A method of designing a layout for manufacturing an integrated circuit is provided, in which computationally intensive portions of the design process, such as simulation of an image transferred through a mask design, or simulation of electrical characteristics of a circuit, are performed more efficiently by only performing such computations on single instance of computational subunits that have an identical geometrical context. Thus, rather than performing such computations based on the functional layout, for which typical design process steps result in significant flattening of the functional hierarchy, and therefore increase the cost of computation, the invention performs simulations on computational subunits stored in a hierarchy based on geometrical context, which minimizes the cost of simulation. The resulting simulation results are subsequently assembled according to the functional layout.

In the manufacture of integrated circuits, in particular, during the design of very-large-scale integrated (VLSI) circuits, the complexity of preparing and validating the effectiveness of circuit and mask layouts for many millions of devices on a single chip has resulted in simulation of those layouts as a critical component of design methodologies. However, the complexity and size of such simulations results in significant turnaround time.
For example, photolithography, or lithography, is typically used to transfer patterns relating to the layout of an integrated circuit onto a wafer substrate, including, but not limited to, materials such as silicon, silicon germainium (SiGe), silicon-on-insulator (SOI), or various combinations thereof. The drive to improve performance of VLSI circuits results in increasing requirements to decrease the size of features and increase the density of layouts. This in turn increasingly requires the use of resolution-enhancement techniques (RET) to extend the capabilities of optical lithographic processes. RET includes techniques such as the use of optical proximity correction (OPC), sub-resolution-assist-feature-enhanced lithography (SRAF) and phase-shifted-mask-enhanced lithography (PSM) or alternating phase-shift mask (altPSM) technology.
Among the several forms of Resolution Enhancement Techniques (RET), the iterative Model-Based Optical Proximity Correction (MBOPC) has established itself as a method of choice for compensation of the mask shapes for lithographic process effects. Conventional MBOPC tools work include the following steps in a manner similar to the following. An initial mask layout, typically based on the circuit design layout, is provided as input to the MBOPC tool. The shapes on the mask design (henceforth referred to as the mask) are typically defined as polygons. A pre-processing step is performed that discretizes (i.e. divides) the edges of each mask shape into smaller line segments. At the heart of the MBOPC tool is a simulator that simulates the image intensity at a particular points representing each of the line segments, which is typically at the center of each of the line segments. The OPC methodology, as embodied in an OPC tool, compares the simulated image to a desired target image to be printed on the wafer, and based on the deviation of the simulated image from the target image, the OPC tool causes the segments to be moved outward or inward from the feature interior, relative to their original position on the mask shape, to compensate for the deviation of the expected (simulated) image from the target image. This process is repeated iteratively, until, as a result of the modification of the mask shapes, the image intensity at these pre-selected points matches a threshold intensity level, within a tolerance limit.
While the quality of the OPC may improve as the number of segments increases, the efficiency of an MBOPC tool may decrease as the number of segments it simulates and iterates over in each iterative step increases. The number of segments in turn depends on the number of edges in each mask shape. In a typical mask there can be billions of shapes representing devices. Each shape can be divided into hundreds of segments. If all the segments are corrected independently, it may take some where between 150,000-250,000 CPU Hours to apply RET and OPC on a mask and use verification to detect its printability. Since both hardware and software cost depends on the total usage of CPU hours, in real dollar term this can be a significant expense.
In the current art this is made more efficient by taking advantage of the original or the designer imposed hierarchy which is also known as the native hierarchy of the design, which is a hierarchical representation of a layout based on functional reuse. In traditional representations of layouts there are a lot of circuits (such as a basic latch, de-capacitors) and combination of circuits (such as memory cells) that are used and reused again and again. This representation is known as the Hierarchic Tree in the design community, for example, circuit layout 110 in FIG. 1A. Though this is referred to as a tree, it is actually stored as Directed Acyclic Graph (DAG). Referring to FIG. 2, an example of a circuit layout 110 stored as a DAG is illustrated. C1 is a prime cell, which represents the entire layout of shapes for a given level of a circuit layout. C2 and C3 represent children of the prime cell C1. Stated another way, in this example, C1 consists of many repetitions of identical instances of two different cells C2 and C3, wherein an identical instance may include a rotation of the cell. Similarly, C2 consists of multiple repetitions or instances of child cells C4 and C5. C3 consists of multiple repetitions of children cells C6 and C7, and C4 consists of multiple instances of C8 and C9 and C5 and C6 consists of multiple instances of C10. In this example of a DAG 20, cells C7, C8, C9, and C10 are leaf nodes, which are nodes that do not have children of their own. Leaf nodes, such as cells C7, C8, C9 and C10, typically represent basic polygon shapes used as building blocks for devices, but typically do not themselves have functional significance. In typical circuit layouts, non-leaf nodes represent the combination of transistors or other devices, and combinations thereof, whose functions are repeated throughout the circuit layout. Each non-leaf node is known as a Cell. The root node C1 of the DAG is known as the Prime Cell, which represents the entire layout of a layer.
There are mainly two reasons why functional hierarchy is important for a circuit layout design. First, it helps the designers to reuse their design over and over again. Second it helps to make a design very compact. The use of a functional hierarchical design can save both memory and computation time, since computations, such as circuit or lithographic process simulations, need to be performed only once for each hierarchically stored cell and the computational results for a hierarchical cell may be applied to every instance of the cell that is repeated within the layout.
During the design process, some operations may cause the original hierarchy to be lost, which is referred to as a flattening of the hierarchy. For example, FIG. 3 illustrates a hierarchy tree 30 for a root node A (i.e. the prime cell in a DAG), including non-leaf nodes B, C, D, E, and multiple occurrences of leaf nodes "shape 1", "shape 2", "shape 3" and "shape 4" associated with certain non-leaf nodes A through E. Since each non-leaf cell B-E represents a repeated function within the root cell A, the characteristics of root cell A may be represented by computing the characteristics of a single occurrence of each non-leaf cell B-E, and assembling these characteristics according the hierarchy in order to obtain a representation of the root cell A.
However, an operation on the design that removes the repeated functional characteristics of the non-leaf nodes B, C, D and E within root node A, will result in a flattened hierarchy tree 31 at the root node A, such that the non-leaf nodes for the tree rooted at that node A are removed, and stores all occurrences of the leaf node shapes of the leaf nodes in the flattened root node A′. In this example, the flattened hierarchy 31 now contains N occurrences of shape1, M occurrences of shape2, L occurrences of shape3 and K occurrences of shape4, where N, M, L and K are typically in the order of millions of occurrences.
Flattening increases computational and storage requirements because simulation of the characteristics of an individual non-leaf cell B-E can no longer be applied to represent the characteristics of the flattened root cell A′. Rather, all occurrences of the leaf cells, or shapes "shape1", "shape2", "shape3" and "shape4" must be provided within the layout of the flattened cell A′, and computations, such as a simulation, must be performed on the entire flattened cell A′ containing all occurrences of the leaf cells.
Flattening of the original or the native hierarchy may occur in both Rule-based and Model-based lithographic computation. In case of MBOPC, shapes in the region or vicinity of optical influence around the point of interest are used for computing the image intensity at the point of interest. The effective region of optical influence (ROI) is the region enclosed by a boundary that is at a distance beyond which a feature outside of that boundary in the layout does not have a substantial effect on the optical process of imaging a particular feature at the point of interest. Stated another way, features outside of the ROI boundary will have substantially insignificant effects, for practical purposes, on the optical process of imaging the particular feature around which the ROI is formed. For example, in a lithographic process with wavelength of light of 193 nm and NA=0.85, and the optical aperture of 0.75, the ROI can be 0.8-3 microns in length. The half of the ROI dimension is often referred to as the Optical Radius. In this example the Optical Radius varies from 0.4 micron to 1.5.
Now consider a shape at the boundary of a cell in the hierarchy tree. Its vicinity region may overlap two adjacent cells within the assembled or flattened layout. After OPC, a new shape may have been created, which is unique and can not be repeated anywhere in the hierarchy tree. This would mean that any further computation done on this shape may not be re-used. This contributes to a loss of hierarchy. If this happens for a number of shapes, the hierarchy may be flattened significantly.
We can also lose hierarchy in case of rules-based computations. For example, in case of the placement of both SRAF and altPSM, one needs to consider the space between two shapes. New mask shapes such as an SRAF or the phase shapes in altPSM are placed within the space between design shapes to be printed, depending on the configurations of these shapes. If the space being considered is between two design shapes to be printed are each from two different but adjacent cells, the newly created mask shapes may be unique again and may contribute to a loss of hierarchy within the mask layout.
The effect is further exacerbated by the application of strong RET methods that may comprise several RET methods applied in tandem. For example, in altPSM masks, phase regions and SRAFs may be applied in the trim mask, and the modified trim mask containing the SRAFs and phase shapes may then be further modified by MBOPC. In each stage of the application of a separate RET, the hierarchy may flatten further and the final design may not exhibit any hierarchy at all.
The conventional method of handling hierarchy in a mask design process, comprising data preparation (data prep) which may include OPC and verification, is shown in FIG. 1A. Flattening of the hierarchy may occur as a result of many of the operations performed on the mask design during data prep.
In Block 101, the hierarchy manager 100 starts with an input layout 110 having a defined functional or native hierarchy of cells. Optionally, RET (Block 101A) may be applied prior to data prep. The hierarchy manager 100 typically deals with one cell in the functional hierarchy at a time (102).
If a cell is smaller than a pre-specified size, it is merged with a neighboring cell (103). A neighboring cell is a cell that shares a geometric boundary with another cell. For example, referring to FIG. 1B, small cell 109 that is adjacent to a small neighboring cell 111 is merged to create a single cell 112 in Block 103. Note that the neighboring cells may not be residing within the same parent in the hierarchy tree. Therefore, after merging, the merged cell 112 needs to reside in a common ancestor within the hierarchy. Therefore merging two neighboring cells would typically require exploding or flattening up to the lowest common ancestor in Block 104.
Referring to FIG. 1C, a portion of the hierarchy tree 113 is illustrated, in which child cells C14 and C15 have a common ancestor cell C12, and child cells C16 and C17 have common ancestor cell C13. Cells C12 and C13 in turn have common ancestor cell C11. Here, two small neighboring cells C15 (109) and C16 (111) are merged (Block 103 in FIG. 1A) to form merged cell C18 (112). However, the neighboring cells C15 (109) and C16 (111) do not have a common ancestor. Therefore, the hierarchy is flattened to the lowest common ancestor cell. In this case, cell C11 is the lowest common ancestor for cells C14, C17 and merged cell C18 (112). Thus the non-leaf nodes C12 and C13 are removed from the hierarchy to form a new flattened hierarchy 114 in FIG. 1C comprising the common ancestor cell C11 having child cells C14, C17 and merged cell C18 (112).
If a cell is too large, it needs to be broken into several smaller cells. For example, cell 115 is larger than a predetermined size, and is split into smaller cells 116 (Block 105). This operation may increase the number of child cells at a given level of the hierarchy, but may not significantly impact the cost of computation.
Next, each cell in the hierarchy may be a candidate for a model-based operation, such as MBOPC or manufacturability rule verification, that requires a simulation of the image. Such a cell is typically associated with a band of ROI (106) prior to performing the simulation. For example, referring to FIG. 1D, cell 117 when placed within the flattened layout, has neighboring cells 117A, 117B and 117C. To simulate the image associated with an instance of a cell 117 when placed within the layout, an ROI 217 is formed around cell 117 based on its placement within the flattened layout, in which cell 117 has neighboring cells 117A, 117B and 117C. Similarly, each of the neighboring cells 117A, 117B and 117C would have an associated ROI 217A, 217B and 217C, respectively, as illustrated in FIG. 1E.
Referring to FIG. 1F, the resulting enlarged simulation cell 118 contains the original cell 117 and the ROI 217. Although the original cell 117 may be stored hierarchically, some instances of cell 117 may have an ROI 217 that includes shapes from different neighboring cells than other instances of cell 117 within the layout. For example, the cell 117B is another identical instance of cell 117, and thus may be stored as a single instance of cell 117, the ROI 217B associated with cell 117B contains different shapes from neighboring cells when placed in the geometric context of the flattened layout. Thus some instances of cell 117 with its associated ROI 217, i.e. the enlarged simulation cell 118, would have a different optical context or region of optical influence than other instances of the enlarged simulation cell 118. Therefore, the larger simulation cells 118 and resulting images associated with cell 117 may no longer be able to be stored according to the original hierarchy for cell 117, and it may be necessary to explode or flatten the lowest common ancestor cell to accommodate the simulation cells that have different optical context regions, i.e. different ROI's.
Once the simulation cells and hierarchy are fixed in this manner, the shapes in the simulation cells are typically discretized or fragmented for simulation (Block 107). RET may be optionally be applied to the simulation cell, and RET shapes may be fragmented as necessary (Block 107). Since the application of RET may further alter the context region or ROI of each cell, further flattening of the layout may occur.
After application of OPC/RET, verification of manufacturability is performed on the OPC/RET processed cells (Block 108), which also includes simulation of the OPC/RET processed cells. Thus, any flattening of the hierarchy will result in longer turnaround times for the verification process. The results of OPC and RET is then output along with the verification results (Block 109). As discussed, current model-based design processes result in the flattening of the native or functional hierarchy several times. This flattening of the functional hierarchy decreases the efficiency of the computations and increases the memory requirements to store the data. As integrated circuits continue to evolve towards increased density and complexity, the design process will accordingly become more costly and difficult to perform efficiently.
Accordingly, it would be desirable to provide a method for improving the turnaround time for computationally intensive operations in the design process or tool for designing integrated circuits, such as lithographic mask design (e.g. MBOPC), mask manufacturability verification, or circuit design, while not reducing the quality or effectiveness of a computationally intensive design tool.

