for interacting with the quorum disk.

This patent is subject to a terminal disclaimer.

Method and apparatus for using a serial cable as a cluster quorum device


A method for the preparation of a T cell vaccine for the treatment of immunodeficient HIV-infected patients is described herein, based on the enrichment of autologous CD4-reactive CD8 T cells. Also described is a protocol for the implementation of T cell vaccination in immunodeficient HIV-infected, as well as a method of treatment, based on the T cell vaccine developed herein. Finally, kits for preparing the T cell vaccine as well as for implementing the protocol are also provided.

All publications mentioned throughout this application are fully incorporated herein by reference, including all references cited therein. A full list of these publications is included at the end of the specification, immediately preceding the claims.
The hallmark of HIV infection and the eventual cause of AIDS is the progressive destruction of the CD4 T cell population. The in vitro cytopathic effects of HIV, with the CD4 molecule as its receptor and the gp120 molecule of the HIV envelope as its ligand, have led to the notion that HIV is the direct cause for the destruction of the CD4 T cell population [Lifson, J D. et al. (1986) Science 232:1123-1126; Casella, C R. et al. (1997) Curr. Opin. Hematol. 4: 24-31; Gandhi, R T. et al. (1998) J. Exp. Med. 187:1113-1122]. The inventors and others have previously suggested that additional mechanisms must account for the CD4 T cell decline during HIV infection [Grossman, Z. et al. (1993) Clin. Immunol. Immunopathol. 69: 1-13; Anderson, R W. et al. (1998) JAIDS 17: 245-252; Margolick, J B. et al. (1995) Nat. Med. 1:674-680; Quibin, L. et al. (2001) JAIDS 27:389-397] since the number of HIV infected cells at any stage of the infection is too small to account for the massive destruction of CD4 cells. One of the possible mechanisms that have been suggested is the killing of CD4 T cells by autologous CD8 T cells, with the CD4 molecules as self-antigens and targets for this autoimmune activity [Israël-Biet, D. et al. (1990) Clin. Exp. Immunol. 81:18-24; Zarling, J M. et al. (1992) J. Immunol. 144:2992-2998; Caporossi, A P. et al. (1998) Virol. Immunol. 11: 9-17]. Indeed, CD8 T cells of HIV-infected subjects were found to kill both HIV infected and non-infected CD4 T cells [Zarling (1992) id ibid.; Salemi, S. et al. (1995) J. Exp. Med. 81:2253-2257]. HIV infection could therefore be seen as an inducer for an autoimmune response against the CD4 molecule, leading to the destruction of the CD4 T-cell population [Lanzavecchia, A. (1995) J. Exp. Med. 181:1945-1948; Grant, M D. et al. (1994) JAIDS 7:571-579]. Such an autoimmune process could account for the persistence of CD4 T-cell leukopenia in patients despite complete or partial HIV viral suppression by highly active anti-retroviral treatment (HAART). Unfortunately, the proportion of such patients without sufficient immunological response is significant, reaching 50-60% in a number of reported series [Grabar, S. et al. (2000) Ann. Intern. Med. 133:410-410; Tarwater, P M. et al. (2001) JAIDS, 168-175; Pitrak, D L. et al. (2001) AIDS 15:1317-1319; Carcelane, G. et al. (2001) Curr. Opin. Immunol. 13:479-482; Kaufmann, G. R. et al. (2003) Arch. Intern. Med. 163:2187-95].
