A memory embedded semiconductor device according to the present invention has a memory region having a memory transistor and a logic region having a logic transistor each provided in a common semiconductor substrate. The logic transistor has a gate electrode provided on the semiconductor substrate and source/drain diffusion layers formed in the semiconductor substrate each having a silicide film formed thereon. On the other hand, the memory transistor has a gate electrode provided on the semiconductor substrate and source/drain diffusion layers formed in the semiconductor substrate each having a silicide film formed thereon to be thinner than the silicide film formed on each of the source/drain diffusion layers of the logic transistor.

The present invention relates to a memory embedded semiconductor device comprising a memory such as a DRAM or a ROM and a high-speed CMOS logic circuit.
A DRAM embedded LSI is an LSI having a memory region and a logic region each provided in a common substrate and suitable for processing a large amount of data at a high speed due to the structural feature thereof which allows a wider data bus to be provided between the memory and logic regions. In addition, the DRAM embedded LSI need not use wiring provided on a printed circuit board or the like which is located outside of the LSI package. This achieves a reduction in the power consumption of a system and renders the DRAM embedded LSI extremely effective as a system LSI.
To enhance the performance of a transistor (logic transistor) in the logic region of the DRAM embedded LSI, it is necessary to reduce the parasitic resistance of the transistor by using a salicide technology. However, since a shallow junction is used in each of the source/drain regions of a transistor (memory transistor) provided in the memory region with the view to suppressing a short channel effect, a leakage current to the substrate increases when a silicide layer is formed on each of the source/drain regions of the memory transistor so that a charge retention time (pause time) is shortened. A description will be given herein below to the structures of conventional DRAM embedded LSIs and fabrication methods therefor with reference to the drawings.
CONVENTIONAL EMBODIMENT 1
FIG. 3 shows a cross-sectional structure of a memory embedded semiconductor device (DRAM embedded LSI) according to a first conventional embodiment disclosed in Japanese Laid-Open Patent Publication No. 2000-332220 (Abstract).
As shown in the drawing, a memory embedded semiconductor device according to the first conventional embodiment has a logic region Rlogc comprising logic transistors and a DRAM region Rdram comprising the transistors of DRAM memory cells (memory transistors) disposed in a common semiconductor substrate 100. Although the logic transistors include a p-channel transistor and an n-channel transistor, the drawing shows only the n-channel transistor. The drawing also shows the structure in which n-channel transistors are used as the memory transistors.
The logic transistor comprises: a gate insulating film 102 and a gate electrode 103 each provided on an active region surrounded by isolations (trench isolations) 101; source/drain diffusion layers 104 formed in the regions of the semiconductor substrate 100 located sidewise of the gate electrode 103; and sidewalls 105 covering the side surfaces of the gate electrode 103. The gate electrode 103 is composed of a lower electrode 103a made of polysilicon containing an n-type impurity and an upper electrode 103b made of silicide. The upper electrode 103b is formed simultaneously with source/drain silicide layers 106 formed on the source/drain diffusion layers 104 by a common salicide process step.
Each of the memory transistors comprises: a gate insulating film 112 and a gate electrode 113 each provided on an active region surrounded by the isolations (trench isolations) 101; source/drain diffusion layers 114 formed in the regions of the semiconductor substrate 100 located sidewise of the gate electrode 113; and sidewalls 115 covering the side surfaces of the gate electrode 113. The gate electrode 113 is composed of a lower electrode 113a made of polysilicon containing an n-type impurity and an upper electrode 113b made of silicide. It is to be noted that source/drain suicide layers are not provided in the memory transistor.
CONVENTIONAL EMBODIMENT 2
FIG. 4 shows a cross-sectional structure of a memory embedded semiconductor device according to a second conventional embodiment disclosed in Japanese Laid-Open Patent Publication No. 2001-127270 (Abstract), which allows the higher-speed operation of the memory transistors.
As shown in the drawing, the memory embedded semiconductor device according to the second conventional embodiment has a logic region Rlogc and a DRAM region Rdram disposed in a common semiconductor substrate 200 in the same manner as in the first conventional embodiment.
A logic transistor comprises: a gate insulating film 202 and a gate electrode 203 each provided on an active region surrounded by isolations (trench isolations) 201; source/drain diffusion layers 204 formed in the regions of the semiconductor substrate 200 located sidewise of the gate electrode 203; and sidewalls 205 covering the side surfaces of the gate electrode 203. The gate electrode 203 is composed of a lower electrode 203a made of polysilicon containing an n-type impurity and an upper electrode 203b made of silicide. The upper electrode 203b is formed simultaneously with source/drain silicide layers 206 formed on the source/drain diffusion layers 204 by a common salicide process step.
On the other hand, a memory transistor comprises: a gate insulating film 212 and a gate electrode 213 each provided on an active region surrounded by the isolations (trench isolations) 201, source/drain diffusion layers 214 formed in the regions of the semiconductor substrate 200 located sidewise of the gate electrode 213; and sidewalls 215 covering the side surfaces of the gate electrode 213. The gate electrode 213 is composed of a lower electrode 213a made of polysilicon containing an n-type impurity and an upper electrode 213b made of silicide. The upper electrode 213b is formed simultaneously with source/drain silicide layers 216 formed on the source/drain diffusion layers 214 by a common salicide process step.
In the memory embedded semiconductor device according to the first conventional embodiment, a junction leakage can be reduced and an impurity concentration in each of the source/drain diffusion layers 114 can be reduced because the silicide layer is not formed on either of the source/drain diffusion layers 114 of the memory transistor. This provides a memory transistor with an excellent short-channel effect (with a reduced off leakage). As a result, it becomes possible to implant a logic transistor operable at a high speed, while suppressing a reduction in pause time.
In recent years, however, an ultra-high-speed operation at about 200 MHz has been requested of a memory as a replacement of an SRAM in the DRAM embedded LSI. In the memory embedded semiconductor device (DRAM embedded LSI) according to the first conventional embodiment, the problem is encountered that it is difficult to allow a high-speed operation because of the high parasitic resistance of each of the source/drain diffusion layers of the memory transistor.
By contrast, the silicide layer 216 is formed on each of the source/drain diffusion layers 214 of the memory transistor in the memory embedded semiconductor device according to the second conventional embodiment. The arrangement has achieved an impurity concentration equal to that in the logic transistor in each of the source/drain diffusion layers 214. A resulting reduction in parasitic resistance due to the silicide allows the higher-speed operation of the memory transistor and thereby implements a high-speed memory operation.
In the memory embedded semiconductor device according to the second conventional embodiment, however, the memory transistor is allowed to have only a leakage characteristic as low as that of the logic transistor so that the pause time is shortened, though the memory operation is performed. Accordingly, it becomes necessary to increase the number of times data refreshing is performed so that power consumption is increased. As a result, the problem is encountered that it is difficult to embed a DRAM having a memory capacity over 10 Mbits in terms of power consumption, though the embedding of a DRAM having a memory capacity of about 1 to 2 Mbits presents no serious problem.

