This invention discloses a dynamic memory allocation method for an Ethernet switching architecture, which can resolve problems with the limitations of transmission bandwidths and transmission port counts in a conventional network packet switching. The method comprises steps of providing a plurality of input ports and output ports, providing a shared memory for storing packet segments of a plurality of packets, providing a first link RAM (Random Access Memory) for controlling a making and reading of a single linked list for the packet segments of each the plurality of packets, and providing a second link RAM serving as a FIFO (first in first out) device for co-managing an obtaining of the link address spaces at the corresponding input ports before the single linked list been made, and a releasing of the link address spaces at the corresponding output ports after the single linked list been read.

1. Field of the Invention
The present invention relates to a method for dynamically allocate memories in an Ethernet switching architecture. More specifically this invention relates to an Ethernet switching architecture provided with an optimized single linked list for dynamically allocate a shared memory through a free-link RAM during the packet receiving & transmitting process, in order to achieve the object of improving the transmission bandwidth of network switching.
2. Description of the Related Art
A shared memory architecture is one that uses a single common memory as a switching device for network packets between the input ports and output ports. Through the path of data receiving of an input port, a received packet can be stored on the shared memory and can be assigned and transmitted to the path of data transmitting of an appropriate output port. And it is often used as a main structure for LAN (Local Area Network) switching because of the advantages of lowering cost, simplifying design requirements, and enabling easy implementation.
A shared memory may be divided into a plurality of contiguous data buffers that each has a fixed-length of 2k bytes and used as a FIFO device to store the received packets from a plurality of input ports and to transmit the received packets to an appropriate output port. This is simple for hardware configuration, however, the length of the received packet could be considerably smaller than the fixed length and the usage efficiency would dramatically reduced.
To solve this problem, a shared memory is often configured as a plurality blocks of discontiguous data buffers with a fixed length of 256 bytes to store the received packet segments from a plurality of input ports. After the plurality of packet segments have been received from the input ports, the shared memory would then assign the free data buffers to the plurality of packet segments. At the mean time, a link RAM mapping to the shared memory would store the corresponding link addresses and a linked list of the block addresses of the plurality of packet segments. According to the block addresses, the corresponding link addresses, and the designated output ports of the plurality of packet segments, the plurality of packet segments will be inserted to a corresponding output queue of an appropriate output port. Here, the output queue represents the stream of packets waiting in the path of data transmitting to be transmitted to a corresponding output port.
FIG. 1 is a diagram simplified illustrating a conventional Ethernet switching architecture. As shown in the diagram, a shared memory 10 is configured to have a plurality of blocking data buffers 11 with same size. The shared memory consists of a free-buffer pool 12 and a plurality of assigned buffers 13. The free-buffer pool 12 stores blank blocks to be assigned to the packet segments 21 waiting to be received, and those been released from the plurality of assigned buffers 13 after the packet segments have been read. And the plurality of assigned buffers 13 store packet segments received from the plurality of input ports 20. Additionally, the number of link address spaces 31 on a link RAM 30 is configured to be the same as the block counts on the shared memory 10. The link addresses 33 and the block addresses 14 of the shared memory 10 are in a mapping relation 15.
For instance, the link addresses of a linked list 34 for the six packet segments of a received packet are #4, 6, 8, 9, 13 and 14 in FIG. 1. And the six packet segments are stored on the shared memory 10 with its mapping block addresses 14 at &50, 70, 90, 100, 110 and 140 respectively. The final link address #14 will be linked to the link address #10 of the first packet segment of a next received packet. As a result, a flag 35 representing the link address #14 pointing to the link address #10 will be assigned. The assigning also indicate that the corresponding block of the link address #14 stores the last packet segment of the received packet. On the other hand, the link addresses #0, 7, 11, 12, 15, 3 and 5 of a linked list 36, illustrated by a broken line on the link RAM 30 in FIG.1, represents the released link address spaces of the previous packets been read. And to which the blank blocks &5, 15, 25, 35, 45, 55, and 65 in the free-buffer pool 12 on the shared memory 10 are respectively corresponded. These released link address spaces are available for link use of the packet segments of the next received packet. And the corresponding blank blocks are available for storage of the packet segments of the next received packet. In an unicast situation, a packet is transmitted to a designated output port. At this point, each packet segment of a packet is inserted to an appropriate output queue 37 according to its designated output port 40 with reference of the linked list 34 in order to achieve the object of transmitting the packet from the output port 40.
There are four steps to be sequentially carried out on the link RAM during the receiving to transmission of several packet segments of a packet. The first step is to get link. That is to assign the unused blocking data buffers of a shared memory to the plurality of packet segments and determine the corresponding link address spaces on the link RAM. The second step is to make link. That is to make the link addresses of the plurality of packet segments linked to form a linked list. The third step is to read link, which is to read the linked list. And the fourth step is to release link. That is to release the corresponding link address spaces after the linked list has been read. The following descriptions will further explain the process regarding to the receiving and transmission aspects, separately.
From aspect of the receiving, the packet segments of a packet firstly get link address spaces 31 that are available through an input port 20 and then the packet segments are written in. Then a linked list 34 is made and inserted to an output queue 37 to complete a receiving of the packet segments. FIG. 2 is a flow chart illustrating one example of the controlling process in receiving a packet according to the conventional Ethernet switching architecture described in FIG. 1. Listed below are the descriptions of the controlling steps with reference to FIG. 1.
Step 201: To get six link address spaces. That is, an input port 20 judges whether the number of link address spaces available for use on the link RAM 30 is less than six. Keep getting link address spaces while the number is less than six; otherwise go to Step 202.
Step 202: To judge whether there is a packet to be received by the input port. Yes then go to Step 203, otherwise go to End.
Step 203: To receive packet. Start writing the packet into the first block of the mapping blocks (e.g. the blocks &50, 70, 90, 100, 140, and 150 in FIG. 1) on the shared memory 10 of the obtained six link address spaces (e.g. #4, 6, 8, 9, 13, and 14 in FIG. 1).
Step 204: To write in packet data. That is to write in the packet data according to the current link addresses 33 (e.g. #4, 6, 8, 9, 13 and 14 on FIG. 1) and the link on the link RAM 30 of the packet segments 21 of the packet, and the mapping block addresses 14 on the shared memory 10.
Step 205: To judge whether a packet has been completed written. Yes then go to Step 208, otherwise go to Step 206.
Step 206: To judge whether a block has been completed written. Yes then go to Step 207, otherwise proceed the next address writing on the shared memory 10 and go back to Step 204.
Step 207: Proceed to linking, loop back to Step 204 and proceed to the next block writing. The proceeding to linking comprises: Assign only the next link address to the current link address and no further linking when the block just been written in is doing the first link. Assign the next link address to the current link address and link the current link address to the previous link address when the block just been written in is not doing a first link.
Step 208: To judge whether the packet is a good packet. Yes then go to Step 209; otherwise reject to receive the packet, release the link address spaces 31 on the link RAM 30 for a next packet to be received, and loop back to Step 202.
Step 209: To judge whether there are enough buffers on an output port 40. Yes then go to Step 210; otherwise abandon the received packet, release the link address spaces 31 on the link RAM 30 for a next packet to be received, and loop back to Step 202.
Step 210: To judge whether the packet is the first packet destined to the output port 40. Yes then proceed to Step 212, otherwise go to Step 211.
Step 211: To make link. That is to insert the current linked list of the packet to the tail address 43 of the output port 40 and to write in the flag 35 of the final link address of the packet on the link RAM 30.
Step 212: To write in the flag of the final link address of the packet on the link RAM 30 and to inform the output port 40 the starting link address of the packet on the link RAM 30.
From aspect of the transmission, the block addresses of the packet segments are first read, and then respectively read the packet segments in turn and its linked list to complete the transmission of the packet segments. In the final, the corresponding link address spaces been read over are released. FIG. 3 is a flow chart illustrating one example of the controlling process in transmitting a packet according to the conventional Ethernet switching architecture described in FIG. 1. Listed below are the descriptions of the processing steps with reference to FIG. 1:
Step 220: An output port 40 judges whether there is a packet for transmission. Yes then proceeds to Step 221, No go to ends.
Step 221: To read the header address on the output queue. That is to read the header address 38 on the output queue37 of the output port 40 to get the first block address. In the meantime, proceed to the Step 222 and Step 223.
Step 222: To read links. That is to read the link addresses of the linked list 34 of the packet sequentially and proceed to Step 224.
Step 223: To read in packet data. That is to read in the packet data according to the current link addresses 33 of the packet on the link RAM 30, and the mapping block addresses 14 on the shared memory 10. Then jump to Step 227.
Step 224: To judge whether the link of the last block has been read. Yes then proceed to Step 225, otherwise loop back to Step 222.
Step 225: To judge whether there exists a next packet for transmission. Yes then proceed to Step 226, otherwise jump to Step 227.
Step 226: To load the address of the last block. That is to load the link address of the last block of the packet segments of the transmitting packet and use it as the header address for the next packet for transmission. Proceed to Step 227.
Step 227: To judge whether the packet for transmission either been completely read or abortively transmit. Yes then proceed to Step 228, otherwise keep on judging.
Step 228: To release link. That is to sequentially release the link address spaces 31 corresponding to the packet segments that have been read on the output port. Proceed to Step 229.
Step 229: To judge whether the entire link address spaces 31 on the link RAM 30 have been released. Yes then loop back to Step 220, otherwise back to Step 228.
As shown in FIG. 2 and FIG. 3, the four steps of getting link, making link, reading link and releasing link which the linked list of the packet get through are co-managed by only a link RAM 30 during the receiving to the transmission process. Owing to this, the time required for each packet from the receiving to transmission is the product of the time required to get through the four steps (4×clock period), the block counts and the transmission port counts used. In the 10/100 MB/s Ethernet switching, the bandwidth required might not be limited by the linked list method described above. However, in high speed Ethernet switching, under the demand of the transmission time for a packet to be smaller than 672 ns (that is, the bandwidth is 1 Gb/s and above), the transmission port counts that is proportional to the transmitting time of the packet would be limited.
Accordingly, methods for solving bandwidth problems have been proposed. And one is to shorten the time required for transmitting packet by increasing the clock frequency of the system and thus increasing the bandwidth. However, this will cause the power consuming and poor reliability problems. Therefore, finding a method that can obtain multiple ports and high bandwidth without increasing clock speed beyond the permissible range for Ethernet switching is very desirable.