T cell vaccination (TCV) has been studied in experimental animals [Ben-Nun, A. et al. (1981) Nature 292:60-61; Holoshits, J. et al. (1983) J. Immunol. 131:2810-2813; Lider, O. et al. (1988) Science 239: 181-183] and lately has been used clinically to induce the down-regulation of autoimmune diseases such as multiple sclerosis [Van Laar, J M. et al. (1993) J. Autoimmunity 6:159-167; Haffler, D A. et al. (1992) Clin. Immunol. Immunopathol. 62: 307-317; Zhang, J. et al. (1993) Science 262: 1451-1454; Zhang, J. et al. (2000) J. Immunol. 164:4011-4017]. In all these instances, it was designed to raise an immune response in the host against the autologous effector cells that are causing the pathological changes responsible for the autoimmune disease. When successful, TCV has resulted in the suppression of these effector cells by the host response to the T cell vaccines, and the disease was either prevented or ameliorated. Based on the hypothesis that an autoimmune process takes place during HIV infection, Atlan and colleagues have suggested that autologous anti-CD4 T cells might be used as vaccines to down-regulate anti-CD4 autoimmunity in HIV-infected patients [Atlan, H. et al. (1993) Immunol. Today 14:200-202; Atlan, H. et al. (1994) Res. Immunol. 145: 165-183; Atlan, H. and Cohen, I R. (1996) Immunology of HIV Infection. New York: Plenum Press, Ch. 28].
Despite all the hypotheses that were raised in this respect, no studies have been done so far, at the clinical level, in order to verify the cellular origin of the immunodeficiency observed in HIV-infected individuals. The present study is the first of its kind in identifying one of the main causes of CD4+ T-cell depletion during HIV infection. The inventors investigated whether an autoimmune reaction towards CD4 is present in HIV infected patients, in comparison to controls. CD4-recognizing CD8 cells were found circulating and functional in HIV-infected patients, and such reactivity was evidenced in most of the HIV infected individuals. Thus, the present inventors propose and prove possible the generation and the use of inactivated CD4-specific CD8 cells as a tailor-made vaccine for treating HIV-induced immunodeficiency. In this context, the inventors went one step further and performed an open trial of the TCV developed herein in HIV-infected individuals. Results are summarized in Example 1 below. Based on the encouraging results of this study, the inventors developed a general outline for a T-cell vaccination protocol.
Thus, it is an object of the present invention to provide a method for preparing T cell vaccines tailored for immunodeficient patients, particularly when the immunodeficiency is consequent of HIV infection. The invention also provides a method of treatment of an auto-immune process induced by HIV infection. To a larger scale, the invention provides a T-cell vaccination protocol, based on the tailored-made T cell vaccines prepared from HIV-infected individuals.