Methodology to improve turnaround for integrated circuit design using geometrical hierarchy


An example switched mode power supply includes a timer, a threshold adjust circuitry, a comparator, and a control circuitry. The timer times a duration between crossings of a phase-dimmed signal across a first threshold. The threshold adjust circuitry adjusts a second threshold representative of a desired output of the switched mode power supply, where the second threshold is adjusted responsive to the timed duration between crossings. The comparator compares a feedback signal with the second threshold and generates a comparison result. The control circuitry controls switching of a power switch responsive to the comparison result to regulate the output of the switched mode power supply.

1. Field of the Invention
The present invention relates generally to power supplies, and more specifically to power supplies utilized with dimmer circuits.
2. Discussion of the Related Art
Electronic devices use power to operate. Switched mode power supplies are commonly used due to their high efficiency, small size and low weight to power many of today's electronics. Conventional wall sockets provide a high voltage alternating current. In a switching power supply a high voltage alternating current (ac) input is converted to provide a well regulated direct current (dc) output through an energy transfer element. The switched mode power supply control circuit usually provides output regulation by sensing one or more inputs representative of one or more output quantities and controlling the output in a closed loop. In operation, a switch is utilized to provide the desired output by varying the duty cycle (typically the ratio of the on time of the switch to the total switching period), varying the switching frequency or varying the number of pulses per unit time of the switch in a switched mode power supply.
In one type of dimming for lighting applications, a triac dimmer circuit typically removes a portion of the ac input voltage to limit the amount of voltage and current supplied to an incandescent lamp. This is known as phase dimming because it is often convenient to designate the position of the missing voltage in terms of a fraction of the period of the ac input voltage measured in degrees. In general, the ac input voltage is a sinusoidal waveform and the period of the ac input voltage is referred to as a full line cycle. As such, half the period of the ac input voltage is referred to as a half line cycle. An entire period has 360 degrees, and a half line cycle has 180 degrees. Typically, the phase angle is a measure of how many degrees (from a reference of zero degrees) of each half line cycle the dimmer circuit removes. As such, removal of half the ac input voltage in a half line cycle by the triac dimmer circuit corresponds to a phase angle of 90 degrees. In another example, removal of a quarter of the ac input voltage in a half line cycle may correspond to a phase angle of 45 degrees.
Although phase angle dimming works well with incandescent lamps that receive the altered ac input voltage directly, it typically creates problems for light emitting diode (LED) lamps. LED lamps require a regulated power supply to provide regulated current and voltage from the ac power line. Conventional regulated power supply controllers typically don't respond desirably to a removal of a portion of the ac input voltage by a triac dimmer circuit. Regulated power supplies are typically designed to ignore distortions of the ac input voltage. Their purpose is to deliver a constant regulated output until a low input voltage causes them to shut off completely. As such, conventional regulated power supplies would not dim the LED lamp. Unless a power supply for an LED lamp is specially designed to recognize and respond to the voltage from a triac dimmer circuit in a desirable way, a triac dimmer is likely to produce unacceptable results such as flickering of the LED lamp, flashing of the LED lamp at high phase angles, and color shifting of the LED lamp. Thus, a power supply may include an improved conventional power supply controller that is designed to respond to a triac dimmer circuit by directly sensing the average value of the dimmer circuit output (in other words, the average value of the ac input voltage after the triac dimmer circuit has removed a portion of the ac input voltage) to determine the amount of dimming requested. In general, a smaller average value of the dimmer circuit output would correspond to a removal of a greater portion of the ac input voltage and thus a larger phase angle. As such, the improved conventional power supply controller utilizes this relationship to indirectly determine the phase angle and alter the quantity to which the output of the power supply is regulated. However, by indirectly measuring the phase angle in this manner, the amount of dimming detected (and hence the quantity to which the output of the power supply is regulated) is subject to variances of the ac input voltage. In other words, the accuracy of the phase angle measured through the average value of the dimmer circuit output is dependent on variances of the ac input voltage.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.

Phase angle measurement of a dimming circuit for a switching power supply


Pre-coated analysis substrates, and methods of making the substrates and using them to analyze animal tissue, are described. The pre-coated analysis substrates can be made by forming a matrix surface on an analysis substrate; adding a protease to the matrix surface to form a pre-coated analysis substrate; and placing an animal tissue specimen on the matrix surface. The animal tissue can then be analyzed by allowing the protease to partially digest the animal tissue specimen; and analyzing the partially digested animal tissue specimen by mass spectrometry.