Ethernet switching architecture and dynamic memory allocation method for the same


A method of identifying peptides of an antigen of interest which are capable of recognition by or induction of cytotoxic T lymphocytes, comprises the steps of: ascertaining a "motif" of peptides which bind to a chosen HLA class I allele; providing peptides having this motif which are present in the known sequence of the antigen of interest; screening the peptides using an HLA assembly assay; and screening the resulting peptides for recognition by or induction of cytotoxic T lymphocytes. The above peptides have been identified by this method, and the peptides and vaccines containing them are also claimed.

1. Field of the Invention
Human leucocyte antigens (HLA) play a pivotal role in cellular immune responses. They present peptides derived from various proteins to T lymphocytes: HLA class I molecules present peptides derived from intracellular, cytoplasmic, antigens to (CD8 positive) HLA class I restricted cytotoxic T cells [1], whereas HLA class II molecules present peptides derived from exogenous antigens to (CD4 positive) regulatory T lymphocytes [2].
2. Description of the Related Art
The precise definition of such peptide epitopes is of interest for understanding variation in immune responses between individuals, for identifying the pathogenic mechanisms of autoimmune disorders and for designing subunit vaccines. Recently, by eluting peptides from purified class I molecules, Rammensee and colleagues [3] and others [4] showed that particular HLA class I types bind short peptides of 8-10 amino acids in length. Furthermore, they found conserved amino acids at certain positions in the peptides bound to particular class I molecules which are characteristic of the individual HLA, and thereby defined "motifs" for the type of peptide that binds to a given HLA type. This suggests a means of identifying epitopes within previously known protein antigens by selecting short peptide sequences from that antigen that fit the peptide "motif" for a given HLA. However, it is likely that only a small proportion of peptides fitting such a motif are actually epitopes [5].
We have recently developed a novel assay [6], termed an HLA assembly assay, which provides a means of testing whether particular peptides will bind at high affinity to a particular HLA class I molecule, such as HLA-A2. Peptides which act as epitopes would be expected to bind to their particular class I molecule with high affinity, and we found that known HLA-A2 epitopes did so [6]. This suggested to us that combining the techniques of Rammensee et al. to identify conserved residue(s) in peptides binding a particular HLA class I with the HLA assembly assay to screen such peptides for high-affinity binding, would provide a rapid and novel approach to identifying peptides presented by HLA class I molecules that should include most or all HLA class I restricted T cell epitopes in that antigen. Then cytotoxic T cell assays may be undertaken using lymphocytes from individuals exposed to the micro-organism to identify which of the binding peptides are recognised as cytoxic T cell epitopes.

Plasmodium falciparum MHC class I-restricted CTL epitopes derived from pre-erythrocytic stage antigens


The present invention relates to a method of directing in situ oriented immobilization of a protein on a support. This method involves providing a support and contacting the support with a solution. The solution comprises (a) a protein comprising a coupling moiety and (b) a molecule comprising a first group reactive with the support and a second group reactive with the coupling moiety. The molecule binds (i) the support at the first group and (ii) the coupling moiety at the second group, thereby immobilizing and orienting, in situ, the protein on the support. Also described are a protein array and a method of screening compounds for protein interaction.

Protein microarrays are important tools for the discovery of biomarkers, protein-protein interactions, and protein-glycan interactions (MacBeath, "Protein Microarrays and Proteomics," Nat. Genetics 32:526-32 (2002); Krishnamoorthy et al., "Glycomic Analysis: An Array of Technologies," ACS Chem. Biol. 4(9):715-32 (2009)). Lectin microarrays are protein microarrays for the detection and analysis of cellular glycosylation (Pilobello et al., "A Ratiometric Lectin Microarray Approach to Analysis of the Dynamic Mammalian Glycome," Proc. Natl. Acad. Sci. U.S.A. 104(28):11534-9 (2007); Pilobello et al., "Development of a Lectin Microarray for the Rapid Analysis of Protein Glycopatterns," Chembiochem 6(6):985-9 (2005)).
The current approach of creating lectin microarrays is limited, in part, by glycan-detecting sensitivity as a function of protein concentration. Recently, a method to utilize bacterial lectins for glycomic analysis has been developed (Hsu et al., "A Simple Strategy for the Creation of a Recombinant Lectin Microarray," Mol. Biosyst. 4(6):654-62 (2008)). These lectins are recombinantly expressed as fusion proteins containing an N-terminal glutathione-S-transferase-("GST"-) and a polyhistidine-("His6"-) tag. Previous studies have shown that GST-fusion proteins can be oriented on a glutathione ("GSH") surface. Orienting lectins using the GST-GSH interaction on glutathione-treated slides was found to have a significant (>2-fold) increase in their activity. Although this was beneficial for a recombinant lectin microarray, a solely recombinant array means a significant loss of diversity in binding proteins on an array. Thus, one drawback of this approach is the requirement that all proteins to be displayed on the array have a GST-moiety. This means that only recombinant proteins can be utilized on a single array. It would be useful to also employ lectins (or other proteins) from natural (non-recombinant) sources.
In one approach, two distinct surfaces were created in a single subarray, displaying the benefits of orienting recombinant lectins which increased the sensitivity of the lectins to detect in the nanomolar (nM) concentration of glycoprotein (Propheter et al., "Fabrication of an Oriented Lectin Microarray" Chembiochem. May 18, 2010). This, compared to other methods of detection (such as evanescent wave detection), proved simple and inexpensive. The creation of a dual-surface array was also cost-effective. However, available probes are limited to recombinant lectins currently available. In the search for a methodology for the inclusion of oriented lectins to the standard microarray in which a single slide surface chemistry is utilized, a practical approach that is neither tedious nor expensive and is widely applicable to similar systems is needed.
The activity of proteins in protein microarrays is always a concern. For example, the random coupling of proteins via amide coupling chemistry to lysine residues often impinges upon protein activity, causing occlusion of active sites and in some cases denaturation of the protein structure. Control over the orientation of proteins is an important factor in enhancing activity on a solid support. However, in arrays, often there is also a desire to maximize the number of probes to be utilized. Thus, the limitations inherent in a recombinant array, i.e., that every protein has to be expressed with the same tag to be bound to a uniform surface, is undesirable if arrays that include proteins from a wide variety of sources are desired. Creating surfaces that can accommodate both recombinant and untagged proteins would enhance the utility and activity of current protein arrays.
The present invention is directed to overcoming these and other limitations in the art.

In situ oriented immobilization of proteins on a support


A multi-layer bus system includes an interconnect matrix, bus slaves, bus masters and a bus control circuit. The interconnect matrix has master connection ports and slave connection ports, and connects one of the master connection ports to one of the slave connection ports in response a control signal. The slaves are connected to the slave connection ports, respectively. The bus masters includes a priority bus master connected to one of the master connection ports and a non-priority bus master. The priority bus master generates a bus demand signal when it needs a real-time operation. The bus control circuit is connected between the non-priority bus master and the other master connection ports. The bus control circuit disconnects the non-priority bus master to the other master connection ports in response to the bus demand signal.

The present invention relates to the bus control circuit in a semiconductor integrated circuit and the bus control method, and the multi-layer bus system that used the AHB bus especially.
As to the conventional technology, there is described in "Multi-layer AHB Overview" (DVI0045 B, May 2004) published by ARM. The disclosed system includes two or more bus masters that are able to access simultaneously to two or more bus slaves. It is making such concurrent access possible, the bus zone as a system is extended, and system performance is raised.
In the conventional multi-layer bus system, the connection module for connecting two or more masters and slaves is performing processing which switches a layer (bus master) for every transaction with the round ROBIN system (namely, system which assigns a processing demand in order to two or more masters which performed the access demand), when an access demand occurs from two or more bus masters simultaneously to the same bus slave.
However, in the conventional multi-layer bus system, the system does not arbitrate for stopping other bus masters, like the conventional single layer bus system while a certain bus master operates, when two or more bus masters operated simultaneously. Therefore, there is a problem that reservation (a specific bus master should access the number-of-times bus slave of fixed in a fixed period) of the real-time operation of a specific bus master became difficult.
For example, in the multi-layer bus system having three layer composition, when the bus master of each layer advances an access demand to the same bus slave simultaneously, in order that the above-mentioned connection module may switch a layer (bus master) for every transaction of a bus slave (round ROBIN system), even if it is going to give priority and is going to access a bus slave for the real-time operation of a specific bus master. Since a layer changed by one transaction, access required for a fixed period of the bus master which needs a real-time operation was not completed, but it had the problem that a real-time operation became difficult. For this reason, there was the necessity of interrupting operation of the bus master of other layers by soft processing.
In the highly efficient system LSI for multimedia, there was much processing (a sound, image processing) of which a real-time operation is required, and when a multi-layer bus system was applied to such a system LSI, reservation of a real-time operation had become a problem.