Inactivated CD8+ T-cells for the treatment of HIV infection

Hadasit Medical Research Services and Dev. Ltd


A paraxial cloaking device provides a cloaking volume in which an item can be hid from view. A cloaking device includes an optical input receiving light rays and an optical output from which a continuous range of directions of the received light rays exit the paraxial cloaking device. The cloaking volume being disposed between the optical input and the optical output. For received light rays having incoming directions non-parallel to the reference optical axis up to a first angle, each of the received light rays exits the cloaking device substantially aligned with the respective received light ray and does not pass through the cloaking volume. The paraxial cloaking device has a unity magnification factor. In some instances, the paraxial cloaking device includes a phase matching element.

Optical spatial cloaking has captured the imagination of both the popular culture and scientific communities (see, e.g., Gbur, G. Invisibility physics: Past, present, and future. Progress in Optics 58, 65-114 (2013)). Seminal works in optical spatial cloaking includes work by Leonhardt (Leonhardt, U. Optical conformal mapping. Science 312, 1777-1780 (2006)) and Pendry, Schurig, and Smith (Pendry, J. B., Schurig, D. & Smith, D. R. Controlling electromagnetic fields. Science 312, 1780-1782 (2006)). These seminal works provide a theoretical framework to create a curved space for light waves, by carefully constructing materials in Cartesian space. This new field of research has been called 'transformation optics' (McCall, M. Transformation optics and cloaking Contemporary Physics 54, 273-286 (2013)). Experimental realization of such transformational optics has been difficult, due to the previously perceived need for artificial electric and magnetic materials (called 'metamaterials'), the narrow-band spectrum involved, infinite phase velocity (or negative index to compensate this), and anisotropy in the theory (Gbur, G. Invisibility physics: Past, present, and future. Progress in Optics 58, 65-114 (2013)). Nonetheless, inspired by transformation optics, there have been some advances in optical spatial cloaking. These advances include a two-dimensional microwave cloak (Schurig, D. et al. Metamaterial electromagnetic cloak at microwave frequencies. Science 314, 977-980 (2006)); a 'carpet cloak' that hides an object under a surface (Li, J. S. & Pendry, J. B. Hiding under the carpet: A new strategy for cloaking Physical Review Letters 101, 203901 (2008)); and even cloaking in time (Fridman, M., Farsi, A., Okawachi, Y. & Gaeta, A. L. Demonstration of temporal cloaking Nature 481, 62-65 (2012)), and (Lukens, J. M., Leaird, D. E. & Weiner, A. M. A temporal cloak at telecommunication data rate. Nature 498, 205-208 (2013)). A few groups have been able to cloak millimeter- to centimeter-sized objects as well, using birefringent materials (Zhang, B. L., Luo, Y. A., Liu, X. G. & Barbastathis, G. Macroscopic invisibility cloak for visible light. Physical Review Letters 106, 033901 (2011)), and (Chen, X. Z. et al. Macroscopic invisibility cloaking of visible light. Nature Communications 2, 176 (2011)).
To overcome the metamaterial requirements (in some implementations) and to extend cloaking to a broadband, visible regime for large objects, researchers have recently looked to ray optics for cloaking (see, e.g., Chen, H. et al. Ray-optics cloaking devices for large objects in incoherent natural light. Nature Communications 4, 2652 (2013); Zhai, T. R., Ren, X. B., Zhao, R. K., Zhou, J. & Liu, D. H. An effective broadband optical 'cloak' without metamaterials. Laser Physics Letters 10, 066002 (2013); and Howell, J. C., Howell, J. B. & Choi, J. S. Amplitude-only, passive, broadband, optical spatial cloaking of very large objects. Applied Optics 53, 1958-1963 (2014)). In these cloaks, the amplitude and direction of light fields are considered, as opposed to the full preservation of fields (amplitude and phase) of transformation optics. These designs have been able to cloak centimeter to meter-sized objects with commonly available optics. Yet, these schemes work only for unidirectional incident light, as they are not designed for continuous multidirectional cloaking, and can have non-unity magnifications. For off-axis, non-zero angles, the background images show distortion and positional shifts. This is particularly true if the background is far away from the cloaking device. In addition, as seen in FIG. 1 of Howell, J. C., Howell, J. B. & Choi, J. S. Amplitude-only, passive, broadband, optical spatial cloaking of very large objects. Applied Optics 53, 1958-1963 (2014), rays that propagate through the system, but go through the center at non-zero angles, can actually enter the cloaking region, effectively uncloaking the space.
Despite the advances in cloaking, a 3-D multidirectional cloak has been elusive. As shown by Wolf and Habashy (Wolf, E. & Habashy, T. Invisible bodies and uniqueness of the inverse scattering problem. Journal of Modern Optics 40, 785-792 (1993)) and Nachman (Nachman, A. I. Reconstructions from boundary measurements Annals of Mathematics 128, 531-576 (1988)), no isotropic cloaking scheme can hide an object from all viewing angles. Their work answered a question that stemmed from Devaney (Devaney, A. J. Nonuniqueness in inverse scattering problem. Journal of Mathematical Physics 19, 1526-1531 (1978)), who elegantly showed how to mathematically construct potentials that have zero scattering fields, and are hence invisible. Devaney's result, however, was for a finite number of discrete directions, and not for a continuous range of angles.


A system and a method are disclosed for performing a timing or signal propagation delay analysis on a circuit. The disclosure includes representing a drive logic stage as a representative linear circuit driven by a current source. The current source is represented as a function of a current at a constant value, a start time, a tail-start time, and a time constant of an equivalent capacitive circuit. Once the current source model is constructed, a logic stage can be analyzed for timing or signal propagation delay using conventional linear circuit analysis techniques. The disclosure also is applicable to resistance capacitance (“RC”) interconnect circuits using a current source model in which an RC load is represented as an effective capacitance and the current source for use in a linear analysis is constructed using an iterative approach.