The preparation of tissue samples is of primary importance to the nature and quality of information obtained using Imaging Mass Spectrometry (IMS). Unlike other analytical applications of mass spectrometry, where sensitivity and molecular specificity are the primary considerations for developing and validating methodologies, imaging applications require additional attention to preserve the spatial information in the sample. Furthermore, to promote adoption of the technology for significant translational applications targeting human health and disease, the ease-of-use of sample preparation methods must be optimized to ensure robust application of the technology by scientists and technicians whose primary training is in disciplines other than analytical chemistry.
Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) is a powerful technology in biological research enabling imaging of biomolecules within thin tissue specimens. In a typical experiment, a thin tissue (3-12 μm) is cryosectioned and placed on a conductive substrate. The tissue section is washed to remove salts and unwanted species, and then coated with a MALDI matrix that is typically a small organic molecule. The matrix aids in the desorption and ionization of the analytes. Analysis is performed by scanning a laser across the tissue section, acquiring mass spectral data at each defined x, y position. Two-dimensional maps of molecular distributions are generated from the spectral intensity for ions of interest across the sample.
In a typical MALDI imaging experiment, signals from proteins up to 25 kDa in molecular weight can be obtained directly from a tissue sample. Larger proteins are difficult to detect as the detection efficiency of a microchannel plate detector declines as the mass of the ion increases. Gilmore et al., Int. J. Mass Spectrom. 202, 217-229 (2000). Additionally, larger proteins are difficult to solubilize and incorporate into the matrix crystals. Franck et al., Med. Sci. Monitor 16 (2010), 293-299. This limitation precludes the observation of higher molecular weight biological species such as cytokines, growth factors, enzymes, receptors, and other biomolecules. Specific sample preparation methods have been developed to detect proteins up to 70 kDa in mass. These include the application of ferulic acid as a matrix and use of Triton X-100 and xylene to solubilize large proteins. Mainini et al., Mol Biosyst. 9 1101-1107 (2013); Leinweber et al., J. Am. Soc. Mass Spectr. 20, 89-96 (2009). Due to inherent limitations in detection and ion optics, such large proteins are difficult to detect on a routine basis. Chen et al., Anal. Chem. 75, 5944-5952 (2003).
An approach for measuring the distribution of large proteins (>25 kDa) in a tissue sample by MALDI-IMS involves their in situ tryptic digestion and subsequent MS imaging of generated fragments has been described. Groseclose et al., J. Mass Spectrom. 42, 254-262 (2007). In this approach, trypsin is serially spotted onto a tissue section to digest the proteins. Robotic spotters are used to control the digestion conditions, and in a second step, spot matrix on top of these individual regions. These post-coating methods have been used for the analysis of both formalin-fixed and fresh-frozen tissues. Groseclose et al., Proteomics 8, 3715-3724 (2008); Casadonte, R., and Caprioli, R. M., Nat. Protoc. 6, 1695-1709 (2011); Groseclose et al., J. Mass Spectrom. 42, 254-262 (2007). The advantages of this in situ digestion process include an on-tissue identification of proteins and a preservation of their spatial localization in contrast to LC-MS/MS approaches that are done on tissue homogenates where spatial information is limited. Further, the on-tissue analysis provides spatial distributions for the parent proteins and their daughter peptides that can be co-related and provide further verification in the identification. Despite these advantages, its use is challenged by a cumbersome process whereby sequentially spotting of matrix and trypsin onto a tissue sample can take hours for each tissue specimen. In addition, the robotic spotters needed for trypsin deposition are costly, and their spatial resolution is limited to 200-300 μm.
Previous work by the inventors has shown that matrix pre-coated targets can provide simple, standardized, and rapid methods for sample preparation. One group used pre-coated targets consisted of thin matrix films for the imaging of small molecules across a series of tissue sections. Grove et al., J. Am. Soc. Mass Spectr. 22, 192-195 (2011). Another group successfully demonstrated lipid imaging and protein distributions in brain and kidney tissues using such pre-coated slides. Yang, J. H. and Caprioli, R. M., Anal. Chem. 85 2907-2912 (2013); Yang, J. H. and Caprioli, R. M., J. Mass Spectrom. 49, 417-422 (2014). However, the need remains for improved methods of conducting Imaging Mass Spectrometry.

Pre-coated surfaces for imaging biomolecules


Disclosed are a current zero-cross detection device, zero-cross current signal acquisition circuit and totem pole bridgeless circuit system. The current zero-cross detection device includes a current transformer, first sampling switch, second sampling switch, sampling resister, comparator. The current transformer includes a primary winding and a secondary winding; the primary winding is connected to a circuit to be detected; two ends of the secondary winding are connected respectively to drain electrodes of the first and second sampling switches; source electrodes of first and second sampling switches are connected to ground; two ends of the sampling resistor are connected respectively to the drain electrode and source electrode of the second sampling switch; the negative input end of the comparator is connected to the drain electrode of the second sampling switch, its positive input end is connected to a reference voltage; the first and second sampling switches are in ON or OFF state.

Research on single-phase Power Factor Correction (PFC) technology is towards the trend of high efficiency and high power density, and the totem pole bridgeless PFC topology is proposed in responsive to this trend, as shown in FIG. 1. In the totem pole bridgeless boost converter circuit system, a first bridge arm unit, a second bridge arm unit, and a capacitor Co are connected in parallel, with one connected end connected to the ground; the first bridge arm unit has two working frequency switches S1 and S2 connected in series in the same direction; a second bridge arm unit has two switches S3 and S4 connected in series in the same direction; an AC power supply Vin and an inductor L are connected between the connection point of two diodes and the connection point of two switches.
In the abovementioned totem pole bridgeless PFC circuit system, due to constraints of the topology itself, the totem pole PFC cannot use the fast recovery diode characteristics to improve EMI (Electro Magnetic Interference) as the two-way switch bridgeless PFC does, meanwhile the hard switching characteristics of the CCM (Continuous Conduction Mode) mode cannot meet the growing demand for high efficiency in the industry, therefore the totem pole bridgeless PFC control policy described in this application is based on the TCM (triangular current mode) mode, according to the simple topology of the totem pole, the high power density and high efficiency requirements can be met simultaneously if it is to control to achieve zero voltage switching (ZVS) or valley switching (VS) feature in full input voltage and full load range in the TCM mode.
However, during the process of practicing and studying the abovementioned control policy, the applicants of the present application found that: in the relevant totem pole conversion circuit system, based on the above control idea, it needs to timely and accurately detect the inductor current zero-cross signal of the PFC to achieve the timing control of working frequency switches S1 and S2 and high frequency switches S3 and S4, so as to achieve the ZVS or VS control in the full input voltage and full load range in the TCM mode.

Current zero-cross detection device, signal acquisition circuit, and circuit system


A contact lens of generally disc-like configuration having a central axis extending through the contact lens and about which the contact lens is substantially symmetric in configuration. The contact lens has. a pupil zone through which the central axis extends and which comprises the area immediately circumferentially surrounding the central axis; PA1 an iris zone, which comprises the area circumferentially surrounding the pupil zone; and PA1 a peripheral zone which comprises the area circumferentially surrounding the iris zone and extends to the edge of the contact lens.. Further in the area immediately adjacent to the periphery of the iris zone and the contact lens and circumferentially extending therearound a band of dark substantially light-absorbing color is provided.

This invention relates to a contact lens, and, in particular, a contact lens which is provided with a dark masking ring.
The border area/zone between the iris and the sclera of the human eye is known as the limbal zone, and this zone is very deep in colour. In fact the colour is generally so deep as to be regarded as black.
The human eye is one of those parts of the human body which permanently shows the effects of disease and ageing, and one part thereof which readily shows this is the limbal zone. In a young healthy person the limbal zone is very deep and clear in colour, whereas the effects of illness, age and trauma can lead to a milking or clouding over of the limbal zone. This gives the person the appearance of age and relative ill-health.


Embodiments are described herein to identify matching users that share an affinity for particular subjects with a searching user. The embodiments may allow searching users to find and connect with matching users based on parameters, such as physical and/or virtual proximity of the users, one or more shared affinity subjects and/or privacy preferences associated with the users. The embodiments may provide notifications throughout the matching and connecting process and may allow connected users to manually and/or automatically share information with each other.

This specification relates generally to systems and methods for matching and connecting users based on proximity preferences and/or shared affinities to facilitate information exchange and other interactions among such users.
Individuals, groups, organizations and other entities often share a mutual affinity or interest in a particular area, topic or subject. For example, entities may share a mutual affinity for subjects such as music, geographic location, history, politics, educational subjects, interactions and others. In many cases, such entities may wish to communicate, interact, or otherwise establish relationships with one another.
Additionally, objects may be created or dynamically programmed such that they are related to one or more subjects (i.e., such that they have an "affinity" for such subjects) and, like entities, it may be beneficial for objects to connect with other similarly programmed objects. Such objects may include, for example, electro-mechanical and/or cybernetic machines and other computer systems; virtual reality or computer simulation "avatars"; reality constructs (e.g., robotics); extensible computer-program-code templates such as "classes" and the like; and/or Internet of Things ("IoT") devices.
Typically, in order for an entity and/or object (i.e., a "searching entity/object") to identify one or more other entities/objects that share a mutual affinity for a particular subject (i.e., "matching entities/objects"), the searching entity/object must conduct a search. For example, a searching entity/object that desires to find matching entities/objects may conduct a database search relating to a particular subject. Upon retrieving search results, the searching entity/object may then have to sort through the results in order to eventually communicate with one or more matching entities/objects.
Unfortunately, a simple database search will not return matching entities/objects that are not included in a searched database and/or that are not associated with a searched subject in the database. Moreover, even if a potential matching entity/object is included in the returned search, it may be difficult or impossible for the searching entity/object to establish a relationship with the matching entity/object. For example, the matching entity/object may not have their contact information listed or they may not be located within the same physical or virtual location as the searching entity/object.
Accordingly, there remains a need for improved systems and methods that identify and match entities/objects having a mutual affinity for one or more subjects. It would be beneficial if such systems and methods could be adapted to determine a physical and/or virtual location of such entities/objects in order to allow matches to be easily filtered by proximity. And it would be further beneficial if such systems and methods allowed entities/objects to set preferences relating to matching parameters and information that may be shared with other entities/objects, while providing notifications relating to determined matches and connections.