Multi-layer bus system having a bus control circuit


An improved imaging apparatus is disclosed that allows a user to perform numerous imaging operations. The imaging apparatus may include one or more improvements to imaging box design to improve illumination control within the imaging box, such as improved door seal arrangements, improved door closing mechanisms, and improved light seals. The present invention may also include one or more improvements to imaging apparatus design to facilitate image capture, such as: an automated filter select device, a moveable stage, automated focus control, f-stop adjustment and stage height, and improved internal illumination for capturing photographic images.

One specialized type of imaging involves the capture of low intensity light—on the order of individual photons—from a light emitting sample. The source of the light indicates portions of the sample where an activity of interest may be taking place. For example, specialized in-vivo imaging applications may include analysis of one or more representations of emissions from internal portions of a specimen superimposed on a photographic representation of the specimen. The luminescence representation indicates portions of the specimen where an activity of interest may be taking place. The photographic representation provides the user with a pictorial reference of the specimen. Such imaging applications present particular challenges to the design of a box or chamber in which the sample is contained during imaging.
One particular challenge to imaging box design is the diverse lighting needs required during image capture. Photographic image capture typically requires the sample to be illuminated. Luminescent image capture requires substantially no light other than minute amounts produced within the sample. Conventional "light boxes", or "specimen chambers" have thus been developed to maintain the sample being imaged in relative darkness during luminescent image capture.
FIG. 1A is a fragmentary, rear elevation view of the inside of a latchable door 1 of a conventional light box, as seen from the interior of the box, showing a current latch mechanism 2. FIGS. 1B and 1C illustrate a seal 4 situated between the door 1 of FIG. 1A and the front wall of the box that the door is attached to. Collectively, the latch mechanism 2 and seal 4 allow a significant amount of light to enter the light box.
Thus, conventional imaging boxes or specimen chambers may not be adequate for many imaging applications, e.g., when the imaging involves the capture of low intensity light on the order of individual photons. In view of the foregoing, improved imaging apparatus would be desirable.


Collaborative-filtered content recommendations with justification in real-time is described. A recommendation system determines these recommendations, in part, by identifying digital content items of a catalog that are associated with a single attribute used to describe digital content. The attribute used for the identification is based on affinity scores computed for a client device user to which the recommendations are being provided. These affinity scores indicate the client device user's affinity for different attributes used to describe the digital content. Once the digital content items are identified based on the one attribute, the recommendation system is then limited to ranking and selecting from the identified digital content items to provide the recommendations. The recommendation system does not process the entire catalog of digital content items at once to rank and select the items. Due to this, the described recommendation system performs less computing and is therefore faster than conventional recommendation systems.

Advances in computing systems enable content to be produced easily and also to be distributed to end users through a variety of channels, e.g., different web sites, different applications on a variety of devices, and so on. As a result, the amount of content available to users is not only is staggeringly large, but also continues to grow. Given the amount of available content, users are unlikely to know about the entirety of this content. To this extent, recommendation systems provide digital content recommendations to users for items these systems predict the users will like. These recommendation systems provide digital content recommendations for a variety of items including, but not limited to, videos, music, audiobooks, e-books or periodicals, news articles, products or services, and so forth.
Broadly speaking, there are two types of conventional recommendation systems. The first type of recommendation systems are item-based. Item-based recommendation systems generally provide a same recommendation to different client device users that consume a same digital content item. For instance, if two different users view a same video, item-based recommendation systems recommend a same set of videos to watch next. This approach does not personalize recommendations, however. Typically, personalized recommendations lead to higher user engagement and retention than non-personalized recommendations. The second type of conventional systems, user-based recommendation systems, can provide personalized recommendations. In general, user-based recommendation systems learn a model for a given user's behavior, e.g., based on the given user's interaction history with digital content items, purchase history, and so forth. In particular, these user-based recommendation systems learn this model in the form of latent factors. While such latent factors capture some aspect of user behavior, the captured aspect is often computer, but not human, interpretable. Due to capturing aspects that are not human-interpretable, the recommendations of user-based systems cannot be provided with corresponding human-interpretable justifications that explain why the recommendations are provided. Though these recommendations recommend items that client device users may find more interesting than other items, if the recommendations are heeded, client device users may not be comfortable interacting with such recommendations because they lack corresponding justifications.
Accordingly, client device users may not interact with recommendations provided using these conventional techniques.

This patent is subject to a terminal disclaimer.


A braking device for an electric motor includes a rotor (10) and a stator, in particular for a direct current series wound motor and a brake element (20) which is movable between a braking position and an operating position; a brake shoe (30) that brakes the rotor (10) in the braking position is mounted on the brake element (20). The brake shoe (30) is mounted on the brake element (20) on the trailing end relative to the direction of rotation of the rotor (10).

The invention is based on a braking device for an electric motor.
From German Patent Disclosure DE 198 60 396 A1, a braking device for a direct current series wound motor is known that makes it possible to brake the rotor of the direct current series wound motor upon shutoff. To that end, the known braking device has a rockerlike brake element with a brake arm and a disengagement arm; the rockerlike brake element is pivotable between a braking position and an operating position. A brake shoe is secured to the brake arm, and the brake arm with the brake shoe is prestressed in the direction of the rotor by a compression spring and brakes the rotor in the braking position.
The disengagement arm of the rockerlike brake element, conversely, has the task of lifting the brake arm and the brake shoe from the rotor in operation so that the rotor can rotate freely. To that end, the disengagement arm and a yoke part of the stator form an air gap, so that when current is supplied to the stator winding, the disengagement arm is pulled against the yoke part, lifting the brake shoe from the rotor.
In the known braking device, the brake arm with the brake shoe is disposed on the rockerlike brake element on the leading end relative to the direction of rotation of the rotor, while the disengagement arm is conversely disposed on the brake element on the trailing end. This arrangement of the brake shoe on the leading end offers the advantage that the braking force acting on the brake shoe exerts a torque on the brake element, as a result of which the contact pressure generated by the spring is reinforced.


A collapsible structure has first and second panels, each panel comprising a top side, a foldable frame member having a folded and an unfolded orientation, and a fabric covering portions each frame member to form the panel for each frame member when the frame member is in the unfolded orientation. The panels are hingedly connected to each other along their top edges. An image is provided on the fabric of at least one of the panels, and a weight is coupled to the first panel.

1. Field of the Invention
The present invention relates to collapsible structures, and in particular, to collapsible structures which may be provided in a variety of shapes and sizes. The collapsible structures may be twisted and folded to reduce the overall size of the structures to facilitate convenient storage and use.
2. Description of the Prior Art
Collapsible structures have recently become popular with both adults and children. Examples of such structures are shown and described in U.S. Pat. Nos. 5,038,812 (Norman), 5,467,794 (Zheng) and 5,560,385 (Zheng). These structures may be twisted and folded to reduce the overall size of the structures to facilitate convenient storage and use. As such, these structures are being enjoyed by many people in many different applications.
For example, these structures have been provided in many different shapes and sizes for children's play inside and outside the house. Smaller versions of these structures have been used as infant nurseries. Even smaller versions of these structures have been used as dollhouses and action figure play houses by toddlers and children.
As another example, these structures have been made into tents or outdoor structures that can be used by adults and children for camping or other outdoor purposes. These structures have also been popular as beach cabanas.
Even animals can enjoy these structures. Some of these structures have been made into shelters that can be used by pets, both inside and outside the house.
The wide-ranging uses for these collapsible structures can be attributed to the performance, convenience and variety that these structures provide. When fully expanded, these structures are stable and can be used as a true shelter without the fear of collapse. These structures are easily twisted and folded into a compact configuration to allow the user to conveniently store the structure. The light-weight nature of the materials used to make these structures makes it convenient for them to be moved from one location to another. These structures also provide much variety in use and enjoyment. For example, a child can use a structure both indoors and outdoors for different play purposes, and can use the same structure for camping.


A side impact air bag (20) comprising: a lower portion for protecting the thorax region of an occupant, the lower portion including a neck portion through which inflation gas is received and a top portion which is sloped relative to a neck portion. An upper portion protects the shoulder and head regions of the occupant and extends generally perpendicularly from the lower portion.

The present invention generally relates to an occupant safety system and more particularly to a side impact air bag and system.
Accordingly the invention comprises: a side impact air bag having a lower portion for protecting the thorax region of an occupant; the lower portion includes a neck portion through which inflation gas is received and a top portion which extends away from the neck portion at an angle other than zero degrees with the horizontal. The upper portion is used to protect the shoulder and head regions of the occupant, and extends outwardly from the lower portion. In the preferred embodiment of the invention the upper portion extends outwardly at about 90 degrees from the top of the lower portion.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.