1. Field of the Invention
The present invention generally relates to the field of circuit modeling, and more specifically, to gate delay models.
2. Description of the Relevant Art
To shorten design cycles, digital systems are often designed at a gate and/or cell level. In contrast to designing at a transistor level, gate or cell level design can significantly reduce costly design verification by precharacterizing gate and cell delays for static timing analysis. The cell delays and transitions are generally expressed empirically as a function of load capacitance and input signal transition time. However, with the emerging interconnect dominance, gate loads can no longer be modeled by purely capacitive loads for high performance digital circuits.
For digital IC technologies in general, and CMOS in particular, it is assumed that a load at an output of the gate has a negligible impact on the waveform behavior at a gate input. Therefore, digital circuit delay calculation along timing paths can be performed gate by gate or logic state by logic state for applications such as timing analysis. It should be noted that the gate-source and gate-drain capacitances are included as part of the gate characterization and, therefore, not considered during the partitioning process.
Delay calculation is performed for each logic gate/state input individually. It is assumed that all other gate inputs are set to logic values such that an input pin under consideration can cause a gate output to transition. The outputs that are expected from a delay calculator are the waveforms at the fan-outs, as a function of the waveform at the switching input pin.
There are two approaches to gate delay modeling, which have gained widespread acceptance. The first is empirically derived expressions or look-up tables for delay and output-signal transition as a function of load capacitance and input-signal transition time (k-factor equations), which is further described below. The second is a switch-resistor model comprised of a linear resistor and a step function of voltage, also described below. Both methods are empirically based, since even the second method requires empirical fitting to approximate the resistance value.
Switch resistor models have an advantage that their coupling with an RC interconnect is inherently modeled. That is, the resistance model is able to capture the interaction of the gate's output resistance and the RC load. Timing analysis tools such as TV and Crystal were developed using switch-resistor models to analyze the transistor level circuit descriptions. The main difficulty with these approaches is calculating a single linear resistor, which captures the switching behavior of a CMOS gate. Recognizing that this resistance is a function of the gate's input signal transition. Recognizing that this resistance is a function of the gate's input signal transition time and output load, in a single output resistance for the gate is empirically derived. That is, the resistance is calculated as the average output impedance over a range of input signal transition times and output loads.
When the load is purely capacitive, one can completely precharacterize a gate's delay and output signal behavior as a function of input signal transition time, ttr-in, and load capacitance, CL. The experimental data for delay, td, and gate-output waveform transition time, ttr-out, are generally fitted to k-factor equations:td=k(ttr-in′CL)ttr-out=k′(ttr-in′CL)where k and k′ are empirically fitted functions, and the delay and transition times are defined as shown in FIG. 1. Note that the waveforms are simplified as saturated ramps by fitting a line through two predefined characterization points. With this approximation it is possible to represent the waveshape with a single number, the transition time.
Some methodologies use more than two points to characterize the waveshape, while others employ more complex load models—both of which increase the complexity of delay calculation significantly. These types of characterizations are mainly used for back-end verification processes for which speed is not critically important.
The delay and output transition time can also be characterized via look-up tables. The construction of such a table is illustrated in FIG. 2. Generally, gate delays may be characterized with look-up tables, they may be equally applicable to k-factor delay models (regression fit of table data) as well.
Due to the increase in total metal resistance with scaling, and the tendency for the effective gate output resistances to decrease as technologies are advanced, the RC shielding effect becomes significant for deep submicron CMOS. To illustrate this point, consider a simple gate model driving a distributed RC interconnect, with a load capacitance at the end of the line, as shown in FIG. 3. Assume that a resistance and a Thevenin voltage source that are functions of input transition time and output capacitance load model the gate. In this case, assume that the gate output resistance, Rd, and Thevenin voltage signal were selected as those values that would yield the same output delay and transition time as the actual gate when the load is the total capacitance, CM+CL.