Memory embedded semiconductor device and method for fabricating the same


The glass bottle inspection method and apparatus performs successively producing differential images from original images successively captured from the glass bottle to be inspected while the glass bottle is being rotated about its own axis, comparing the differential images with the template to judge whether the glass bottle is defect-free or not, and combining all the differential images obtained from the glass bottle to be inspected in one inspection cycle to produce a differential composite image, using the differential composite image as a provisional template when all the differential images obtained from the glass bottle in one inspection cycle are judged as representing a defect-free glass bottle, and correcting the template using the provisional template.

In producing a glass bottle, a crack such as crazing may be sometimes formed in a wall thickness of a bottle-mouth portion. This crack is referred to as a check. Glass bottles tend to have checks in limited regions of the bottle-mouth portions. Typically, there are a check generated in the top surface or near the top surface of the bottle mouth, a check generated in a screw thread portion of the bottle mouth, and a check generated in a skirt portion of the bottle mouth. Further, depending on the direction of the crack, the checks are classified into a vertical check extending in a vertical direction (substantially vertical direction) and a lateral check extending in a lateral direction (substantially horizontal direction).
Because the above-mentioned check can cause damage to the glass bottle, the presence or absence of a check is detected by imaging the bottle-mouth portion, and the glass bottle having the check is removed as a defective bottle.
Heretofore, there has been known a glass bottle inspection apparatus for automatically inspecting a glass bottle by imaging a bottle-mouth portion of a glass bottle to detect whether there is a check or not. The known glass bottle inspection apparatus has a single illuminating unit disposed above a bottle-mouth portion of a glass bottle and a number of (e.g., seven) cameras disposed around the bottle-mouth portion so as to surround the bottle-mouth portion. Scattered light emitted from the illuminating unit is applied to the bottle-mouth portion of the glass bottle, and if there is a check, the light is reflected by a crack plane of the check and is thus illuminated brightly. Therefore, images captured by the cameras include a brighter image area corresponding to the check than other image areas.

Glass bottle inspection method and apparatus


The invention relates to a method and a system for establishing communication relations (stream1, stream2, stream3) via a communication medium, at least one communication relation (stream1, stream2) being established via said communication medium. According to the invention, information on queries for establishing one respective communication relation (stream1, stream2, stream3) is recorded, and, depending on the recorded information, at least one of the already established communication relations (stream1, stream2) is terminated or maintained. The information recorded can be e.g. the query times (ti), the interval lapsed between two queries being used to infer the type of communication relation (stream1, stream2, stream3). According to the invention it is for example possible for short intervals to infer queries for IP-TV data streams and previously established communication relations (stream1, stream2) are directly terminated in order to save band width.