A disposable pathogen barrier of a material which is highly elastic and stretchable, yet tear-resistant, and capable of being placed in proximate contact and covering an entirety of a variety of elongated, tubular-shaped intra-oral medical or dental tools or implements which emit lightwaves in pre-determined ranges without distorting, interrupting or shifting the wavelength of the emitted light, or the receiving of reflected light, by the use of, in a first embodiment, an optically transmissive end and, in a second embodiment, an optically clear film to provide the required range of transmissivity of light.

Dental practitioners have been aware for years that the repeated handling of a dental tool by gloved or ungloved hands after either the dental practitioner's or the hygienist's hands have been in or around the mouths of several different patients without proper sterilization can bring about the spread of contagious diseases. Such contagious or communicable diseases are borne in or on the body fluids and/or tissues which may become attached to the tool or to the exterior surfaces of the gloved or ungloved hands of the dental practitioner or hygienist and then transmitted to the dental tool or implement, such as an intra-oral camera or an ultraviolet curing light, through contact. More recently, the spread of the hepatitis virus and the acquired immune deficiency virus have caused great concern among dental practitioners, dental hygienists and other staff members not only for their patients, but also for their own health and well-being.
The hepatitis virus and the acquired immune deficiency virus have been found to be carried in or on body fluids and/or tissues. In the environment in which dental practitioners, hygienists and dental staff members work, i.e. inside the mouth, bodily fluids such as saliva, blood, tissues comprising the gum and portions of the teeth, the pulp and root, etc. may potentially transmit the virus form through contact. The process of cleaning and/or repairing teeth by filling caries, performing a root canal procedure or performing restorative or cosmetic dentistry requires the drilling of the teeth and the subsequent scattering of tissue particles and body fluids about the mouth.
During restorative and cosmetic dental procedures, an intra-oral camera may be inserted into the mouth in order to view particular areas within the mouth which are difficult to view, or which can be seen more clearly through the enlargement provided by the monitor attached to the camera. It is also possible that during restorative and cosmetic dental procedures an ultraviolet curing light may be inserted into the mouth of the patient in order to effect the polymerization of the materials utilized in the restorations of the teeth. Some of the particles and/or fluids which potentially carry disease causing organisms may become attached or adhered to the gloved or ungloved hand of the dental practitioner, hygienist or other dental staff member, or to the unsheathed exterior of the intra-oral camera or the curing light. While it is possible to remove and discard the protective gloves, cleaning and sterilizing the exterior of sensitive electronic or narrow band illumination devices such as the intra-oral camera and ultraviolet curing light, between use on patients has become a serious problem because of their specialized construction.
During dental procedures ranging from cutting and shaping teeth for receiving caps and/or more extensive bridge work and restoration, or the newer cosmetic dentistry using certain polymers to build up or repair the teeth, the ultraviolet curing light may be placed into the interior of a patient's mouth in close proximity to the tooth or teeth being repaired to effect the curing (or polymerization) of the polymer materials used to restore the tooth or teeth through the use of certain visible lightwaves, i.e. infrared range illumination. The light guide portion of the curing light is placed into the patient's mouth by the dental practitioner or other staff member in order to effect the desired curing of the restoration and repair material.
The problem of disease transmission occurs as the curing light is replaced in its holder for subsequent use, possibly on a different patient, without attention to cleaning and sterilization. Anything the light guide may have come into contact with while in the patient's mouth may have become attached to the light guide and be transmitted to the next patient on whom the curing light is used. The mere swabbing down of the light guide with a disinfecting solution will not sterilize the curing light, nor will it kill all of the bacteria and virus forms which may have become attached thereto.
The same is true for an intra-oral camera, containing a dental illumination lamp, which is used by the dental practitioner to illuminate and view, on the associated enlarged video monitor, particular areas of the patient's mouth. Because of the long, narrow tubular construction of the intra-oral camera, and its use either during, intermediate, or subsequent to certain procedures within the patient's mouth, whatever may have been dislodged in the form of tissue or other tooth material or in the form of bodily fluids may become adhered to the exterior of the intra-oral camera and be transmitted to the next patient on whom the camera may be used. As in the earlier case, the swabbing down of the exterior of the camera body with a disinfecting solution will not sterilize it nor will such swabbing kill all of the bacteria and virus forms which may have become attached thereto. The same will be true for a dental illuminating lamp having similar construction (but without the video capabilities) used for illuminating the work place within the patient's mouth.
There have been some attempts to provide sterile sheaths for other dental tools, i.e. the dental handpiece or drill. U.S. Pat. No. 4,266,935 Hoppe! and U.S. Pat. No. 4,728,290 Eisner, et al.! provide apparatus which are particularly adapted for use with the dental hand pieces in use today. Neither of these devices address the problem of sheathing either the dental curing light or the intra-oral camera with a sterile shield or barrier which prevents pathogenic contamination but permits the visible lightwaves to be emitted without interruption or wavelength shifting.
There have also been attempts to provide sheaths to other dental or surgical implements, which sheaths provide protection against carrying bacteria and/or virus forms onto the exterior surfaces of the particular implements or tools. U.S. Pat. No. 3,794,091 Ersek, et al.! discloses a sterile sheath for enclosing an elongated surgical illuminating lamp (endoscope) with a light transmitting lens means disposed at the tip of the light transmitting shaft of the lamp structure. The sheath of Ersek is required to be made of a thermoplastic, thermosetting film in order to provide the necessary durability, rigidity and transparency required of the device. Because the sheath may be inserted through fairly long body canals, the sheath is required to exhibit the described characteristics in order to go around or through obstructions, be sufficiently flexible to bend around turns, curves or corners, yet still retain sterile integrity so that the sheath or barrier is not breached.
Another attempt is that made by U.S. Pat. No. 4,757,381 Cooper, et al.! which describes a sheath for placement over and around a dental camera. However, the Cooper device does not snugly overlie the dental camera and requires attachment by rotationally twisting the sheath and securing it at either end of the dental camera so that the twisted and rotated sheath remains in that position to achieve the prevention of cross-contamination from patient to patient from subsequent uses of the dental camera. The disclosure particularly describes a transparent, clear plastic material which is used to cover the dental camera, but which material does not exhibit any significant elasticity or strength beyond that necessary to resist minimal tearing when the rotating and twisting motion is utilized to secure the sheath in position.
An attempt to provide a transparent cover to a light ray radiation device was made in U.S. Pat. No. 4,804,240 Mori!. The description indicates that the cover member which covers the light radiator having a hat-shaped elastic body which is capable of transmitting the visible light ray components transmitted into the optical conductor cable. The cover member, although made to be disposable, may be cleaned and disinfected for repeated use. Since the disclosure describes the cover member being made from a transparent and resilient material, and that the cover member as a swordguard-shaped portion (as shown in FIG. 2a) which guard retains its shape, the cover member must be non-elastic.
With all of these earlier patents, there lacks an enabling disclosure which describes for an elastic sheath or barrier which can be superextended over the exterior surface of a dental tool or implement used in dental or medical procedures which can simultaneously provide the transmissivity for pre-determined light wavelengths while maintaining the cross-contamination barrier for the named pathogens.
The dental curing light and/or the intra-oral camera and illuminating lamp (as well as other medical devices) are not usually thought of as disease transmission devices. They are customarily cleaned with a disinfecting agent, but not sterilized in the normal course. Some of the light guide elements of curing lights or dental cameras and illuminating lamps are detachable for sterilization in an autoclave. However, detachment and reattachment for purposes of sterilization is not believed to occur with the frequency required (between each patient) as is done for other dental tools and instruments which may be sterilized in an autoclave. Hence, sterilizing most likely does not occur between patients and current practice would lead one to believe that only a disinfectant swabbing of the curing light or camera or illuminating lamp may be done between contact with patients to prevent cross-contamination.
In recent years, dental practitioners, hygienists and others in both the dental and medical professions have become increasing aware of the rapid spread of communicable diseases borne on body fluids and tissues such as may be dislodged and become attached to dental implements or the gloved or ungloved hands of dental or medical practitioners, hygienists, nurses or other staff members during procedures being performed within the body of a patient. In fact, dental and medical practitioners, along with their respective staff members, have been cautioned to protect themselves from infection by using sterile gloves and masks, and to use protective glasses, when practicing dentistry or other dental procedures on their patients. Recently, the rapid spread of the hepatitis virus and the acquired immune deficiency virus has caused significant concern among these practitioners. The American Dental Association and American Medical Association, as well as other professional organizations, have strongly urged that health care practitioners and their staff members take additional steps to decrease the chance of spreading disease by cross-contamination through the use of non-sterile implements.
It is, therefore, an object of the present invention to provide a protective pathogen barrier for tools or implements which may be inserted into the mouth or body of a patient which emit light in a pre-determined wavelength to significantly reduce or prevent the spread or cross-contamination of contagious, communicable diseases.
It is a further object of the present invention to provide such a barrier which is disposable after a single use and which is easily applied and removed so that it would have wide-spread acceptance in the dental and medical professions.
It is another object of the present invention to provide such a barrier which is highly elastic and stretchable, yet tear resistant, and which is capable of covering the entirety of a variety of elongated, tubular-shaped dental tools or implements which emit lightwaves in pre-determined ranges without interrupting or affecting the emission of such light, or the receiving of reflected light, by use of a lens means to provide the required transmissivity of light during dental or medical procedures.
Other objects will appear hereinafter.