Affinity and proximity information exchange systems and methods


A debris barrier is installed and locked to the liner tieback extension. When it is time to check release from the liner before initiating a cement job the inner running string is lifted. The lock stays engaged to the liner tieback extension tube as the inner running string is lifted. In that manner the debris barrier remains in position during the lifting to determine release from the liner before cementing. After cementing, the inner running string is lifted further to eventually undermine the lock and capture the debris barrier to bring the debris barrier to the surface with the inner running string. The lock can be dogs or collets or the like. An inner sleeve or a lift sub with an upset can be the support whose axial movement beyond a predetermined value undermines the lock to release the debris barrier.

There are many occasions where an annular space between relatively moving tubulars can fill up with debris. In one case before cementing a liner that has been hung off an existing tubular through an inner running string, the inner running string is picked up far enough to determine that it is no longer secured to the liner so that after the cement job is done there are assurances that the inner running string will free to remove to the surface. Typically the inner running string is lifted a meter or more. During this lifting event debris that is in the vicinity can fall into the annular space between the liner and the running string. To combat this problem in the past debris barriers have been proposed which are basically annular shapes around the inner running string. Early efforts simply fixed the annular shape to the inner running string but this proved ineffective since on lifting the inner running string to make sure that there was release from the liner resulted in lifting the debris barrier too high and out of the liner tieback extension so that debris could still get into the annular gap between the running tools and the liner. Once debris gets into that gap there is a great chance that it may cause the inner running string to remain engaged to the liner via frictional forces or hydraulic locking the inner running string to the liner. If that happened a significant loss of time and cost in clearing the inner running string from the liner ensued and in some instances the inner running string could not be retrieved and sidetracking was then required.
From that point the focus shifted to ways to make the barrier effective downhole despite the significant amount of relative movement that takes place when confirming that the inner running string has released from the liner. In US Publication 2011/0108266 the debris barrier 7 is allowed to "float" on fluid introduced to an annular chamber below before the device is run in the hole. The problem with this design is that the debris can adhere the debris barrier to the lift mandrel that it surrounds with the unintended result of lifting the floating debris barrier away from its pool of fluid that was supposed to keep the barrier essentially stationary as the mandrel is lifted.
Other approaches touted the "hydraulic lock" where an elaborate system of seals to retain a volume of hydraulic fluid was used in an effort to keep the debris barrier in place. Such designs are illustrated in U.S. Pat. No. 6,408,945 (items 152 or 252) or U.S. Pat. No. 5,528,366 which is along the same line by the same inventor. The problems with this design are cost and reliability. The debris barrier had to have an internal reservoir that was initially filled at the surface and then used a network of seals to seal against the liner tieback extension so as to be able to maintain the liquid lock when the lift mandrel was lifted. Getting all these seals to effectively seal was key to the operation of the lock. However, there is the local debris issue and getting the seals to fit closely to the liner tieback extension that all could contribute to the loss of locking force. Finally the debris could wedge the barrier to the lift nipple to then put stress on the seals to hold the ever rising pressure if tandem movement occurred which could blow out a seal before surface personnel had any clue that such failure had occurred. In touting the hydraulic lock these references eschewed mechanical locking as undesirable and impractical in this application.
The present invention is a mechanical lock for the debris barrier. The barrier is locked when run in and remains locked as the lift nipple is raised. After a predetermined lifting the lock is defeated to allow the inner running string to be removed while capturing the debris barrier. Preferred designs of dogs and collets are disclosed. Those skilled in the art will gain a better understanding of these and other aspects of the invention from a review of the description of the preferred embodiment and associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.


In a gaming machine having virtual reels, certain symbols are modified to identify feature units associated with that particular symbol. The feature units carry over for multiple games until extinguished by being used. If a symbol having one or more feature units is involved in a winning combination, the function associated with its feature units, such as an award multiplier, is applied to the player's award. The symbols adjacent to a winning combination of symbols, or the symbols in the winning combination, may be augmented with a feature unit. A symbol accumulating a certain number of feature units may become a wild symbol. By continuing to accumulate feature units over many games, the symbols progressively become more valuable, and the player is incentivized to keep playing the machine. When the player cashes out, the feature units are extinguished.

Common video slot machines randomly select and display an array of symbols, using virtual reels, then grant an award to a player based on the occurrence of certain symbol combinations across paylines. Typically, the game ends after the symbols are displayed and the award, if any, is granted. No benefit is carried over from game to game, so the player does not become invested in playing that particular gaming machine.
U.S. Pat. No. 8,523,654 describes a game where game rules modify the function of a symbol for a particular game, such as making the symbol wild or causing it to enhance an award. However, such a modification is only for a single game then is extinguished. Therefore, the player does not become invested in the game and is not particularly incentivized to keep playing.
It is known to provide a "continuous" bonus game that carries over for multiple games until the bonus game is won. Therefore, the player has an incentive to keep playing the game since, the longer the player plays, the more likely the player will win the bonus game. However, the bonus game is typically a long term game which is only won infrequently and very slowly progresses with time. In other words, the incentive to keep playing is only marginally increased over time, and any reward for winning the bonus game only comes after a large number of games are played.
What is needed is new gaming feature that is added to a base game (rather than a bonus game), where the feature frequently enhances the award or winning percentage, and where aspects of the feature accumulate over a number of games to progressively increase the player's incentive to keep playing the gaming machine.

Gaming machine with carryover feature units associated with particular symbols


A propellant is ignited within a well to rapidly produce combustion gases to generate pressure exceeding the fracture extension pressure of the surrounding formation. Combustion gases are generated at a rate greater than can be absorbed into any single fracture, thereby causing propagation of multiple fractures into the surrounding formation. In one embodiment, each segment of the propellant is in the form of a solid cylindrical body of fuel/oxidizer surrounded by an expandable casing made of a material similar to a fire hose. A linear shaped charge extends between the casing and the propellant. Upon ignition of the shaped charge, combustion gases quickly stretch the casing thereby allowing the hot gases to surround and ignite the entire propellant surface area. The propellant then burns in a radially inward direction in a predictable manner. A computer program can be used to model the burn rate of the propellant to predict the resulting generation of combustion gases and fracture propagation, and thereby determine a suitable quantity and configuration of the propellant for creating multiple fractures in the surrounding formation.