In current communication networks, the users require increasingly higher data transmission rates. Transmission methods which can provide high transmission rates also in the subscriber access networks of a communication network are, for example, methods which operate in accordance with the xDSL method. Using these transmission methods, the operators of communication networks can also offer their customers broadband connections, for example to the Internet, by means of which the subscribers can utilize numerous applications in an increasingly simpler and more rapid manner. An example of such a data-intensive application for which high transmission rates are needed is, for instance, the transmission of real-time-related multimedia files.
In particular, for example, popular television channels will also in future be increasingly transmitted via packet-oriented communication networks such as, for example, an IP (Internet Protocol) network. This service is considered to be part of the so-called "triple plays", which means that three—originally separate—data services (telephone, Internet, television) are conveyed via the same communication network.
In this context, the information is usually transmitted in so-called streams in the case of television transmissions via an IP network (IP TV). This means that a central server converts the television channels into a continuous flow of data (the channels are "streamed") and these data streams are distributed to individual subscribers. As part of such a distribution service, the data stream is received by the individual subscribers, converted back and subsequently displayed on a screen.
To be able to successfully offer this type of television transmission, however, it is necessary to observe that the subscribers or the customers are also provided with at least the same quality of television pictures as is the case with current TV networks (cable, satellite, aerial) with such a streaming method.
This specifically means that, on the one hand, adequate picture quality is achieved, for example. Especially in the case of video transmissions, transmission errors become apparent in errors in the picture representation which are easily recognized and therefore extremely disturbing. Thus, for example, the picture may appear blurred or so-called block errors occur, i.e. individual parts or blocks of the picture are represented wrongly.
On the other hand, however, to successfully offer IP TV, it must also be ensured that further features or characteristics to which the subscribers to conventional television transmission networks are used are also offered in the case of IP TV. One of these characteristics is a shortest possible switch-over time when switching between two television channels.
While this is normal with conventional TV networks since all receivable channels are simultaneously present at the connection of the subscriber in these networks, it is different in the case of IP-based (or Ethernet) networks: in such networks, only the requested channels are ever present at the connection of a subscriber. In principle, a subscriber in an IP network informs a central server that he wishes to receive a certain stream (a certain television channel), i.e. the subscriber makes a request for a communication connection with this server. The server thereupon forwards the corresponding stream to the subscriber. In the case of a switch-over process, which corresponds to a change of the stream, this switch-over must therefore first be notified to the server by means of various protocols and finally be carried out by the server (or by two servers, if both streams come from different servers). With each switch-over of the television channel, a new stream must thus be requested and set up (or a new communication connection established), a method which is more elaborate and therefore needs more time than the switch-over in conventional TV networks.
In current IP networks, the distributing of a stream to one or more subscribers is achieved by means of so-called multipoint connections. In this context, a data stream can be conveyed from a starting point or transmitter (for example a central server within the IP network) simultaneously to several receivers or subscribers. This is a "point-to-multipoint" connection or a so-called "multicast" method or multicast transmission.
Multicast transmissions are currently controlled in most cases by means of the "Internet Group Management Protocol" (IGMP). The IGMP is based on the Internet Protocol and provides for group communication. In a multicast transmission (multicasting), single IP packets are simultaneously distributed under an IP address to several stations (to a group of stations). To reduce the volume of data produced, if possible, the IGMP provides the possibility of distributing groups dynamically. Individual subscribers or connections are thus allocated to certain groups with a particular offer. However, these groups are not administered in the transmitting station but, for example, in individual network nodes or in the routers along the way to the receiver. For this purpose, information about the outgoing interface at which a station or a connection is located to which certain multicast IP packets are to be forwarded is stored in the routers. In the IGMP, functions are implemented by means of which, for example, the routers can communicate with one another and by means of which stations can inform a router that the corresponding subscriber wishes to receive certain multicast IP packets.
In multipoint connections managed in this manner, it is thus in most cases not known in the transmitter which or even how many subscribers receive its IP packets. According to IGMP, the transmitter only sends out a single data packet to the corresponding higher-level router. It is only within the individual routers of the communication network that the IP packets are finally multiplied if necessary. This is done in dependence on the number of stations connected to the respective routers which are intended to receive the corresponding IP packets. Thus, all network nodes involved in the communication must support a multicast protocol such as IGMP.
In multicast protocols, commands for requesting IP packets also exist in addition to numerous other protocol commands: for example, a subscriber applies for membership in a group by means of the so-called "join" command ("JoinGroup"), i.e. the subscriber may request a certain stream or television channel whereupon he becomes a further receiver of the corresponding IP packets.
If a subscriber wishes to leave a group of which he is currently a member, this can be done in accordance with various methods according to the prior art. On the one hand, this can be done under timer control (e.g. IGMP Version 1), on the other hand, a membership can also be terminated directly by means of a suitable command (e.g. IGMP, Version 2). In the case of timer-controlled methods (like the IGMPv1 in which there is no terminating command), according to the protocol a subscriber device sends to the corresponding higher-level node, at predetermined time intervals, information which indicates that the respective subscriber still wishes to remain a member of said group. In the case where no such information is received at the network node within the predetermined time interval (when the timer in the network node has expired), the connection is terminated by the network node.
In other multicast protocols, there are certain commands for deliberately terminating a membership (e.g. IGMPv2: "LeaveGroup") Although the possibility thus exists in such cases to deliberately leave certain groups, numerous current multicast implementations such as, among others, for instance current set top boxes, still continue to operate without this "leave" command. In such cases, too, leaving a group is then controlled by timer.
A further possibility for ending membership of a group is the so-called "fast leave". This is an implicit ending of membership. This means that with each respective new "join" request by a subscriber, that is to say whenever the subscriber, for example, applies for a new television channel, the previous membership of another group is automatically ended. However, this method can only be used in rare cases since a prerequisite for this is that the subscriber in each case only has or wishes to have a single data stream.
Management of the individual subscribers and their group membership, that is to say management of the multicast connections can also be carried out, for example, centrally. Information regarding which connected subscribers have subscribed to which IP data streams or belong to which groups can thus be stored, e.g. in a central management unit or also in the DSLAM itself. For this purpose, for example, a table can be set up in which the currently subscribed IP streams are stored for each subscriber connection or else for each "media access control" address (MAC address), i.e., even in the case where several terminals are connected to one subscriber line, the group membership of each individual terminal is logged by means of the MAC address which is unambiguous for each device connected to an Ethernet. The information about the group membership can be recorded directly in the DSLAM, for example by monitoring the IGMP ("IGMP snooping").
In most cases, the following disadvantage is produced when leaving a group, or when subscribing to a new group, particularly in the abovementioned IP TV applications: if a subscriber subscribes to a new group, groups previously subscribed to are not always automatically left. This leads to the new applications in most cases not being able to immediately access the required bandwidth since a part of the existing bandwidth is still reserved for the previous application no longer required. Especially in the case of, for example, IP TV, this leads to an extension of the abovementioned problem of longer switch-over times since the newly selected channel cannot be displayed unless the transmission resources required for displaying the previous channel have first been released again.