Pathogen barrier with optically transparent end


A selective call receiver (111) has a first mask (134A) stored within the selective call receiver (111) indicative of a first period of reception for receiving a transmitted communication signal (99) having a plurality of packets (100). Each of the transmitted packet (100) has message information (110). An identifier (106) identifies the packet (100). The control signal (108) is representative of a second mask (134B) indicative of a second period of reception. The second mask is compared with the first mask for determining the second period of reception of the selective call receiver (111). A correspondence between the first and second masks determines whether to change the first period of reception of the selective call receiver (111) for receiving at least one additional packet.

Prior art selective call receiver systems (paging systems) have endeavored to efficiently communicate information to selective call receivers (pagers) while providing for effective battery saving operation of the selective call receivers. The widely accepted Golay Sequential Code (GSC) provides an asynchronous method for communicating message information to selective call receivers and has been described in U.S. Pat. Nos. 4,424,514 and 4,427,980 both issued to inventors Fennell, et al. The GSC protocol provides a preamble signal which initially synchronizes the selective call receivers to a paging signal. One of the several well known preamble signals may be used, each identifying a different group of selective call receivers which are used to decode following message information. Additionally, U.S. Pat. No. 4,860,003 issued to DeLuca, et al. describes power conservation during the reception of a signal, such as the GSC signal, in response to a signal indicating the occurrence of address information.
An asynchronous/synchronous signalling system has been defined by the Post Office Standardization Code Advisory Group (POCSAG). The operation according to the POCSAG signalling system requires selective call receivers to synchronously decode the received signal subsequent to being synchronized to the POCSAG signal. The POCSAG signal and a method for decoding the signal is described in U.S. Pat. No. 4,663,623 issued to Lax, et al. Like GSC, a POCSAG transmission may begin asynchronously with respect to a prior POCSAG transmission, and once the transmission begins, the signal is synchronously decoded until the transmission ends. The POCSAG transmission has at least one batch, each batch beginning with a synchronization signal followed by eight frames, each frame occurring at a predetermined time after the synchronization signal. A selective call receiver synchronized to the signal needs to search for its address in only a predetermined one of the eight frames. In the remaining seven frames, the selective call receiver conserves power by one of the well known techniques of battery saving. However, subsequent transmissions, for example, the POCSAG signals, need not be either bit or frame synchronized to the previous POCSAG transmission. By permitting a subsequent transmission signal to be synchronized only with each transmission, and not by bit or frame synchronization, the subsequent transmission is asynchronously synchronized to the POCSAG signal.
Most paging protocol signals are designed to co-exist with other paging protocol signals. For example, a GSC transmission may be followed by a POCSAG transmission which may be followed by a 5-tone sequential transmission, etc. It is desirable to provide battery saving features for the selective call receiver during the absence of a signal being directed to the selective call receiver. This has typically been accomplished with a preamble signal preceding the message transmission. Both the GSC and POCSAG signals begin with a long preamble signal providing for selective call receiver synchronization before the message transmission and providing for battery saving in the absence thereof. The preamble signal although providing for battery saving and synchronization, decreases the overall system message throughput. During the time taken for a preamble transmission, no message information is being communicated to the selective call receivers, thereby decreasing throughput of the system.
Synchronous selective call receiver protocols eliminate any preamble signal, thereby enabling a more efficient battery savings. A synchronous paging signal is shown in U.S. Pat. No. 4,642,632 issued to Ohyagi, et al. This synchronous signal has selective call receivers divided into one of a plurality of group fields, each group field occurring at a predetermined period and having a predetermined maximum message information capacity. Since the synchronous signal is always being transmitted, no preamble signals are required, and a selective call receiver needs only decode paging information while its preassigned group is being transmitted. However, varying traffic demands (the amount of message information for a group of selective call receivers) may cause the amount of message information for one group of selective call receivers to exceed the maximum capacity of the group field while another group field has available capacity. This causes transmission of idle signals during one group field, while in another group field, numerous messages are being queued because its capacity is exceeded. The throughput of the overall system is decreased because selective overload patterns are generated from the varying traffic levels within different group fields.
Thus, what is needed is a selective call receiver system which selectively sacrifices battery saving improvements afforded by a synchronous paging signal to prevent or to reduce overload occurring within the selective call receiver system.


A method for synchronizing a distributed multiple clock system in which the first clock to reach a first predetermined number of counts generates a polling request signal. The remaining clocks compare the content of their counters to determine if they are in synchronization with the clock that generated the polling request signal. Each clock will place itself inactive if it determines it is out of synchronization with the active clocks. The first active clock to reach a second predetermined number of counts will generate a synchronization interrupt signal which resets a counter in each clock to zero. A start subroutine readmits inactive clocks when after a synchronization interrupt signal is generated its counts are within a predetermined readmittance range or its counter counts up to a third predetermined value.

1. Field of the Invention
The invention is related to distributed clock systems and, in particular, to a method for synchronizing a distributed multiple clock system in a fault tolerant manner.
2. Prior Art
Various methods for synchronizing distributed clock systems are known in the art. Avsan et al, in U.S. Pat. No. 3,761,884, discloses a synchronization method in which all of the clocks in the system are reset when the fastest clock reaches a predetermined count. In contrast Smith, in U.S. Pat. No. 3,932,847, teaches a time-of-day clock synchronization system in which each out-of-sync clock is detected, then restarted using a synchronization program to be in sync with a selected one of the clocks that are in synchronization. Alternatively, Whiteside, in U.S. Pat. No. 4,330,826, discloses a synchronization system in which synchronizer modules receive sampling number messages from a plurality of computers. A find sampling number agreement module generates a voted sampling number and a sampling period timer is adjusted to synchronize its period with the voted sampling number Jensen et al, in U.S. Pat. No. 4,229,792, discloses a synchronization system in which each received message has a time slot number which is compared with the current time slot number of the receiving unit to establish synchronization. Further, Glenn et al in U.S. Pat. No. 4,392,196 discloses a synchronization system in which a time window is generated by a time alignment controller and, if the local pseudo time accumulator of each clock is within the time window, it is allowed to operate.
Each of these systems have particular advantage for particular application. For example, the synchronization system taught by Whiteside et al is for a fault tolerant multiple computer system and therefore synchronization also has to be fault tolerant. Synchronization is achieved by voting to obtain an average time value. Then the clock in all of the computers in the system are reset in accordance with the voted time value. Disclosed herein is a synchronization system for distributed clock which has no central clock, is fault tolerant and can achieve synchronization from any initial state.

Distributed multiple clock system and a method for the synchronization of a distributed multiple system


To check a digital signature, using a microcircuit card, the microcircuit being designed to receive and to process requests to check digital signatures, the process comprises storing in a memory in the microcircuit a certificates table containing digest forms of authorized public keys, and a phase of checking a digital signature consisting of: receiving by the microcircuit the digital signature to be checked and a public key corresponding to a private key that was used to generate the digital signature to be checked; calculating a digest form of the received public key, searching for the calculated digest form of the public key in the certificates table, and decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table.

This invention relates to a method and system for checking digital signatures and a smart card for using this method.
In particular, but not exclusively, it is applicable to authentication of information and verification of digital signatures in order to authorize specific processing. This processing consists particularly of recording rights in a card with an electronic microcircuit, for example in electronic transport ticket, or electronic purse or reduction voucher distribution applications.
Cards with electronic microcircuits, called smart cards, are usually used as a mobile computer support for a wide variety of applications mostly requiring a high degree of security, and particularly bank operations, secure payments, access to buildings or secure areas and telecommunications.
For example, when it is required to update sensitive data in a smart card, such as a refill amount for an electronic purse application, the card must be capable of checking the source of an update order that it receives. This is done by associating the update order with a digital signature, in which the identity of the signatory is guaranteed by a certificate that is also associated with the update order.
A digital signature added to a message is usually obtained by applying a hashing function to the message to obtain a digest, and encrypting this digest using a private key known only to the signatory. Therefore, all that is necessary to check a signature is to have the public key corresponding to the private key used, and the hashing function, to apply the hashing function to the message, to decrypt the signature using the public key and to compare the result obtained using the hashing function with the result obtained by decryption. If these two results are identical, the signature is correct.
A public key certificate, for example conforming with the X509 or PKCS#6 standard, is composed of a combination of a public key used by a person, identification information for this person and a definition of a validity period, the combination of this information being made impossible to falsify by a digital signature added by a certification authority, this signature using a private key of the certification authority. All that is necessary to check this certificate is to have the public key of the certification authority corresponding to the private key used, and to use this public key to check that the digital signature really is issued by the certification authority. It is thus possible to make sure that a public key corresponds to the identity of a determined person. However, this principle does not guarantee that the person who is using the private key corresponding to the public key is actually the person identified in the certificate. Certification authorities usually do not guarantee this correspondence.
To guarantee such correspondence, it has been proposed to set up a chain or pyramid organization based on the "certificates chains" concept in which the digital signature of each person is certified by the signature of an entity that was previously certified by another entity and so on, until reaching a reference authority located at the top of the pyramid. In such an organization, a signature is based on all certificates of all public keys in order to work upwards along the certification chain as far as the reference authority. Therefore to check a signature, all certificates have to be checked until reaching a certificate issued by a known entity in the certification chain. It is also necessary that the public key of this known entity should be stored reliably and so that it cannot be falsified.
The techniques that have to be used to manage such an organization can easily be installed in a PC type personal computer, particularly using Internet browsing software that integrates all or some of these functions with the SSL (Secure Sockets Layer) and HTTPS (Hypertext Transfer Protocol integrating SSL) protocols. However, these techniques are much more difficult to use in a smart card that has a significantly more limited calculation power and storage capacity. Certificates chains that have to be processed are very long compared with the usual characteristics of smart cards. Thus, a certificate conforming with the X509 standard may be several kbits long, and if the certificates chain is long, the card must be able to process and memories more information than is possible based on its capacities.
In this respect, it is important to emphasize that the terminal to which the card is connected cannot execute such a processing, and the terminal memory cannot be used for this processing, without affecting security since it would then be very easy to deceive the card, particularly by replacing one public key by another.
It has already been proposed to introduce all public keys of certification authorities in the certification chain, into the memory of the smart card. However this solution requires large memory capacities considering that the public key frequently occupies more than one kbit. It is also necessary that these public keys should be stored in a secure memory area to prevent risks of fraud consisting of introducing an unauthorized key into this list of public keys. At the moment, microcircuits installed in the smart cards do not have sufficient secure memory capacity.