1. Field of the Invention
The present invention relates generally to the field of fracturing wells. More specifically, the present invention discloses a method and apparatus for creating multiple fractures in wells using propellants.
2. Statement of the Problem
Hydraulic fracturing has been used in the oil industry for many years and has undergone evolutionary changes throughout this period. It has worked effectively in stimulating oil production from wells that were drilled vertically where the borehole passes through hydrocarbon formations having a thickness on the order of tens of feet that can be effectively tapped by a single pattern of fractures extending radially outward from the borehole.
The advent of horizontal well drilling techniques allows a borehole to travel within a hydrocarbon bearing formation for up to thousands of feet. The borehole typically travels through a series of natural fractures that are at some angle with respect to the borehole. When hydraulic fracturing is attempted in such a horizontal borehole, a single fracture pattern usually occurs located along the weakest natural fracture in the formation. This result occurs because hydraulic fluid used in the fracturing process is supplied from the surface and cannot be pumped down the well quickly enough to overload the single fracture that has occurred. If the single fracture is not overloaded, subsequent fractures will not occur since the pressure in the borehole will not rise to the fracture extension pressure of the stronger fractures.
The need to cost-effectively recover oil from tight sand formations presents another challenge. Vertical wells drilled in tight sands are not easily completed using conventional hydraulic fracturing techniques. A significant portion of the fracturing fluid tends to leak off along the well into surrounding formation, rather than serving to fracture the desired hydrocarbon-bearing formation.
A number of devices and processes have been invented in the past relating to fracturing wells, including the following:
______________________________________ Inventor U.S. Pat. No. Issue Date ______________________________________ Hill, et al. 4,633,951 Jan. 6, 1987 Hill, et al. 4,683,943. Aug. 4, 1987 Austin, et al. 4,974,675 Dec. 4, 1990 Jennings 4,711,302 Dec. 8, 1987 Wolcott 4,522,260 June 11, 1985 Wolcott 4,446,918 May 8, 1984 Ford, et al. 4,391,337 July 5, 1983 Hane, et al. 4,329,925 May 18, 1982 Godfrey, et al. 4,039,030 Aug. 2, 1977 Blauer, et al. 3,937,283 Feb. 10, 1976 Mohaupt 3,313,234 Apr. 11, 1967 Graham, et al. 3,170,517 Feb. 23, 1965 Marx 3,136,361 June 9, 1964 Riordan 3,101,115 Aug. 20, 1963 Bourne 3,064,733 Nov. 20, 1962 Hanes 3,002,559 Oct. 3, 1961 Scott 3,001,584 Sep. 26, 1961 Rachford 2,766,828 Oct. 16, 1956 ______________________________________
The closest prior art references are believed to be U.S. Pat. Nos. 4,633,951 and 4,683,943 of Hill, et al. These patents disclose a method and apparatus for fracturing in which the well casing is first filled with a fracturing fluid. A gas generating unit containing shaped charges for perforating the well casing, and a propellant is suspended in the fracturing liquid within the well casing. The fracturing fluid is pressurized from the surface to a predetermined threshold value. The gas generating unit then perforates the well casing and simultaneously ignites the propellant. The propellant forces the fracturing liquid through the perforations and fractures the surrounding formation.
The Rachford patent discloses a system for fracturing in which the well casing is first perforated. A body of propellant is suspended in the fracturing liquid within the well casing and then ignited. The propellant forces the fracturing liquid through the perforations and fractures the surrounding formation.
Mohaupt discloses another system for hydraulic fracturing in which the fracturing liquid is driven by a non-detonating propellant.
Ford, et al., discuss a fracturing apparatus using a high velocity jet to first perforate the well casing. A gas propellant charge carried by the apparatus is ignited to expand the perforation and fracture the surrounding formation. Column 1, lines 25-44 provides a brief synopsis of the prior art relating to propellant fracturing.
Austin, et al., discloses a method of fracturing horizontal wells. A perforating gun carrying explosive charges is used to perforate the well casing. Hydraulic fracturing is then applied.
The Wolcott patents use explosive charges to create rubblized zones connecting horizontal bore holes to increase permeability.
The Scott and Riordan patents discuss the use of propellant to generate a pulse-like pressure boost to supplement the available surface pump pressure in hydraulic fracturing. This is similar in a general sense to the method discussed in U.S. Pat. Nos. 4,633,951 and 4,683,943.
The Bourne patent is another method of hydraulic fracturing in which the well casing is first perforated with shaped explosive charges carried by a perforating gun.
Graham, et al. discloses a method of hydraulic fracturing in which the fracturing liquid is driven by high pressure gas pumped from the surface.
Godfrey, et al., disclose a system in which both a propellant and a high explosive charge are used for fracturing. The propellant is ignited first, followed by detonation of the high explosive. The propellant serves to maintain pressure caused by the high explosive over a longer period.
Hane, et al., disclose an apparatus for fracturing using multiple explosive charges. The remaining references are only of passing interest.
3. Solution to the Problem
None of the prior art references uncovered in the search disclose a method of fracturing using a propellant to rapidly generate a sufficiently large volume of combustion gases, without detonation, to overload the weakest fracture, and thereby create multiple fractures. In a horizontal well, the present method creates a series of plane fractures that are roughly parallel to each other along the length of the bore hole. In contrast, a vertical well will experience a fracture in the least principle stress plane, similar to those produced by conventional hydraulic fracturing, plus a second fracture in a plane perpendicular to the least principle stress plane. The rapid pressurization of the well bore resulting from the burning of the propellant causes the fractures to propagate at rapid extension velocities. These extension velocities are on the order of the sonic velocity of the propellant combustion gases.

Method of fracturing wells using propellants


A catalytic composite comprising a combination of catalytically effective amounts of a platinum component, optionally a second metal component such as tin or rhenium, and a halogen component with a porous carrier support material is disclosed. The platinum, second metal (if present) and halogen components are present in the catalytic composite in amounts, calculated on an elemental basis, of about 0.2 to about 0.4 wt. percent platinum metal, about 0.2 to about 0.5 wt. percent the second metal, and 0.5 to about 1.5 wt. percent halogen. Moreover, the metallic components are substantially uniformly distributed throughout the porous carrier support material. The support material is spherical gamma alumina having a characteristic pore structure including "superpores" (200-10,000 nm or greater) interconnected with "mesopores" (5-20 nm), wherein 80% or more of the pore volume (N.sub.2) resides in pores of less than 150 .ANG.. The principal use of the catalytic composite of the present invention is for hydrocarbon conversion, particularly in the reforming of a gasoline fraction.

Platinum catalysts and bimetallic catalytic composites of platinum and other metals, such as tin, on a refractory support are well known. See, e.g., U.S. Pat. No. 3,531,543 (Clippinger et al.), U.S. Pat. No. 3,745,112 (Rausch), U.S. Pat. No. 3,840,475 (Davis), U.S. Pat. No. 3,864,241 (Rausch), and U.S. Pat. No. 3,883,419 (Itoh et al.). The platinum, which is typically present in amounts of 0.1 to 5% by weight, is an active catalyst for hydrogenation or dehydrogenation and dehydrocyclization of vaporized hydrocarbons under appropriate process conditions; and deposited on suitable porous supports, platinum also is known to catalyze isomerization and cracking. Bimetallic catalysts, in which a second metal such as tin, cobalt, nickel, iron, copper, palladium, germanium, iridium, rhodium, rhenium etc. is used to stabilize or enhance the platinum activity, have been developed in order to prevent agglomeration of the platinum, facilitate regeneration and enhance selectivity, or, as in the case of rhenium, to reduce the amount of expensive platinum metal required to produce an active hydrocarbon conversion catalyst.
Bimetallic catalytic composites comprising a combination of catalytically effective amounts of platinum, a second metal (particularly tin) and a halogen component on a porous carrier material have been developed which exhibit good activity, selectivity and stability when utilized in hydrocarbon reforming processes
Reforming of hydrocarbon naphtha streams is a particularly important hydrocarbon refining process in which high octane hydrocarbon blending components for gasoline or for chemical processing feedstocks are obtained from low octane petroleum fractions. Catalytic reforming of naphthas has been performed with a wide range of platinum-containing catalysts in fixed and moving bed processes.
In the manufacture of reforming catalysts, many factors are considered with a view to optimizing the volume of high octane materials produced using a particular catalyst. For example, the amounts and types of metals combined with the platinum may be varied, as well as the chemical nature of the bimetallic combination, that is, whether the deposited metals are in a positive oxidation state, elemental, or form a solid solution (alloy). See, e.g., U.S. Pat. No. 4,016,068 (Rausch) and U.S. Pat. No. 3,759,823 (Davies et al.).
In addition to varying the amount of platinum or the types and content of any other metallic components, the physical properties of the catalyst support may also be varied with a view to altering the overall properties of the catalytic composite. See, e.g., U.S. Pat. No. 4,703,031 (Unmuth et al.).
Applicants have found that formation of an improved catalytic composite comprising a combination of elemental platinum, or elemental platinum and a second metal in elemental form selected from tin, cobalt, nickel, iron, copper, palladium, germanium, iridium, rhodium or rhenium, and a halogen component, uniformly deposited on a unique porous, high surface area, spherical alumina carrier such that the platinum and tin components are uniformly dispersed throughout the porous carrier support material, provides an improved reforming catalyst having activity, selectivity and stability characteristics so that the average yields of C.sub.5+ reformate over a cycle are increased and the operation of the catalyst at high severity conditions is improved over catalytic composites prepared according to the prior art. Catalytic composites prepared as described herein, therefore, represent an advance in the art by enabling more efficient naphtha reforming processes and producing higher quality gasolines and chemical processing feedstocks.

A process for reforming a gasoline fraction


A method and associated apparatus for disinfecting at least one banknote, each banknote including a substrate, visual data, and a security feature, including disposing the at least one banknote in an oxygen-free environment, and exposing the at least one banknote to a temperature and for a duration sufficient to disinfect the at least one banknote and not compromise the security feature and the visual data, where to disinfect the at least one banknote includes to significantly deactivate, kill, or eliminate one or more pathogens from the at least one banknote.

Since the outbreak of the COVID-19/SARS-CoV-2 virus and the ensuing global pandemic, there has been a great deal of activity related to methods of inactivating this virus and other viruses and pathogens on a variety of surfaces and personal protective equipment.
Important surfaces are found on banknotes, which are essentially two-surface structures and are commonly handled in the normal course of daily commercial transactions. Several methods have been proposed to handle pathogens on banknotes, including the use of supercritical CO2, as taught in U.S. Pat. No. 9,610,619, and the heating of banknotes for extended periods of time in air atmospheres, as described in U.S. Pat. Nos. 6,946,106 and 5,626,822. The patents that describe methods involving heat and transport mechanisms require lower temperatures to avoid damaging the paper or polymer substrates and the attendant security features of banknotes, particularly fluorescent pigments. Such security features are an expensive aspect of the banknotes.
Studies by various groups have shown that the COVID-19/SARS-CoV-2 virus can last up to 28 days at a temperature of 20° C. on both polymer banknotes and paper banknotes. FIG. 1 provides data from the Australian Centre for Disease Preparedness [Riddell et al. Virology Journal, 2020] concerning inactivation rate coefficients for various surfaces. Based on this data, at a temperature of 200° C., a paper banknote would be sterilized (Log10 drop of 6 orders of magnitude) in 2 hours. Previous inventions limit the temperatures to well under 100° C. to avoid damaging the banknotes. At the lower temperatures in these previous inventions, e.g., 40° C., a decrease of 6 orders of magnitude would require approximately three days for sterilization.