Method and system for establishing communication relations


A seat belt buckle guard comprises a one-piece, molded plastic, box-like enclosure having one open end and an opposite end wall with a slot. The seat belt buckle fits through the open end into the enclosure with its latch plate receiving slot aligned with the slot in the housing. The latch plate on one belt half can be inserted through the housing slot to make with the buckle. Formed in the top wall and the end wall is an opening for gaining access to the buckle release button. In one arrangement, the opening is a narrow slot through which a flat object, such as a key, can be inserted to operate the buckle's release button. In accordance with an alternative embodiment, the opening is a circular aperture of a size permitting one's finger to be inserted to operate the release button. The opening is surrounded by a tubular stub or neck threaded on its exterior to receive a child-resistant safety cap of the type commonly used on medicine bottles. When the cap is removed, a finger can be inserted to activate a release button or the unit can be separated by folding along the hinge to allow actuation of a lever-type release or to gain access to a release button disposed on a front end edge of the buckle receptacle.

I. Field of the Invention
This invention relates generally to seat belts of the type used in motor vehicles and aircraft, and more particularly to a device to be used with such seat belts for preventing the uncoupling or release thereof by small children and/or the unintended or inadvertent release of seat belts by adults.
II. Discussion of the Prior Art
Almost all states now require passenger automobiles, school buses and perhaps other vehicles to be equipped with passenger seat belts for restraining the occupants of such vehicles in the event of accidents. Similarly, all aircraft includes seat belts to prevent sudden turbulence or the like from throwing the passenger from his/her seat. Seat belts of the type concerned here generally comprise a pair of nylon webs or straps which are anchored at one end to the frame of the vehicle. The other end of one of the straps has a seat belt buckle having a release button or release lever mounted thereon and a female slot for receiving a latch plate secured to the free end of the other strap. A latching mechanism is incorporated within the buckle for locking the latch plate within the buckle, the release button, when depressed, or the release lever, when lifted, allowing the two parts to be separated.
It has been found that when young children are restrained in a vehicle seat by means of a seat belt of the type described, at a relatively young age, they are able to master the operation of the release button/lever and can often do so without the knowledge of the adult driver. This can be extremely dangerous in the event of an accident.
It can also happen that an adult may inadvertently or unwittingly depress the buckle release button, allowing the belt halves to uncouple.
It is therefore a principal object of my invention to provide an improved guard mechanism for preventing small children from releasing their vehicle seat belt and for inhibiting any unintended release of the seat belt by older persons. We are not the first to address this particular problem. The patent art describes various types of seat belt buckle guards for performing the same function. For example, the Boriskie Pat. No. 4,731,912 describes a seat belt buckle guard in the form of a box-like device having first and second housing portions which are hinged together allowing the seat belt buckle with the release mechanism thereon to be inserted into a first box-like housing and then have the second part of the housing snapped closed about the buckle. The top of the second box is sufficiently rigid that it cannot be depressed to the point where the release button of the seat belt can be actuated. Small children can soon master the act of opening the hinged cover of the box and can then depress the buckle release button.
The Reed Pat. No. 4,939,824 describes yet another vehicle safety belt buckle cover in the form of a generally rectangular shaped covering member which substantially overlays the surface of the buckle and its release button. The cover is held closed relative to the buckle by means of a strap. This design also suffers from the defect that in only a short time, a child can readily effectively remove the buckle guard to gain access to the buckle's release mechanism.
Still other patents describing seat belt buckle guards are Portuese 5,052,087, Haffey 4,987,662, Smith 4,961,251 and Gullickson 4,675,954.


A polypropylene resin composition which is excellent in transparency and which shows very low pH reduction of the extract obtained in a promoted hot water-extraction test of a polypropylene resin which has been irradiated with radiant rays for sterilization. The polypropylene resin composition comprises 100 parts by weight of a polypropylene resin, 0.01 to 1.0 part by weight of a metal diarylphosphate represented by the following general formula (I): ##STR1## (wherein R.sub.1 and R.sub.2 each represents a hydrogen atom or an alkyl group; M represents an alkali metal or an alkaline earth metal; n is an integer of 1 or 2; and A represents an alkylidene group); and 0,001 to 1.0 part by weight of a hydroxide of an alkali metal, an alkaline earth metal or an element of the aluminum group. The polypropylene resin composition is suitable for use in making medical instruments, containers for foods or the like.