Method and system for checking digital signatures and card with microcircuit for using the method


A collection tank for use in a vacuum operated earth reduction system, the collection tank comprising a closed first end, an open second end defining a tank sealing flange and a body extending between the closed first end and the open second end. An internal chamber defined by the body, the closed first end and the open second end has a door coupled to the open second end and is configured to releasably seal the open second end. An automated door closer is coupled to a center of the door, wherein the automated door closer provides a closing force at the center of the door so that the closing force is equally distributed about a periphery of the door to seal the door against the tank sealing flange.

With the increased use of underground utilities, it has become more critical to locate and verify the placement of buried utilities before installation of additional underground utilities or before other excavation or digging work is performed. Conventional digging and excavation methods such as shovels, post hole diggers, powered excavators, and backhoes may be limited in their use in locating buried utilities as they may tend to cut, break, or otherwise damage the lines during use.
Devices have been previously developed to create holes in the ground to non-destructively expose underground utilities to view. One design uses high pressure air delivered through a tool to loosen soil and a vacuum system to vacuum away the dirt after it is loosened to form a hole. Another system uses high pressure water delivered by a tool to soften the soil and create a soil/water slurry mixture. The tool is connected with a vacuum system for vacuuming the slurry away into a collection tank. The tank may then be emptied by opening a door on the tank.
Prior art vacuum systems are provided with a tank having a manually closing door that is locked in a closed position by latches, locks or other suitable locking mechanisms. Such devices rely on an operator to apply the proper amount of force to ensure that a tight vacuum seal is created between an outer periphery of the door and the edge of the tank. However, if the locking force is applied at two opposing edges of the door or to a single point around the periphery of the door, then the closing force is greatest at the point where the door is locked closed. In an example where the locking points are positioned at 9 o'clock and 3 o'clock on the door, the greatest closing force occurs at 9 and 3 o'clock with the least closing force occurring at 12 and 6 o'clock. That is, as you move away from the locking points, the closing force on the periphery of the door begins to decrease. While a vacuum seal may be created, it cannot always be guaranteed especially if the door is warped.


A sheet feeder which feeds a sheet in a sheet storage case includes a sheet storage case in which a sheet is stored, a dehumidifier which dehumidifies air, an air tank in which air dehumidified by the dehumidifier is stored, shutters and which bring the air tank and the sheet storage case into communication and out of communication, and fans and which send air between the air tank and the sheet storage case. The shutters and the fans are operated in accordance with humidity in the sheet storage case.

1. Field of the Invention
The present invention relates to a sheet feeder which feeds, from a storage case in which a plurality of sheets are stored, the sheets one-sheet by one-sheet, and the invention also relates to an image forming apparatus having the sheet feeder.
2. Description of the Related Art
When an image forming apparatus is used under a high humidity environment, transfer sheets stored in the apparatus absorbs humidity. Since transfer sheets which absorb humidity in a state where they are stacked in the apparatus absorb each other, there is a fear that sheet feeding failure is caused. Further, even if sheets can be fed, since insulation resistance is largely deteriorated, transferring ability of toner image is deteriorated and a failure image is prone to be generated.
To prevent a sheet from absorbing humidity, it is conventionally proposed a method in which a peripheral temperature of transfer sheets is increased to prevent the transfer sheets from absorbing humidity. As this method, there is a method in which under the high humidity environment, a dehumidification heater for increasing a temperature of a tray on which transfer sheets are stacked or a temperature of air in the apparatus is provided, thereby preventing the transfer sheets from absorbing humidity.
According to such a method, it is necessary to pass a current through the dehumidification heater and it is waste of electricity. Thus, there is also proposed to use a dehumidification unit including chemical absorbent (Japanese Patent Application Laid-open No. 9-44063).
There is also proposed a technique for conditioning humidity using a dehumidification member which can be thermally regenerated. According to this method, a desiccant type dehumidifier in which the dehumidification member absorbs humidity, the dehumidification member is heated and dried so that absorbed humidity is removed and the dehumidification member is regenerated is disposed in an image forming apparatus (Japanese Patent Application Laid-open No. 2005-77762).
According to the method using the dehumidification heater, however, it takes time to warm the peripheral environment of transfer sheets. In addition, even if the peripheral environment is warmed once and humidity of the transfer sheets is removed, if the sheet storage case is pulled out for adding transfer sheets or the like, outside air having high humidity enters, and it also takes time for again removing humidity from the transfer sheets which absorbed humidity. Therefore, there is a problem that it takes time before sheet feeding operation is started.
The method in which the desiccant type dehumidifier is incorporated in the image forming apparatus also has a problem that the dehumidification operation can not be started immediately before the dehumidification member is thermally regenerated, and it takes time for dehumidifying the transfer sheets.

Sheet feeder and image forming apparatus


An integrated circuit device has a plurality of active devices which are formed on a semiconductor body. A plurality of narrow isolating regions of insulating material are vertically formed on the semiconductor body such that at least one of the narrow isolating regions separates and thereby isolates adjacent active devices. Essentially all of said isolating regions are substantially equal in width, preferably less than or equal to about 0.5 .mu.m.

1. Field of the Invention
The invention relates generally to an integrated circuit (IC) isolation structure and more particularly to limited width trench isolation structures which are used to isolate devices of an IC.
2. Description of the Related Art
Various isolation structures are available to isolate devices in integrated circuits. One isolation structure, developed using a conventional method known as trench etch and refill, is shown in FIG. 1. In the conventional method, trenches 61-63 are etched in respective field regions 120 and 220 of the active devices 100 and 200 and subsequently filled with a CVD oxide 50 to isolate the active devices 100 and 200.
One problem with the conventional method is that a phenomena known in the art as "dishing" occurs in the oxide regions above the trenches 61-63 during the formation of the isolation structure. The "dishing" of the oxide 50 is represented by non-planar surface of the oxide 50 in FIG. 1.
The conventional method is illustrated in further detail by FIGS. 2A-2F. A pad oxide layer 11 is thermally grown on the surface of a silicon substrate 10 having well regions 130 and 230 as shown in FIG. 2A. Next, a layer of CVD silicon nitride 12 is deposited on top of the pad oxide layer 11 as shown in FIG. 2B. A photo-resist mask layer (not shown) is then deposited on top of the nitride layer 12 and the region of the nitride layer 12 exposed through the mask layer is anisotropically dry etched to produce etched openings 14 through the nitride layer 12 (see FIG. 2C). The etched openings 14 define field regions which are subsequently etched to form isolation trenches 61-63 illustrated in FIG. 2D (also shown in FIG. 1). The remaining portions of the nitride layer 12 function as a mask during the etching step.
After the trench formation, a CVD oxide layer 50 of a thickness H, where H>thickness of the nitride layer 12+thickness of the pad oxide layer 11+the height of the trench 62, is deposited above the remaining portions of the nitride layer 12 and the trenches 61-63. Basically, the main criteria is to make sure that the level of the CVD oxide layer 50 is above the level of the nitride layer 12.
The step of depositing the CVD oxide layer 50 is followed by a planarization technique. One technique may be direct polishing. The resulting structure after the step of polishing is illustrated in FIG. 2F which shows that the level of the oxide 50 at the center portions of the trenches 61-63 are lower in height than at the edge portions of the trenches 61-63. This phenomena is what is known in the art as "dishing" and, as shown in FIG. 2F, adversely affects the planarity of the IC.
An alternative conventional method is illustrated in FIGS. 3A-3H. Steps associated with FIGS. 3A-3E are identical to the steps described with respect to FIGS. 2A-2E and will not be repeated here. Planarization in the alternative conventional method is carried out by the use of a planarization mask 51 as shown in FIG. 3F. After the planarization mask 51 is applied, the CVD oxide layer 50 is etched and the planarization mask 51 is removed. The resulting structure is illustrated in FIG. 3G. The structure of FIG. 3G is then polished to yield the structure of FIG. 3H, which again shows the effect of "dishing."