If Rd>>RM, then the gate delay is accurately characterized by the empirical model as a function of total capacitance. However, if one considers the same gate resistance and total load capacitance, but increases the metal resistance so that Rd<<RM, the gate delay at node vout will decrease. This decrease in delay is due to the metal resistance shielding a portion of the downstream load capacitance. The difference in responses is sketched in FIG. 3. Note that the gate delay decreases, but the overall delay at CL would increase due to an increase in RM. In addition, the responses for lines with significant metal resistance also tend to have non-digital shaped waveforms as shown.
In order to preserve the simplicity and efficiency of the empirical gate models for complex RC loads, one can map the complex load to an effective capacitance (Ceff). Since its invention, the Ceff approach has been successfully used in the design of high-speed ICs.
The simplest model of a gate and corresponding interconnect delay would be a two-step approximation, in which a complete stage delay is the sum of the gate and interconnect delays. To capture the gate delay using a simple empirical gate delay model, the RC load is replaced by the effective capacitance, Ceff, and then the gate delay and output transition time is obtained from the empirical model of the gate. Once the transition time at the gate output is calculated, the gate output wave-form is approximated with a saturated ramp. The interconnect delay is then calculated using this saturated ramp waveform as the input excitation. This two-step delay approximation works well when the load seen by the gate is accurately approximated by the total capacitance of the net. That is, if the metal resistance is negligible, the whole interconnect behaves like an equi-potential surface and the waveform at the gate output appears instantly at all fan-outs—i.e., there is no slope degradation or delay from gate output to fan-outs.
However, with increasing effects of interconnect resistance, gate output waveforms become increasingly non-digital and can no longer be modeled as saturated ramps. A conventional response to this problem is to use Thevenin gate models based on the Ceff concept. As shown in FIG. 4, a time-varying voltage source and a constant resistor replaces the gate. Based on a gate input wave-form, A, the gate is modeled as a linear Thevenin equivalent with a time-varying voltage waveform, T. The voltage waveshape T is iteratively determined as a function of the effective capacitance. Once the Thevenin model is parameterized, the interconnect is then attached to the linear gate model and a linear circuit evaluation is performed. With this modeling approach, the RC nature of the interconnect can be captured to obtain the gate output and fan-out waveforms more accurately.
The Thevenin voltage waveform T is generally modeled via a saturated ramp voltage that is characterized by a transition time Δt and a delay t0. The values of the Thevenin model parameters, t0, Δt, and Rd, are chosen such that the waveshape at the model output and the actual waveform from the library lookup match. However, since the look-up tables and k-factor equations are not defined for noncapacitive loads we need to use an intermediate effective capacitance value, Ceff. To find Ceff, a commonly used procedure is to compute a capacitance value such that when the driver is the Thevenin model, the average current into the interconnect and Ceff are equal. Once Ceff is computed, it is used in the library lookup to obtain the gate output (delay and transition time). Then a Thevenin voltage is computed to match the library response.
A problem with conventional approaches, including the Thevenin equivalent model, is that they fail to represent the real physics or transistors, and hence, the calculations provide less than desired accuracy in gate modeling. In addition, in models such as Thevenin equivalents, only resistance is accounted for while in actuality, there is also capacitance present at the gate that does not get accounted. Again, this leads to less than desired accuracy in gate modeling. Yet another problem is that the actual circuit resistance is nonlinear although conventional modeling show resistance as linear, which also leads to further inaccuracies in gate modeling.
Therefore, there is a need for a system and process to provide more accurate gate modeling for use in circuit models and designs.