1. Field of the Invention
The present invention relates to a polypropylene resin composition which is excellent in transparency and which shows very low pH reduction of an extract in a promoted hot water-extraction test of the polypropylene resin which has been irradiated with radiant rays for sterilization.
2. Description of the Related Art
Polypropylene resins are excellent in mechanical properties, heat resistance and resistance to chemicals as well as sanitary properties and hence have been widely used in various fields, for instance, containers for foods such as tablewares, containers for frozen desserts, trays, containers for fast-foods and containers for margarine; and medical instruments such as syringes of injectors, spitz tubes, containers for transfusion and cylinders.
However, it is important in the applications of the resins as containers for foods and medical instruments to permit the confirmation on whether the contents of a container are contaminated with dust or other foreign matter or not and it is not desirable that the color tone peculiar to the contents be changed when they are charged in a container.
For this reason, the use of polypropylene resin excellent in transparency has been needed in these applications.
There have widely been adopted a method in which a nucleating agent for crystallization is added as a means for improving the transparency of the polypropylene resins and, in general, a sorbitol derivative or a metal diarylphosphate is added as such a nucleating agent.
Among these sorbitol derivatives, those effective for improving the transparency of the polypropylene resins are, for instance, 1.multidot.3,2.multidot.4-dibenzylidene sorbitol, 1.multidot.3,2.multidot.4-di-(methylbenzylidene)sorbitol and 1.multidot.3,2.multidot.4-di-(ethylbenzylidene)sorbitol. Polypropylene resin compositions to which 1.multidot.3,2.multidot.4-di-(methylbenzylidene)sorbitol or 1.multidot.3,2.multidot.4-di-(ethylbenzylidene)sorbitol is added are excellent in transparency, but the sorbitol derivative is dissolved or dissipated in hot water when the resin compositions are immersed therein and floating matter is generated in the extract after it is cooled. This causes a safety and hygiene concerns.
On the other hand, the polypropylene resin composition to which 1.multidot.3,2.multidot.4-dibenzylidene sorbitol is added does not cause severe formation of floating matter in the extract obtained after immersing it in hot water when the resulting extract is cooled, but the transparency thereof is still insufficient.
Among metal diarylphosphates, those effective for improving the transparency of the polypropylene resins are, for instance, sodium 2,2'-methylenebis(4,6-di-t-butylphenyl) phosphate, lithium 2,2'-methylenebis(4,6-di-t-butylphenyl) phosphate, calcium di-(2,2'-methylenebis(4,6-di-t-butylphenyl)phosphate], sodium 2,2'-methylenebis(4-methyl-6-t-butylphenyl)phosphate and sodium 2,2'-methylenebis(4-ethyl-6-t-butylphenyl)phosphate.
The polypropylene resin composition to which these metal diarylphosphates are added does not cause the formation of the foregoing floating matter in the extract obtained after immersing it in hot water when the resulting extract is cooled and has good transparency, but when the polypropylene resin composition is irradiated with radiant rays for sterilization thereof, a difference between pH values observed before and after the irradiation with radiant rays in the promoted hot water-extraction test and pH shows a substantial reduction after the irradiation with radiant rays. For this reason, a problem arises if the composition is used for making containers which are irradiated with radiant rays for sterilization and which accommodate aqueous solutions.
Thus, there has not yet been proposed any polypropylene resin compositions which has good transparency and simultaneously does not cause deterioration of contents to be accommodated.


A non-human animal carrying a disruption of a gene encoding a lyn protein tyrosine kinase provides a convenient system for the study of diseases associated with or caused by lyn deficiency, and for the testing of therapeutic agents for the treatment or prevention of diseases which include autoimmune diseases, allergy, asthma and malignant disease.