Narrow width trenches for field isolation in integrated circuits


A bonding technology is disclosed that can form an anodic, conductive bond between two optically transparent substrates. The anodic bond may be accompanied by a Second bond, for example a metal alloy, solder, eutectic and polymer bond. The two bonds may be used for the same or a different purpose, and may be selected for the following attributes: hermeticity, electrical conductivity, low RF loss, high adhesive strength, leak resistance, thermal conductivity. The attributes for each bonding technology may be the same, or they may be different.

This invention relates to a methodology for bonding together two microfabrication substrates.
Microelectromechanical systems are devices which are manufactured using lithographic fabrication processes originally developed for producing semiconductor electronic devices. Because the manufacturing processes are lithographic, MEMS devices may be made in very small sizes. MEMS techniques have been used to manufacture a wide variety of transducers and actuators, such as accelerometers and electrostatic cantilevers.
Because MEMS devices are often movable, they may be enclosed in a rigid structure, or device cavity formed between two wafers, so that their small, delicate structures are protected from contamination or atmospheric conditions. Many MEMS devices also require an evacuated environment for proper functioning, so that these device cavities may need to be hermetically sealed after evacuation. Thus, the device cavity may be formed between two wafers which are bonded using a hermetic seal, which encloses the MEMS device in a protective and well controlled environment.
Microfabricated optical devices, such as emitters, reflectors, absorbers, gratings, and the like also exist. They may use or manipulate electromagnetic radiation, Such optical devices may require encapsulation in an optically transmissive device cavity to function effectively. Glass wafers would provide such a cavity, allowing electromagnetic radiation to pass into and out of the device cavity. However, a hermetic seal around a glass cavity typically uses a glass frit adhesive, which may require processing temperatures in excess of 400C to melt and fuse the frit. These temperatures may exceed the temperatures that can be withstood by many of the thin metal layers used to create the optical device. Thus, encapsulation of an optical device in a transparent device cavity which is hermetically sealed has been an elusive goal.
It is possible to bond an optically opaque substrate, such as silicon, to an optically transparent substrate such as glass, with the glass substrate forming a lid over the silicon wafer and microfabricated device. Anodic bonding of a silicon substrate to an optically transparent glass substrate is known, wherein voltage and heat are applied between the glass wafer and the silicon wafer. The voltage applied promotes the growth of the oxide layer between the silicon and the glass, which bonds the substrate materials together.

Method and device using silicon substrate to glass substrate anodic bonding


The present invention discloses a self-fastening cage of a magnetic resonance device (MRD) for providing a homogeneous, stable and uniform magnetic field therein, characterized by an outside shell comprising at least three flexi-jointed superimposed walls. The multi-streamed MRD comprising a cage including a closed magnetic circuit constructed from strong permanent magnets; and optionally a shimming mechanism selected from an array of active shim coils, passive shimming elements; a contained cavity within which the magnetic field strength is approximately uniform; and a plurality of conveyor belts, pipes or any transportation means by which a plurality of samples are introduced into the region of uniform magnetic field; such that magnetic resonance measurements are made on a plurality of samples within the region of uniform magnetic field. The invention depicts a cost effective method for obtaining a self-fastening cage.

Electromagnetic based instruments for measuring properties of matter or identifying its composition are well known. Magnetic resonance spectroscopy is one of the principal measuring techniques used to obtain physical, chemical and structural information about a molecule. In order to be able to perform magnetic resonance spectroscopy with high resolution capabilities providing a high quality image (i.e., resolution and contrast) the magnetic field used must be extremely stable and uniform.
However in order to achieve such uniformity, elements correcting the inhomogeneousness of the main magnetic field are added, according to the principle of fields' superposition. Coils, magnetic parts, or all other means enabling correction of the imperfections of the principal field are added in order to obtain a homogeneous total field in the zone of interest.
U.S. Pat. No. 5,959,454 to Westphal et al. discloses a magnet arrangement for an NMR tomography system, in particular for skin and surface examinations, which contains a one sided NMR system having two ring magnets and a cylindrical magnet. Their respective locations provide a certain degree of uniformity.
U.S. Pat. No. 6,191,584 presents a permanent magnet for NMR image detection which contains a magnetic structure having a yoke and magnetic poles, so shaped as to delimit or enclose a cavity.
In order to achieve a uniform and strong magnetic field using permanent magnet material, the use of simple permanent magnet structures, like C-magnet or H-magnet, is not suitable. Therefore, much more complex assemblies are needed in order to achieve the required magnetic field. Modern magnetic material today can hold high magnetic energy, and if a magnetic circuit is designed correctly, uniformity and field strength can be achieved and controlled with high efficiency. A cost-effective self-fastening cage useful for providing a homogeneous, stable and uniform magnetic field, thus still meets a long felt need.

Self-fastening cage surrounding a magnetic resonance device and methods thereof


An auto-contactor system and method are provided for optimizing the size and placement of contact elements for connecting signal lines from one layer of an integrated circuit to another layer of the integrated circuit. The auto-contactor system includes a contact area mechanism and an optimizing mechanism. The contact area mechanism identifies a contact area that overlaps the signal line from the first layer of the integrated circuit and the signal line on the second layer of the integrated circuit. The optimizing mechanism calculates an optimal size of a plurality of contacts in the contact area. The auto-contactor system also provides for and can be thought of as a method that optimizes the placement and size of contact elements for connecting signal lines on a first layer of the integrated circuit to signal lines on a second layer of the integrated circuit that comprises the following steps: (1) identifying a contact area that overlaps the signal lines from the first layer of the integrated circuit and the second layer of the integrated circuit; and (2) calculating an optimal size of a plurality of contacts in the contact area.

1. Field of the Invention
This invention generally relates to the placement of contacts for signal lines between layers on an integrated circuit, and more particularly, to an auto-contactor system and method for automatically placing variable size contacts (a.k.a. xe2x80x9cviasxe2x80x9d) between same named signals on different layers of an integrated circuit chip automatically.
2. Discussion of the Related Art
Integrated circuits (IC) are electrical circuits comprised of transistors, resistors, capacitors, and other components on a single semiconductor xe2x80x9cchipxe2x80x9d. These components are interconnected to perform a given function such as a microprocessor, programmable logic device (PLD), electrically erasable programmable memory (EEPROM), random access memory (RAM), operational amplifier, or voltage regulator. Very large scale integration (VLSI) technology is often utilized to create semiconductor integrated circuits comprising thousands of logic elements and signal lines. VLSI circuits are fabricated on silicon, gallium-arsenide or germanium wafer (i.e., substrate) and typically include signal lines and logic structures.
The logic element structures control the signal processing and comprise irregular elements, such as gates, latches, memory arrays or multipliers. These logic structures are built up on an integrated circuit into multiple layers. In order for each of these logic elements to perform they need inputs and outputs. These inputs and outputs are usually signal lines from other logic elements. These signal lines typically run horizontally on a layer or vertically through a layer. The signal lines that run horizontally in a layer also are typically run orthogonally on one side of the layer as compared to the opposite side of the layer. For example, this means that in adjacent pair of layers the upper layer the signal lines run in one direction, such as in north-south, and then on the lower layer the signal lines would be perpendicular and run east-west. The conductors carry control signals, data signals, clock signals, power (such as VDD) and ground. A hole is created in the insulating material between layers to get these power, ground and signal lines from one layer or another. A contact is then placed in the hole so as to connect conductors on adjacent layers. This allows VDD, ground and data signals to be routed wherever needed on a chip.
The lines for VDD and ground are typically wide lines to reduce resistance. However, the contacts between layers are generally of fixed size. These contacts have a high resistance compared to the conductive lines. That being the case, one typically places multiple fixed size contacts to connect conductors between adjacent layers. It is desirable to have numerous contacts for these power lines in order to minimize resistance.
In general, with regard to generating the design of the VLSI circuits, net lists are generated by various means including extraction from schematics and xe2x80x9cartworkxe2x80x9d (detailed layouts of components and connecting conductors and contacts). The net list is a listing of all the logic elements and the connectivity of the logic elements that comprise a block of logic. The net list is fed into a placement and routing tool, which generates the layout of the VLSI circuits therefrom. The resulting layout designates the actual position and wiring of each logic element of the VLSI circuits. The degree to which the placement of each component is optimized is a function of the design criteria of the placement and routing algorithm implemented by the placement and routing tool and the amount of central processing unit (CPU) time devoted to the operation of the placement and routing tool.
These algorithms are designed to minimize the routing resistance and capacitance in the VLSI circuits by minimizing the routing lengths between connections. If the routing lengths are minimized, then the routing capacitive load is minimized, and the VLSI circuits is faster, smaller (i.e., denser), and consumes less power, all of which are desirable attributes. Most conventional placement and routing algorithms achieve this optimization via an iterative, pseudo-random placement scheme. After an initial placement of the components, each component is considered for a move to see if the design can be better optimized by the move. The type of moves considered are usually either (1) swapping the position of a component with another randomly selected component, or (2) moving the position of a component to a randomly selected new location. The determination of whether or not the design can be optimized by the move is based upon a cost function. For example, the cost function may be the total wire length of the design, whereby the lower the total wire length, the more optimized the design.
A calculation is done by the algorithm for each move to determine the change in the cost function caused by the proposed move. If the change is negative, thereby generating a new lower cost function, then the move is accepted and used as a new placement for the component under consideration for further iterations of the algorithm. Selecting only negative cost function changes is called a xe2x80x9cgreedyxe2x80x9d algorithm.
A more advanced placement and routing algorithm, referred to as xe2x80x9csimulated annealingxe2x80x9d, will occasionally accept moves producing a positive change in the cost function. In such cases, the simulated annealing algorithm will either accept or refuse the proposed move based upon the magnitude of a positive change, a decreasing value called the xe2x80x9ctemperaturexe2x80x9d, and a random number so that the selection of the move is a probabilistic selection. Thus, a simulated annealing placement and routing algorithm performs design optimization via multiple iterations of a pseudo-random placement scheme modified by a temperature cost function.
While the methods described above and those known in the industry are adequate when placing standard logic elements, such as gates and latches, in the VLSI circuits, they have proven to be inadequate when placing and routing contact elements for wide signal lines between the layers of the IC chip. Simply stated, the current methods known in the industry do not automatically generate contacts between same name signals on different layers of an integrated circuit in an efficient manner. The current methods known in the industry do not adjust the contact density according to the size and shape of the individual areas where contacts from one signal line on one integrated circuit layer can be placed to be in contact with a same name signal line on a different layer while still providing good conductivity between the layers and avoiding the generation of excessive number of contacts which could overwhelm programs which subsequently process the layout data (e.g., DRC, mask generator).
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.
To achieve the advantages and novel features, the auto-contactor provides a system and method for optimizing the size and placement of contact elements for connecting signal lines from one layer to another. Briefly described, in architecture, the auto-contactor can be implemented as follows. The contact area mechanism identifies a contact area that overlaps the signal line from the first layer of the integrated circuit and the signal line on the second layer of the integrated circuit. The optimizing mechanism calculates an optimal size of a plurality of contacts in the contact area.
The auto-contactor system of the present invention also provides for and can be thought of as a method that optimizes the placement and size of contact elements for connecting a signal line on a first layer of the integrated circuit to a signal line on a second layer of the integrated circuit that comprises the following steps: (1) identifying a contact area that overlaps the signal line from the first layer of the integrated circuit and the second layer of the integrated circuit; and (2) calculating an optimal size of a plurality of contacts in the contact area.
In accordance with another aspect of the auto-contactor system, a computer readable medium is provided having program code for controlling a computer system for generating a design that optimizes the placement and routing of contact elements for connecting wide signal lines for one layer to another. In this implementation, the computer readable medium includes a first code segment configured to identify a contact area that overlaps the signal lines from the first layer of the integrated circuit and the second layer of the integrated circuit; and second code segment configured to calculate an optimal size of a plurality of contacts in the contact area.
Other features and advantages of the auto-contactor system will become apparent to one with ordinary skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the appended claims.