Heat treatment of banknotes in an oxygen-free environment


Cryptographic systems and methods are provided in which authentication operations, digital signature operations, and encryption operations may be performed. Authentication operations may be performed using authentication information. The authentication information may be constructed using a symmetric authentication key or a public/private pair of authentication keys. Users may digitally sign data using private signing keys. Corresponding public signing keys may be used to verify user signatures. Identity-based-encryption (IBE) arrangements may be used for encrypting messages using the identity of a recipient. IBE-encrypted messages may be decrypted using appropriate IBE private keys. A smart card, universal serial bus key, or other security device having a tamper-proof enclosure may use the authentication information to obtain secret key information. Information such as IBE private key information, private signature key information, and authentication information may be stored in the tamper-proof enclosure.

This invention relates to cryptography, and more particularly, to security devices for use in cryptographic systems and to methods for using such security devices.
A variety of cryptographic techniques are used to encrypt data and to create digital signatures. With symmetric key cryptographic systems, a pair of users who desire to exchange data securely use a shared symmetric key. With this type of approach, a sender of a message uses the same key to encrypt the message that a recipient of the message uses to decrypt the message. Symmetric key systems require that each sender and recipient exchange the shared key in a secure manner.
Public key systems may also be used to exchange messages securely. With public-key cryptographic systems, two types of keys are used—public keys and private keys. A sender of a message may encrypt the message using the public key of a recipient. The recipient may use a corresponding private key to decrypt the message.
One conventional public-key cryptographic system that is in use is the RSA cryptographic system. Each user in this system has a unique public key and a unique private key. A sender may obtain the public key of a given recipient from a key server over the Internet. To ensure the authenticity of the public key and thereby defeat possible man-in-the-middle attacks, the public key may be provided to the sender with a certificate signed by a trusted certificate authority. The certificate may be used to verify that the public key belongs to the intended recipient of the sender's message. Public key encryption systems such as the RSA system that use this type of approach are referred to as PKI (public-key infrastructure) cryptographic systems.
Identity-based-encryption (IBE or IB) public-key cryptographic systems have also been proposed. As with PKI cryptographic systems, a sender in an IBE cryptosystem may encrypt a message for a given recipient using the recipient's public key. The recipient may then decrypt the message using the recipient's corresponding private key. The recipient can obtain the private key from a private key generator associated with the recipient.
Unlike PKI schemes, IBE schemes generally do not require the sender to look up the recipient's public key. Rather, a sender in an IBE system may generate a given recipient's IBE public key based on known rules. For example, a message recipient's email address or other identity-based information may be used as the recipient's public key, so that a sender may create the IBE public key of a recipient by simply determining the recipient's email address.
Public key cryptographic systems may be used to produce digital signatures. A recipient of a message that has been digitally signed can use the digital signature to verify the identity of the message's sender and to confirm that the message has not been altered during transit.
In a typical digital signature arrangement, a sender uses a cryptographic hash function to produce a message digest. The message digest is much smaller than the original message, but is still unique to the message for practical purposes. The sender then uses the sender's private key to sign the message digest. The process of signing the message digest uses a mathematical operation that can only be performed by the sender who possesses the private key. The message and signed message digest (the "digital signature") may then be sent to a recipient.
The recipient of the digitally-signed message can apply the same hash function to the received message to produce a message digest. Using the public key of the sender, the recipient can attempt to verify the signed version of the message digest that the recipient has received from the sender. The verification procedure uses the sender's public key in a mathematical operation to determine whether the signature was indeed created from the same message digest using the correct private key. If the verification function is successful, the signed version of the message digest will be proven to originate from the message digest that the recipient has produced by applying the hash function directly to the message. A successful verification operation therefore allows the recipient to confirm the true authorship of the message and to confirm that the message has not been altered.
By using both public key signatures and public key encryption, messages can be sent securely and authorship and message authenticity can be verified.
PKI systems are available in which PKI private keys are stored on a portable security device such as a smart card. When a sender desires to encrypt or digitally sign a message, the sender can insert the smart card into a computer. A PKI private key from the security device can then be used to perform the desired cryptographic operation. Because smart cards are small and portable, a sender can easily transfer a smart card to different locations.
With conventional arrangements, it is not possible to use IBE information with smart cards. There are also difficulties associated with accurately and securely distributing private key information to portable devices such as smart cards.
It is therefore an object of the present invention to provide improved security device arrangements for PKI and IBE cryptosystems.

This patent is subject to a terminal disclaimer.

Security device for cryptographic communications


A ball valve includes a valve seat having a chamber therein and bores communicated with the chamber, a ball, which has a plurality of channels, received in the chamber, a shaft connected to the ball, and a plurality of lids connected to the valve seat to close the bores. The ball valve further includes two plugs received in the chamber, each of which has a through hole and a concave portion fitting the ball to completely cover the ball therein when the first plug is combined with the second plug, a first recess, two second recesses at opposite sides of the first recess and two slot around the second recesses respectively, wherein the slots form two receiving slots when the first plug is combined with the second plug, and two pads, each of which has a through hole, received in the receiving slots respectively to cover the ball.

1. Field of the Invention
The present invention relates generally to a ball valve, and more particular to a ball valve with a leakage-proof between the ball and the valve seat. The ball valve of the present invention is easy to assemble also.
2. Description of the Related Art
FIG. 7 shows a conventional multi-way ball valve, which includes a valve seat 100, a ball 200, a shaft 300 and four lids 400. The valve seat 100 has a chamber 101 therein and four bores communicated with the chamber 101. The ball 200, which is received in the chamber 101 of the valve seat 100, has two channels 201. The shaft 300 is inserted into the bore of the valve seat 100 and connected to the ball 200. The shaft 300 is turned to rotate the ball 200 to change the orientations of the channels 201. The lids 400 are fixed to the valve seat 100 to close the bores respectively, each of which has a pad 401 at an interior side thereof for leakage-proof.
The pads 401 of the lids 400 are pressed on valve seat 100 rather than the ball 200, such that there is a residual space 102 in the valve seat 100. Fluid flowing through the ball valve will flow into the residual space 102 when the ball 200 is turned. If the fluid is a putrescible fluid, the fluid received in the residual space 102 will be putrefied after a long time of use, and the putrefactive fluid may be mixed with the flesh fluid and flow out that will cause pollution of the fluid.
An improved ball valve provides the lids with a concave portion at the interior side to fit the ball. This kind of lid is provided with two inclined face at opposite sides of the concave portion that make the ball valve is hard to assemble. Furthermore, it breaks the leakage-proof also.


The present invention relates to a connection system for electrical cables which operate under vacuum and carry high-voltage electric pulses or currents.