For many tissues of the body, ordered growth requires that the balance between cell production, cell differentiation and cell death is precisely regulated. Among the best studied of the rapidly-turning over tissues is the haematopoietic system, in which a multitude of terminally-differentiated cell types is generated from a relatively small number of stem cells and committed progenitor cells. Many of the factors which participate in the regulation of this process are known, thanks to data largely generated using in vitro systems. Recently, it has been possible to use gene targeting in embryonic stem cells (ES cells) to generate mice deficient in growth regulators, in order to examine whether these growth regulators indeed play a pivotal role in the regulation of normal blood cell production. See International Patent Application No. WO 95/23862 (PCT/AU94/00103).
Cells of the immune system are subject not only to regulation by a variety of growth factors and cytokines, but also utilise a complex system of signal transduction to mediate cell activation following antigen stimulation.
In particular, the src family of protein tyrosine kinases has been implicated in cell signalling through the physical association of these kinases with different cell surface receptors which on their own lack intrinsic catalytic activity (Bolen et al, 1992). Like several other members of the src family, the protein tyrosine kinase known as lyn is expressed in a broad range of cell types and tissues (Bolen et al, 1992). Largely through co-precipitation studies, lyn has been shown to be physically associated with a number of haematopoietic cell surface receptors, including the B cell antigen receptor (BCR) (Yamanashi et al, 1991; Burkhardt et al, 1991; Campbell and Sefton, 1992), CD40 (Ren et al, 1994), the lipopolysaccharide (LPS) receptor (Stefanova et al., 1993), the high affinity Fc.epsilon.RI complex (Eiseman and Bolen, 1992), and the G-CSF receptor (Corey et al, 1994). In most cases, more than one member of the src family has been found to be associated with the same cell surface receptor, raising the possibility of functional redundancy within the src family. This notion is supported by the milder than expected phenotype shown by mice in which one or other src-related kinase genes has been disrupted by homologous recombination in embryonic stem (ES) cells (reviewed in Varmus and Lowell, 1994). However, mice in which the lyn gene is disrupted have not hitherto been described.
A competent, signal-transducing BCR consists of an antigen-binding membrane immunoglobulin (Ig) non-covalently associated with disulphide-linked heterodimers of Ig-.alpha. and Ig-.beta./.gamma. subunits (Reth, 1992). While the molecules that make up this BCR complex lack intrinsic catalytic activity, stimulation of resting B cells with antibodies to membrane Ig induces rapid tyrosine phosphorylation of B cell proteins, suggesting associated tyrosine kinase activities (Gold et al, 1990; Campbell and Sefton, 1990; Gold et al, 1991). This increase in total cellular tyrosine phosphorylation is correlated with an increase in the enzymatic activity of several members of the src family, including lyn, blk, fyn, and fgr; indeed, co-immunoprecipitation studies have shown a physical association between the BCR complex and several members of the src family (Yamanashi et al, 1991; Burkhardt et al, 1991; Campbell and Sefton, 1992; Wechsler and Monroe, 1995). A highly conserved motif, termed the immunoreceptor tyrosine-based activation motif (ITAM), is found in many signal transducing subunits, including the cytoplasmic domain of the Ig-.alpha. and Ig-.beta./.gamma. molecules. Conserved tyrosine residues within this ITAM are a target for phosphorylation upon ligation of the BCR, and presumably provide docking sites for additional molecules involved in B cell signalling, such as PI 3-kinase, PLC-.gamma.2 and GTPase-activating protein. Recent studies have shown that the cytoplasmic domain of the Ig-.alpha. chain is constitutively associated with the src family kinases lyn and fyn (Clark et al, 1992; Pleiman et al., 1994a). This suggests that members of the src family may directly phosphorylate the ITAMs, and thus participate in very early events in the BCR signal transduction cascade.
Signalling events from the BCR resemble those thus far characterised for the Fc.epsilon.RI complex (Ravtetch, 1994). Fc.epsilon.RI is a tetrameric structure consisting of a ligand binding .alpha. subunit, a .beta. subunit and homodimeric .gamma. subunits (Blank et al, 1989). Like the Ig.alpha. and Ig.beta./.gamma. signalling molecules of the BCR complex, the cytoplasmic domains of the .beta. and .gamma. subunits of Fc.epsilon.RI also contain ITAMs (Ravetch, 1994). Biochemical studies have shown that lyn is associated with the .beta. subunit, and it is thought that on Fc.epsilon.RI triggering, lyn becomes activated and phosphorylates critical tyrosine residues in the ITAMs of both the .beta. and .gamma. subunits. The phosphorylation of the .gamma. subunit recruits and activates p72syk, which in turn activates other molecules involved in the signal transduction cascade (reviewed in Ravetch, 1994).
To gain an insight into the physiological role of lyn and to gauge its importance in relaying signals from these different cell surface receptors, we have generated mice which are unable to express lyn (lyn -/- mice) by gene targeting in ES cells. Our results show that lyn is an indispensable component of the BCR and Fc.epsilon.RI complexes, and that its actions are required for the elimination of autoreactive antibodies. In addition, our longitudinal studies of lyn -/- mice show that the absence of the lyn gene is associated in the long term with depletion of lymphoid tissue, extramedullary haematopoiesis, expansion of cells of the myeloid lineage, glomerulonephritis leading to renal failure, and lesions in spleen, lymph node, liver and kidney resembling malignancy. Consequently the lyn -/- mouse is useful as a model of autoimmune disease, especially autoimmune glomerulonephritis, and of certain malignancies or dysplasias of myeloid origin, such as myeloid leukemia, malignant histiocytoma, and histiocytosis.

Mice with targeted tyrosine kinase, lyn, disruption


Methods and systems vary the elevation beam pattern during an imaging session. A user based or automatic search mode is provided where one or more elevation beam thicknesses are used, and then a diagnosis mode is provided where an optimal or narrow elevation beam thickness is used for continued imaging. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data responsive to the varied elevation beam pattern.

The present invention relates to ultrasound imaging with multi-dimensional transducer arrays. Multi-dimensional transducer arrays may provide an adjustable narrow elevation focus. For example, 1.25D, 1.5D or 1.75D arrays are used to acquire data representing a scan plane. Rows of elements along the elevation dimension are used to electronically or mechanically focus the transmitted energy in the elevation dimension, increasing resolution. For different imaging frequencies, different elevation thicknesses may be provided.

This patent is subject to a terminal disclaimer.

Elevation beam pattern variation for ultrasound imaging


A reactor core with each fuel rod surrounded by an individual cylindrical channel is disclosed. This individual channel on each fuel rod provides thermal hydraulic and heat transfer advantages to enable all fuel rods within the fuel bundle to uniformly approach their own thermal limits. The preferred fuel rod pitch is a triangular pitch between the individual fuel rods as they are discretely surrounded by their own channel. The new triangular geometry provides for more uniform (flat) power distributions within all fuel rods--and hence all groups of fuel rods. Bypass flow is introduced uniformly between the fuel rod channels, rather than heterogeneously in the channel gap and water rods as in present BWR fuel designs. Individual fuel rod channels can be orificed differently, as required, to match inlet flow to fuel rod power output to maintain uniformity between all fuel rods as they approach their respective thermal limits. Gaps between bundles can be eliminated, or at least minimized, yielding even higher power density. Spacers with flow diverting structure vanes are applied within the fuel rod channel to limit relative displacement between the channel wall and fuel rod cladding and to serve as turbulent flow promoters.