Auto-contactor system and method for generating variable size contacts


A MOS transistor that includes: a semiconductor substrate; a well region formed in the semiconductor substrate, where a trench region is defined in the well region; an isolator formed on a corner of the trench region, where the trench region is filled with polysilicon; a gate conductor formed over the trench region; and source/drain regions formed within the well region laterally aligned to the gate conductor. A suitable method to form the MOS transistor includes the acts of: forming a well region in a semiconductor substrate; forming a trench region in the well region; forming an isolator in a corner of the trench region; filling the trench region with polysilicon; forming a gate conductor formed over the trench region; and forming source/drain regions within the well region on opposite sides of the gate conductor.

1. Field of the Invention
The present invention relates to a process for fabricating semiconductor devices, and more particularly, to a MOS transistor and a method for fabricating the same.
2. Description of the Related Art
FIG. 1 shows a conventional MOS transistor. The conventional MOS transistor includes a P or N-type semiconductor substrate 1, a well region 3 formed in the semiconductor substrate 1 doped with impurities having conductivity opposite to those doped in the substrate 1, and isolation regions 2 realized by forming openings in the semiconductor substrate 1 and filling the openings with an oxide material (e.g. silicon oxide).
Formed over a xe2x80x9cchannel portionxe2x80x9d of the well region 3 are a gate oxide layer 4 and a polysilicon gate structure 5 (hereinafter xe2x80x9cgate conductorxe2x80x9d refers to both gate oxide layer 4 and a polysilicon gate structure 5 together). Oxide spacers 7 are formed along sidewalls of the gate oxide layer 4 and the gate structure 5. Formed in the well region 3 between the gate structure 5 and the isolation regions 2 are source/drain region 6 into which impurities having a conductivity opposite to that of the impurities doped into the well region 3, are shallowly doped.
Where a channel length, i.e., the spacing between the source and drain regions (item C of FIG. 1) of the above described MOS transistor is less than 2 xcexcm, xe2x80x9cshort channel effectsxe2x80x9d such as punchthrough can occur. Punchthrough is associated with the merging of source and drain depletion layers, i.e., when the drain depletion layer extends across the substrate and reaches the source depletion layer, thereby causing a destructive conduction path or leakage current between the source and drain. A drain depletion layer forms and spreads as the voltage applied across the transistor from the drain to the source (hereinafter drain-source voltage VDS) is increased. At a certain drain-source voltage VDS called the punchthrough voltage, the width of the drain depletion layer approaches the channel length, and the depletion regions meet, resulting in punchthrough. Punchthrough results in, e.g., a constant drain current for increasing drain voltages.
Therefore, what is needed is a method and apparatus for controlling punchthrough in semiconductor devices.
An embodiment of the present invention includes a MOS transistor that includes: a semiconductor substrate; a well region formed in the semiconductor substrate, where a trench region is defined in the well region; an isolator formed on a corner of the trench region, where the trench region is filled with polysilicon; a gate conductor formed over the trench region; and source/drain regions formed within the well region laterally aligned to the gate conductor.
An embodiment of the present invention includes a method of forming a MOS transistor, including the acts of: forming a well region in a semiconductor substrate; forming a trench region in the well region; forming an isolator in a corner of the trench region; filling the trench region with polysilicon; forming a gate conductor formed over the trench region; and forming source/drain regions within the well region on opposite sides of the gate conductor.
Various embodiments of the present invention will be more fully understood in light of the following detailed description taken together with the accompanying drawings.

MOS transistor that inhibits punchthrough


A versatile device that enables at least one receptacle to be installed in a raceway system. The versatile device includes a hanging box and a faceplate adapter. The hanging box is secured to the raceway system and the faceplate adapter is positioned over the hanging box and secured to the raceway system. The hanging box has a compartment that houses at least one receptacle and a removable divider wall that is positioned within the compartment. The faceplate adapter has a main body with an aperture for providing access to the hanging box. The main body of the faceplate adapter also has a removable section that is positioned within the aperture such that removal of the removable section expands the aperture.

Multi-channel wiring raceway systems are common for installation of power and communication devices within the same duct. These raceway systems are usually used in an office, commercial or industrial setting where design, layout, production and seating arrangements can be changed or upgraded. If the system requires a change or modification, such as moving or installing a power or communication outlet, the system must be reconfigured. Typically, an offset power or communication box may be added to the raceway system to accommodate the modification. However, there may not be available space to position an offset box adjacent to the raceway system or it may not be cost effective to add offset boxes to accommodate the system modifications.
As such, it is desirable to provide a device that creates a versatile raceway system in which the number and location of the power and communication outlets can be easily varied throughout the system.


A filter device, in particular for fluids polluted with admixtures of water, such as diesel oil, includes a filter housing (1) having a fluid inlet (43), a fluid outlet (44) and a filter element (9). During the filtering process, the fluid can flow through the filter medium (11) of the filter element from the unfiltered side (14) to the filtered side (13) of the filter medium and into its inner filter cavity (17). On at least one side of the filter medium (11), a water-separating system (23) has a separating region (25) for separated water. The water separating system is connected via at least one water opening (35) that is open toward the separating region (25) to a water collecting chamber (45). The filter element (9) has a passage (29) forming a fluid connection to the inner filter cavity (17) and can be connected to an element receptacle (47) of the filter housing (1). A fluid-conveying system (41) forms fluid paths separated from each other. The first fluid path (59/69) leads from the fluid inlet (43) of the housing (1) to the unfiltered side (14) of the filter element (9). The second fluid path (57) connects the respective water opening (35) to the water collecting chamber (45).

Filter devices of the aforementioned type are known from the prior art. Such filter devices are typically used in fuel systems for internal combustion engines to protect sensitive components, in particular the injection systems, against degradation due to the water content entrained in the fuel. In this case, separation of the water content entrained in the fuel can be effected by a coagulation process during which water droplets are formed on the filter medium. These water droplets can flow out of the separation space, formed in the filter element, to the water collecting space.
To ensure the operational reliability of the systems located downstream of the filter, avoiding system contamination by dirt is critical in the processes of changing the filter element as necessary over the service life. The fluid connection between the filtered side of the filter element and the fluid outlet of the housing is interrupted when the end cap of the used filter element is decoupled from the element retainer. Dirt that has accumulated on the used filter element must be prevented from falling off. A separate reliable conveyance of the fluid by the water that forms is also desirable to increase operational reliability.

Filter device and filter element provided therefor