Modeling interconnected propagation delay for an integrated circuit design


A rotating shaft (23) is inserted through an axial center of a cutter wheel tip for scribing a brittle object. The rotating shaft (23) is integrally provided with the cutter wheel tip. The rotating shaft (23) is inserted into supporting holes (14) provided in side walls (11) of a tip holder (11) so as to be supported. A groove (13) is formed in an upper portion of each supporting hole (14) along an axial direction of the supporting hole (14).

A glass plate used for a liquid crystal display panel or the like is usually produced by first scribing a large mother glass plate with a wheel cutter so as to form scribe lines, and then cutting the mother glass plate along the scribe lines into pieces of a prescribed size. The wheel cutter includes a circular cutter wheel tip held by a tip holder.
The cutter wheel tip is circular, has an outer circumferential surface, and is formed of a hard metal, sintered diamond or the like. A center of the entire outer circumferential surface projects in such a manner so as to be sharp and acts as a blade edge.
The cutter wheel tip has a hole at an axial center thereof, and a rotating shaft is passed through the hole. The hole has a diameter which is slightly larger than the diameter of the rotating shaft, such that the cutter wheel tip is freely rotatable with respect to the rotating shaft.
Each of two side portions of the rotating shaft are respectively supported by a pair of walls included in the tip holder. The cutter wheel tip is located between the walls. The two side portions of the rotating shaft are inserted into supporting holes of the walls.
FIG. 16 is a cross-sectional view of such a rotating shaft 33 which is supported by the walls. As shown in FIG. 16, each of two side portions (only one is shown) of the rotating shaft 33 is inserted into a supporting hole 34 formed in a wall 31 to be supported. The inner diameter of the supporting hole 34 is slightly larger than the outer diameter of the rotating shaft 33, so that there is a slight tolerance G between an inner circumferential surface of the supporting hole 34 and an outer circumferential surface of the rotating shaft 33.
For scribing a brittle object such as a glass plate or the like, the wheel cutter is moved with respect to the brittle object in a prescribed scribing direction. The cutter wheel tip runs on a surface of the brittle object so as to be pressed thereon. In this state, the wheel cutter keeps on moving on the surface in the prescribed scribing direction.
When the cutter wheel tip runs on the brittle object, a force is applied on the cutter wheel tip and also on the rotating shaft 33 engaged with the cutter wheel tip. When the cutter wheel tip is pressed on the brittle object, the rotating shaft 33 is elevated and pressed on an upper portion of the inner circumferential surface of the supporting hole 34.
The rotating shaft 33 contacts the upper portion of the inner circumferential surface of the supporting hole 34 at one contact line Y. In this state, the entire reaction force from the inner circumferential surface of the supporting hole 34 is applied on the rotating shaft 33 at contact line Y. When impact is applied on the cutter wheel tip, the impact is also applied on the rotating shaft 33 engaged with the cutter wheel tip. Then, a reaction force from the entire inner circumferential surface of the supporting hole 34 is applied on the rotating shaft 33 at contact line Y . As a result, the rotating shaft 33 can be undesirably broken at contact line Y.
When the cutter wheel tip pressed on the surface of the brittle object moves on the surface, a frictional force is applied on the rotating shaft 33 due to a reaction force applied on the rotating shaft 33 from the inner circumferential surface of the supporting hole 34, thus restricting the rotation of the rotating shaft 33. The cutter wheel tip rotates with respect to the rotating shaft 33, and thus the edge of the cutter wheel tip, rotatably engaged with the rotating shaft 34, moves while rotating in contact with the surface of the brittle object. Thus, the surface of the brittle object is scribed.
The conventional cutter wheel having the above-described structure has the following problems. The rotating shaft 33 has substantially the same outer diameter as the inner diameter of the supporting hole 34. Therefore, it is possible that the reaction force applied on the rotating shaft 33 from the inner circumferential surface of the supporting hole 34 is too low to stop the rotation of the rotating shaft 33 with certainty, resulting in the rotating shaft 33 slipping and thus further rotating undesirably. Especially when the pressure contact force between the supporting hole 34 and the rotating shaft 33 changes due to a change in the pressing force of the cutter wheel tip on the surface of the brittle object which occurs during the scribing operation, or due to a change in the scribing speed of the cutter wheel tip, the possibility of the rotating shaft 33 slipping so as to rotate on the brittle object surface increases.
When the rotating shaft 33 slips and rotates, the resistance caused by friction between an outer circumferential surface of the rotating shaft 33 and an inner circumferential surface of the cutter wheel tip having a slightly larger diameter than the diameter of the rotating shaft 33 becomes unstable. This may undesirably result in the quality of the scribe lines being non-uniform.
Since the rotating shaft 33 slips, the outer circumferential surface of the rotating shaft 33 and the inner circumferential surface of the supporting hole 34 are abraded, which may undesirably prevent long and stable use of the wheel cutter.
When the rotating shaft 33 slips, a force is applied on the rotating shaft 33 from the inner circumferential surface of the supporting hole 34 in an abnormal direction, which may undesirably damage the rotating shaft 33.
The present invention, for solving the above-described problems, has an objective of providing a tip holder for realizing long and stable use of a rotating shaft engaged with a cutter wheel tip.
Another objective of the present invention is to provide a tip holder for allowing the cutter wheel tip to stably scribe a surface of a brittle object.