Problem Statement
Boiling water reactor power densities have been limited in the past to less than 56 kilowatts per liter (KW/1), primarily as a result of their original designs. These designs constrain the power outputs of these reactors due to thermal limits and stability considerations. Thermal limits include the maximum linear heat generation rate and the minimum critical power ratio.
The maximum linear heat generation rate (MLHGR) is that maximum amount of heat output by a lineal foot of fuel rod. Normal MLHGR rates for a boiling water nuclear reactor are in the range of 12.1 to 14.4 Kw/ft (or, 40 to 47 Kw/m using purely metric units). Simply stated, the MLHGR is a limitation established by the fuel pellet swelling establishing a mechanical interference with the cladding containing the fuel rod. The MLHGR cannot be exceeded at any individual fuel rod within a fuel bundle without potential damage to that particular fuel rod within the fuel bundle. As no individual rod is permitted to be damaged within a fuel bundle, the entire bundle is limited in its performance to maintain the maximum linear heat generation rate in any given fuel rod location. It is to be understood that to the extent a particular bundle constituting part of a reactor core is limited in its output, the entire core is likewise limited.
The minimum critical power ratio (MCPR) is the ratio of that level of fuel bundle power at which some point experiences transition from nucleate to film boiling compared to the then present output of the fuel bundle. This ratio is not permitted to be less than a numerical value of one anywhere within an individual fuel bundle. If the limit were to be exceeded at any given location within the fuel bundle, the temperature of the cladding of the fuel rod would rapidly increase due to increased resistance in the heat flow path from the interior of the fuel rod to the exterior of the fuel rod. Potential failure of the particular fuel rod cladding could follow.
The concept of a ratio is utilized in establishing limits of critical power within the fuel bundle. The ratio is maintained at a limit where operating conditions--both expected in normal operations and during anticipated abnormal operating occurrences or "transients"--can occur without running the risk of damage to the sealed fuel rods within the reactor.
In already designed nuclear reactors, these thermal limits are largely established by the original design. There is, however, a need to increase the power output density of nuclear reactors of new manufacture.
Accordingly, the factors relating to the power output densities will be briefly reviewed. Conventional fuel designs will be briefly discussed, especially insofar as they incorporate many heterogenous distributions in their neutron density and related power output. Thereafter, reference will be made to certain new reactor designs.
Regarding the factors relating to increasing power densities, vessel sizes are limited in diameter to approximately seven meters, given the desire to continue to use forging to manufacture such vessels in existing manufacturing facilities capabilities. There exists a reluctance to expand vessel fabrication facilities beyond existing size limits under present market realities. Therefore, each reactor vessel is practically limited in its diameter. This requires that the number of fuel bundles within a BWR core is therefore limited.
Limitations also exist in establishing the active fuel length of fuel rod bundles since as fuel rod length increases, thermal margins and stability become of concern. The longer the fuel bundle, the greater the possibility of transition boiling unless considerable additional inlet coolant flow is provided. This is aggravated, however, by the higher fuel bundle pressure drop associated with increased length and inlet flowrate. Further, stability at certain power rates requires rods be maintained short. If the boiling length is too long and the two-phase pressure drop too high, thermal-hydraulic, and thermal-hydraulic-nuclear instabilities arise. As a practical matter, the active fuel length is limited to about 12.5 feet (or 3.81 m using metric units).
Once it is understood that both vessel diameter and fuel rod length are limited as a practical matter, it becomes clear that the total reactor volume available in any given reactor vessel approaches a limit. Therefore, the practical volume limit for a reactor is about 100,000 liters.
When a reactor is built, many costs are fixed and constant regardless of the power output of the installed plant. If the installed plant can have a higher power density, these fixed and constant costs become substantially more efficient.
Thus, there is a need for a new fuel design approach with potential to achieve higher power density to reduce the capital costs of nuclear reactors. This will enable any given reactor to have higher power output.
The forced circulation boiling water reactor is one alternative reactor that is able to achieve the higher power density requirements. Simply stated, such reactors--by forcing the flow of coolant along internal paths--have the ability to concentrate more power in a given plant location.
A new concept boiling water reactor which boils all of the entering coolant to steam and then superheats the steam is another reactor which can benefit from the use of this fuel design. See my copending patent application entitled "STEAM COOLED NUCLEAR REACTOR WITH BI-LEVEL CORE", Ser. No. 07/681,246, filed Apr. 4, 1991, which is incorporated herein by reference.

Fuel design for high power density boiling water reactor


An investment system provides for multiple employers. The employers withhold payments to employees according to preferences defined by the employee. The employer forwards the withholding to an investment account manager who manages accounts for each employee. The account manager pools the withholding from the employees and invests the money in proportion to the preferences stated by the employees in the plan. Employees may change employers without affecting their accounts. Tax information may be calculated by the system to ensure accurate gratuity accounting and tax compliance on the part of the employer.