The technical field of the present invention covers connection systems for high-voltage currents (several tens of kv).
In this field the industrial applications sometimes require cables carrying high-voltage currentsxe2x80x94which also may exhibit of high and variable densitiesxe2x80x94to cross what in general are metallic walls. A particular problem arises when a vacuumxe2x80x94or sealing relative to another gasxe2x80x94must be maintained on one side of the wall. The same difficulty is encountered when two cables of this kind must be connected in vacuum.
Several types of connection systems are presently available to solve the problem of high-voltage cable connection or wall feedthroughs. Such devices can be found in high-voltage coax(ial) connector catalogues published by specialized suppliers such as RADIALL, ALCATEL, ETAT, LEYBOLD, PFEIFFER, VARIAN or VEECO. Most of these devices consist of a set of a male and female connector elements (to connect one insulated coaxial line to another which is also insulated) or of a wall-mounted connector element and a plug (when joining an insulated coax line to a non-insulated line in air). One of the two connector elements, or the wall-mounted connector element, is then affixed to the wall being crossed and hermeticity is assured by conventional seals on the two sides of the wall.
However, because these connector elements entail electrical contact and a break in dielectric on each side of the wall, they will operate properly under high voltage only if the connection is implemented at atmospheric pressure. As soon as these connector elements are made to operate in vacuum, arcing arises at the surface along the dielectric junctions of the connection systems and the voltage drops.
Moreover the conventional plug-jack connections entail high inductance on account of the substantially different diameters of the inner and outer conductors, said high inductances hampering rapid pulse propagation for instance from a capacitor discharge through the connection. While operation remains feasible by increasing the power of the current generator when using DC, the problem becomes practically prohibitively difficult if a high current is desired by a very fast capacitor discharge.
Moreover the conventional connection systems permanently affix either the case of one of the connectors, or the wall-mounted element to the wall, thereby precluding rapid engagement and disengagement of the cable ends with and from the wall.
Therefore it is the objective of the present invention to create a connection system wherein the dielectrics remain immersed in a gas atmosphere or any other fluid even when part of the connection system is in a vacuum. The invention moreover implements its connection by retaining a coaxial geometry which is close to that of the cables and in this manner allows easily disengaging both cables from the wall to which they are mounted.
The connection systems of the invention are able to withstand voltages that per se do not restrict the application of this invention, even in a deep vacuum, because the configuration of the invention, by means of an increase in length of the connection system, allows adjusting its arcing strength merely by increasing the length of the dielectric on which the electric arc might travel. Significantly the increase in length does not entail increased radial bulk, and consequently the connection inductance is not increased.
For that purpose the invention proposes a connection system comprising a metal outer shell connected to the grounding braids of the cables to be joined, furthermore a dielectrically insulating sleeve inside said metal shell and enclosing the inner conductors of the two cables and their insulating sheaths, said connection system being fitted with a sealed cavity between the insulating sheaths of the cables being joined and the insulating, dielectric sleeve; said cavity is always exposed to a gas, preferably atmospheric air introduced in the cavity during assembly, or it remains filled with a hydraulic fluid even when the connection system or part of it is placed into an enclosure under vacuum. The gas pressure or the presence of the fluid shall be preserved in said cavity by using seals situated on one hand on the end of one of the two cables and on the other hand between the dielectrics of the particular cable sheath and the end of the insulating sleeve. Sealing the cable end must be implemented both on the inner cable conductor to preclude leaks through the cable inside and on the insulating sheath in order to attain the desired sealed cavity.
Where the cable must cross a wall separating a gas atmosphere from an enclosure at vacuum, sealing can be implemented only at one end of the dielectric sleeve; on the other hand, if the connection system is meant to be fully situated in a vacuum, sealing will be required at the ends of both cables and at the ends of the insulating sleeve.
Preferably the outer metal shell and the dielectric, insulating sleeve exhibit a cylindrical cross-section in order to enclose at minimal bulk the cable ends and hence entailing minimal inductance, further to assure good shielding against electromagnetic radiations. Moreover said shell and sleeve also may consist of two tubes, one being metallic, the other a dielectric, which nest in each and are affixed to each other. In particular this configuration offers the advantage of easily positioning the cables inside the metal shell and dielectric insulating sleeve and facilitate maintenance of the assembly.
Preferably the cable end may be sealed by a plug crimped on the cable and its insulating sheath. If necessary the plug shall be soldered on the inner conductor to seal off the inside of the cable inner conductor.
Preferably the cavity at the end of the sleeve is sealed by inserting an O-ring between the insulating sleeve""s dielectric and the dielectric of the insulating sheath of the cable being hooked up.
To assure easy dismantling of the two cables from the wall, the invention proposes that the cable ends, which preferably are fitted with plugs soldered onto the inner conductors, shall be connected using jacks receiving said plugs.
Lastly dismantling is made easy by adding detachable fasteners of the cables"" metal sheaths on the outer metal sheath.
This device of the invention offers the advantage allowing connecting high-voltage carrying coax cablesxe2x80x94where said voltages may reach and even exceed 100 kvxe2x80x94and to make use of such cables at very low pressures, and even in a deep vacuum that may be as low as 10xe2x88x927 mbars, this limit being set by the mechanical strength of the elastomer dielectrics in vacuum and the associated surface degassing, without electric discharges taking place at the junctions between the dielectrics.
Said device of the invention also allows making the connection without generating electromagnetic interference thanks to the shielding continuity around these elements.
Another advantage of the invention is that the proposed axial geometry of the opposite dielectric, namely the insulating sleeve dielectric and the insulating sheath dielectric of the cable, entails a connection inductance which is close to that of the cable and that consequently this kind of connection system assures the transmission of high-voltage electric pulses at minimal losses caused by counter-electromotive forces. By preserving the axial structure, the advantages of the low-voltage connection systems are thus retained.
Moreover the axial configuration offers the advantage that this connection takes place in a cylindrical volume of small diameter.
Lastly the device of the invention offers the advantage that with regard to its application as a wall feedthrough, it is easy to affix the cables to and remove them from the wall.

Connection system operating in vacuum for high-voltage currents

Abstract: This connection system comprises a grounded outer metal shell connected to the cables"" metal sheath and a dielectric insulating sleeve, said sheath and sleeve enclosing the cables to be connected, and said system is fitted with seals allowing subtending a sealed cavity between the cables"" insulating sleeve and insulating sheath.


Methods, compositions, and kits for labeling tetracysteine-tagged proteins with biarsenical fluorophores with increased specificity, including compositions, methods and kits particularly adapted for labeling of tetracysteine-tagged proteins to be resolved within an electrophoresis gel.

Recently, a new class of fluorophore derivatives of tremendous value in the detection, visualization, and purification of recombinant proteins has been introduced.
These biarsenical fluorophore derivatives, as adducts with EDT (1,2-ethanedithiol), are self-quenching: the small size of the EDT moieties permits free rotation of the arsenic atoms, which quenches fluorescence of the fluorophore. The essentially nonfluorescent molecule is rendered fluorescent by competitive displacement of the EDT moiety by a specific tetracysteine peptide motif (CCXXCC, (SEQ ID NO: 1) where "X" represents any amino acid), an engineered sequence that is uncommon in natural proteins; binding to the tetracysteine motif constrains motion of the arsenic atoms, unquenching the fluorophore. Griffin et al., Science 281:269 (1998); Griffin et al., Methods Enzymol. 327:565-78 (2000); Adams et al., J. Amer. Chem. Soc. 124:6063-6076 (2002); Gaietta et al., Science 503-507 (2002); U.S. Pat. Nos. 5,932,474, 6,054,271; 6,451,569; 6,008,378; U.S. patent application publication no. 2003/0083373, and international patent application publication no. WO 99/21013, the disclosures of which are incorporated herein by reference in their entireties.
Advantages of the biarsenical fluorophores as fluorescent protein labeling reagents include small size, ability of the EDT2 adducts to cross cell membranes, ability to recognize a binding domain that is sufficiently small as not to interfere substantially with the function of the protein to which it is fused, nanomolar (or lower) dissociation constant for binding to the tetracysteine motif, rapid conversion from a nonfluorescent to a fluorescent state upon binding, and the reversibility of its binding upon addition of a high concentration (millimolar) of EDT.
The biarsenical derivative of fluorescein that is most commonly used is 4′-5′-bis(1,3,2-dithioarsolan-2-yl)fluorescein-(2,2-ethanedithiol)2, known as FlAsH™-EDT2 or Lumio™ Green, and is available commercially (Invitrogen Corp., Carlsbad, Calif.). The red-fluorescing biarsenical resorufin derivative, known as ReAsH™ or Lumio™ Red, is also available commercially; methods of synthesizing other such biarsenical fluorophores, such as CHoXAsH-EDT2 and HoXAsH-EDT2 are described in the literature.
Tetracysteine biarsenical affinity tags (FlAsH™ tags) have been successfully incorporated at either the N- or C-termini of proteins, as well as exposed surface regions within a protein and have been used to permit visualization of recombinant proteins expressed within living cells, and in SDS-PAGE gels. Griffin et al. 1998, Griffin et al. 2000, Adams et al. 2002, supra.
In PAGE gels, inclusion of the FlAsH-EDT2 reagent in the sample loading buffer allows rapid detection of recombinant proteins in whole cell lysates using a standard UV light box without the need for western blotting or other more laborious protein detection methods.
Although the preferred tetracysteine motif occurs rarely in natural proteins, permitting specific labeling of proteins to which the tetracysteine motif has been recombinantly fused, FlAsH-EDT2 has been shown additionally to bind to endogenous cysteine-containing proteins, Stroffekova et al., Pflugers Arch.-Eur. J. Physiol. 442:859-866 (2001), which increases background fluorescence. Stroffekova et al. suggest that FlAsH™ binding to the vicinal cysteines in the C—X—X—C protein motif of endogenous proteins may limit the use of FlAsH-EDT2 to staining recombinant proteins expressed at a high level in cells with a naturally low background.
Given the advantages of biarsenical fluorophores as labeling and purification reagents for recombinantly tagged proteins, there is a need in the art for compositions, methods, and kits that permit tetracysteine-labeled fusion proteins to be labeled with biarsenical fluorophores with decreased reactivity with endogenous protein motifs. There is a particular need in the art for compositions, methods and kits that provide increased specificity of labeling of tetracysteine-tagged recombinant proteins resolved within electrophoresis gels.

Compositions, methods and kits for biarsenical fluorophore labeling


A method for repairing a perforation in a tympanic membrane comprising attaching a single patch to an undersurface of the tympanic membrane covering the perforation.

The present invention, in some embodiments thereof, relates to the field of Tympanoplasty and, more particularly, but not exclusively, to a device and a method for repairing a perforation in a Tympanic membrane.
Tympanoplasty is a surgical treatment for repairing a perforation in the tympanic membrane (commonly known as "eardrum") and defects in one or more of the ossicular bones. Perforations in the eardrum may be the result of a birth defect or may be attributed to ear/nose/throat infections, physical ear injury, exposure to high noise levels, aging, among other contributing factors.
Methods for repairing eardrum perforations and devices used in tympanoplastic surgery are known in the art.
U.S. Pat. Nos. 5,501,700 and 5,643,300 to Hirata relates to "an eardrum perforation patch and an eardrum undersurface scraper for application of the patch. The eardrum perforation patch comprises double plates connected together with a coupler and these elements are made of artificial material. The plates comprise a supporting piece and a closure piece. After being inserted into the tympanic perforation the closure piece pinches the perforation margin and it stays steadily in place until it changes to a new part of the tympanic membrane. The eardrum undersurface scraper comprises a shaft, a neck and a head with a blade edge. The neck is curved at an angle of more than 90 degrees, twisted and rotated, so that the blade edge gains access to target points behind the tympanic membrane and scrapes and entirely rakes out the mucosal barrier on the undersurface grafting bed of the tympanic membrane through the tympanic perforation. The combination of the eardrum perforation patch and the eardrum undersurface scraper is useful in repairing the tympanic perforation".
U.S. Pat. No. 5,236,455 to Wilk et al. relate to "a device for repairing a tympanic membrane comprises a patch provided on one side with an adhesive layer, and an elongate tubular applicator member having a proximal end and a distal end. The patch is removably attached via suction to the distal end of the tubular applicator member so that the adhesive layer faces away from the elongate applicator member. The proximal end of the tubular applicator member is temporarily closed or sealed to maintain the suction force, thereby bolding the tympanic patch to the distal end of the applicator tube while the tube is being inserted through the auditory canal. Upon a pressing of the patch against the ear drum so that the patch covers the perforation, the proximal end of the tube is released to pressurize the tube channel with ambient air. This pressurization releases the patch and allows it to adhere to the tympanic membrane".
U.S. Pat. No. 4,641,651 to Card discloses "an ossicular replacement prosthesis is configured to have its tympanic membrane-facing end self-attached to a cartilage plug forced there against. Self-attachment is achieved either by a prosthesis projection penetrating the plug, a prosthesis portion enclosing at least part of the plug, or adhesive attachment between the plug and prosthesis. A cartilage punch is provided which removes a cartilage plug of uniform thickness from a patient's tragus, retains the plug after removal and then forcefully urges the plug against the prosthesis to effect self-attachment. The punch includes a reciprocatable annular cutting member and a stage surface. Tragal cartilage is inserted between the cutting member and the stage, and the cartilage plug is cut and retained in the cutting member by forcing the cutting member toward the stage to pierce the tragel cartilage. The prosthesis is then placed on the stage so that the retained cartilage plug can be forced thereagainst by again translating the cutting member toward the stage".
U.S. Pat. No. 6,309,419 to de Juan, Jr. et al. discloses "a tympanic membrane prosthesis is provided that includes, in combination, a generally flat, planar membrane sized to overlay a tear or perforation in the tympanic membrane and having at least one preformed perforation, and at least one mechanical fixation device for fixing the membrane to the tympanic membrane of a patient. Each mechanical fixation device is a tack component including a sharp, piercing distal end, an enlarged proximal end and a shaft extending therebetween. A tack insertion device is provided to guide the tack to and through the tear covering membrane."
Additional background art includes U.S. Patent Application Publication No. 2002/0151974, U.S. Pat. No. 5,254,133, China Patent No. CN2162943, and Korea Patent No. KR20080040516.


A bit retention apparatus for the use of retrieving the hammer bit in cases of shankage. The apparatus incorporates a dual sleeve design that fits over the chuck and the extended head section of the hammer bit. The first, “inner” sleeve has two or more ring pieces that fit onto the chuck and have the retention ring fitted into the lower section of the sleeve. The second, “outer” sleeve fits onto the chuck over the inner sleeve to provide protect to the inner sleeve while pulling the shanked bit out of the well bore. Attachment to the bit is accomplished by collars, knobs, or threads on the interior of the sleeves that correspond with holding bands, retention rings, or threads on the bit and chuck.

1. Field of the Invention
Applicants' invention relates to the general field of downhole air hammers, also known as percussion drills, but also can be used in the fluid drilling sector when using the hammer assembly. More particularly, it relates to a bit retention apparatus designed to retain and retrieve a broken bit when breakage or "shankage" of the bit shaft occurs. The apparatus retains the broken bit and significantly decreases the chance of losing the broken bit while pulling the drill string out of the well bore.
2. Background Information
When using the percussion drilling assembly, bits can and may be broken due to the high energy levels and rotational torque loads they experience when in use. Along with these two stresses, metal fatigue can be a factor due to the constant impact of the percussion drilling tool. These catastrophic failures often lead to "fishing" jobs which use expensive techniques to retrieve the broken bit from the well bore. Often in these cases, the well bore must be cemented and additional costly measures used to go around the bit left in the hole.
The drill bit is of the type that has larger head section (including a cutting face) at one end; a smaller shank/shaft section on the other end that is used to mate with the Driver sub which delivers rotational energy from the drill string to the bit via splines; and a retaining means for holding the drill bit head to the percussive hammer between the two ends. The standard hammer bit features an external threaded section located just above the head section on the hammer bit. This thread is used when breakage of the bit occurs but still results in a fishing operation to retrieve the bit head. In order to retrieve this bit, one must attempt to "screw" a matching tool over the threaded area for means of retrieving the bit. This method is not only unpredictable, but still results in added expense to the operation.
Once the broken bit is "screwed on," drawing the broken bit from the well bore can still be a problem. Irregular geographical formations and soil/rock texture can cause the bit to twist and allow the possibility of the bit "unscrewing" while being pulled out of the hole. Thus, similar results can occur even once the threaded bit is attached. This can also happen with current retention systems that incorporate a bit that is pre-screwed on to the shank.
Not only do these above mentioned possibilities exist, other problems can also prevent the broken bit from being pulled out of the hole. For example, due to the abrasive characteristics of the geological formations being drilled through, current retention devices can experience washouts to the retention systems. If abrasion causes the retention device to fail, then the chances of retrieving the broken portion of the bit head reduces over time.
These patented ideas have been utilized in the case of retrieving the broken bit but each has flaws in the design.
In the U.S. Pat. No. 5,065,827 (Meyers, et. Al.), the threaded sleeve has been used for such drilling operations but due to the design concept, the broken bit has been "unscrewed" or "pulled" out of the tool while pulling out of the well bore. The percussion drilling tool is mainly used in deviation control and the possibility of the well bore being "cork screwed" can "unscrew" the broken bit from this system due to the string rotating even while chaining out of the hole. The term chaining out of the hole describes the tripping system where the drill string is being pulled with the table locked to prevent the turning, of the drill string. All rotation of the drill string takes place on the pipe being set back so as to remove it from the well bore. The remaining drill string is thus in suspension unable to move due to the power of the rig.
U.S. Pat. No. 4,726,429 (Kennedy; Feb. 23, 1988) describes a retention device which utilizes an extended driver sub and ball bearing mechanism to retain the bit head to the hammer.
U.S. Pat. No. 5,065,827 (Meyers et al; Smith international; 1991) utilizes a "Screw-On" version bit retention system which shows that the bit head could be retained by a external sleeve that was trapped between the Driver Sub (lower sub that has splines to mate with the bit shank for transmitting the torque of the drill-string to rotate the bit) and the hammer housing on its upper end and was threaded to/below the bit head's retaining thread. This first design has the limitation in that it is possible for the bit head to unscrew from the retainer during the trip out of the hole and thus allow the bit head to fall back to the bottom of the hole.
U.S. Pat. Nos. 5,647,447 and 5,699,867 (Jones; Ingersol-Rand; 1997) utilize a similar retaining sleeve (wear collar) that was trapped between the driver sub and hammer housing on the upper end and was attached to the bit on its lower end by a flexible retaining member (snap ring) that was removable from the assembly. This design had more of a positive retention capability of the Meyers design (above) but is difficult to assemble and disassemble in field applications.
WO Patent # 98/05476 (Moir & McInnes; SDS Digger; 1998) utilizes several split sleeve retainer designs that are also attached between the driver-sub and hammer housing on its upper end and below the bit circumferential shoulder on its lower end. These split retainers may be supported by an additional outer ring and/or sleeve to prevent the split sleeves from moving radially away from the circumferential retaining shoulder. In addition, this patent also shows a combination retainer sleeve and driver sub with extended fingers design which is assembled through milled slots in the retaining shoulder. The milled slots are used to allow assembly and to also prevent rotation of the bit to a position of which the retainer lugs will drop through the milled slots in the retaining shoulder.
U.S. Pat. No. 6,070,678 (Pascale; Numa Tool Co.; Jun. 6, 2000) utilizes a retainer sleeve which is attached between the driver-sub and hammer housing on its upper end and slides past the bit retaining shoulder. After the lower section of the retainer is in position below the bit retaining shoulder, pins are driven into the retainer which effectively prevent the retainer sleeve from moving up past the bit's retaining shoulder. These pins are "fixed" to the retainer until disassembly.
An additional patent for a retention system includes U.S. Pat. No. 6,021,856 (Pascale, Jack H.). While each of the above is unique in design, none of these provide the features of the current invention.
Thus, there is a need for a device for retaining and retrieving broken percussion drill bits. Further, it is advantageous for such a device to make connecting to the broken piece easy by retaining a connection, have a means for resisting disconnecting, and protecting the assembly as it is removed from the hole.

Percussion hammer bit retainer apparatus