1. Technical Field
This invention relates in general to financial systems and, more particularly, to a financial system for low-wage or transitory workers.
2. Description of the Related Art
Every wage earner has a need to invest at least a portion of his or her earnings. Many workers are able to invest money in a retirement plan and/or other investment vehicles. Retirement plans provide at least two significant benefits to participants. First, for people who have trouble saving money, a retirement plan can take an agreed upon amount from the participant's paycheck, thereby automatically providing discipline. Second, even for people who are diligent savers, money can be invested in stocks and bonds that historically have a greater rate of appreciation than simple interest provided by a savings account or certificate of deposit.
Nonetheless, many employers do not provide investment options to their employees. This is particularly true for certain categories of workers, particularly low-wage or transitory workers. Restaurant employees are typical of this worker category, although other groups, such as hotel workers and salespeople, would fall into this category as well, since a large percentage of their earnings come from gratuities/commissions, rather than wages, and because they switch jobs frequently. Even if a restaurant worker was diligent about saving money, the opportunities for investment would be limited to relatively small amounts of money and very few investment advisors would be interested in maintaining such a small account. Additionally, many workers accrue credit card and other debts that may charge significant interest. Without a savings strategy, it is difficult to retire this debt.
Many workers also have difficulty in saving to meet their tax liability. In areas where employees receive a significant amount of income through gratuities, saving is particularly difficult, since much of the worker's income is received in cash for each shift they work and, hence, is never deposited in a bank. For many years, it has been suspected that cash tips are under-reported—i.e., that some employees do not report the full amount of cash tips, which are not documented by the employer. Recently, it was ruled that the employer can be liable for taxes on estimated under-reported income. For example, if the Internal Revenue Service estimates that cash tips for a restaurant should be 14%, and the restaurant has reported less than that for its employees, then the restaurant is liable for the taxes on the difference.
Accordingly, a need has arisen for an investment system that accommodates the transitory and low wage workers. Further, a need has arisen for a cash reporting, collection, tracking and management investment system that withholds and reports a proper amount of income associated with gratuities.

System for savings and tax management of gratuity income


The semiconductor memory device includes a memory cell array including a plurality of cell transistors, and a page buffer configured to perform an verification operation for verifying a program state of a selected cell transistor by sensing a voltage of a sense node connected to a selected bit line of the memory cell array through a bit line selection transistor, wherein a logic level corresponding to a voltage of the selected bit line is constantly maintained regardless of the program state of the selected cell transistor during the verification operation.

The present invention relates to a semiconductor device and a method of operating the semiconductor device.
A semiconductor memory device includes a memory cell array which includes a plurality of memory cells. A connection relation or an arrangement method of the memory cells is varied depending on the type of semiconductor memory device. For example, in a NAND flash memory device, the memory cells are connected in series to constitute a cell string, and the cell string is connected between a bit line and a common source line.
FIG. 1 schematically illustrates a cell string 120 and a page buffer 110 connected to the cell string 120 of a NAND flash memory device in the related art, and FIG. 2 schematically illustrates a read operation of the page buffer 110 illustrated in FIG. 1.
Referring to FIGS. 1 and 2, the page buffer 110 includes a PMOS transistor MP pre-charges a sense node SO in response to a pre-charge bar signal PRECHb, an NMOS transistor MN selectively connects a bit line BL to the sense node SO in response to a bit line signal BSL, and a latch 112 temporally store data corresponding to a potential of the sense node SO. The page buffer 110 is connected to a cell string 120 through the bit line BL.
The cell string 120 includes a plurality of cell transistors MC1 to MCn. When a read voltage is applied to a word line WL2 and data stored in a selected memory cell MC2 is read, the page buffer 110 verifies the data stored in the selected memory cell MC2 as follows.
First, the sense node SO is pre-charged with a voltage PB_VREF, and then, a drain selection transistor DST, a source selection transistor SST, and the remaining cell transistors MC1 and MC3 to MCn, except for the selected cell transistor MC2, included in the cell string 120 are all turned on. Accordingly, when the selected cell transistor MC2 is turned on according to a voltage applied to the word line WL2, a current path is formed, so that a bit line current IBL flows. Particularly, when the selected memory cell MC2 is in a program state, the cell transistor MC2 is in an off state, so that a voltage level of the sense node SO is constantly maintained in the pre-charge voltage PB_VREF. When the selected memory cell MC2 is in an erase state, the cell transistor MC2 is turned on and thus a discharging current IBL flows, thereby decreasing the voltage level of the sense node SO. According to the voltage level of the sense node SO, data is stored in the latch 112.
When a voltage level of the bit line BL is decreased in the read operation, the current IBL flowing through the bit line BL, i.e., the current flowing through the selected memory cell MC2, may be decreased. As a result, there are some concerns that a threshold voltage of the selected memory cell MC2 may be verified to be larger than an actual threshold voltage, thereby finally resulting in malfunction of the semiconductor memory device.

Semiconductor memory device having page buffer and method of operating the same


A steering spindle arrangement having a first component remote from the steering wheel and a second component near the steering wheel, with one of the mutually facing ends of the one component dipping into the hollow end of the other component, and with the two ends being connected frictionally to each other, is disclosed. Furthermore, a method for producing the arrangement is disclosed. In order, in a simple manner, to obtain as specific a definition as possible of the absorption by the steering spindle of the deformation energy in the event of a crash while ensuring that the arrangement is durable and directly transmits the steering moment, it is provided that the walls of the two ends lie directly on each other in the form of a press fit over the region of the frictional connection.

The invention relates to a steering spindle arrangement and to a method for producing it.
A steering spindle arrangement of generic type and a production method of the generic type are disclosed in German Patent Document No. DE-A 14 30 946. The arrangement which is described comprises two telescopic steering spindle components which are fixed frictionally on each other, with the steering moment transmitted by the steering wheel to the inner component being passed on to the outer spindle component by the frictional connection. If there is an axial impact in the event of a crash, the two components are pushed one inside the other, with impact energy being consumed by the friction. The frictional connection is formed in different ways, namely, first, by means of a tolerance ring which is arranged in a groove on the inner circumference of the outer component and, secondly by a plastic layer which is placed in the plug-in position of the components and imparts the frictional connection between the components. As a further variant, those ends of the components which communicate with each other have spring-loaded form-fitting elements which are provided with bevels, engage one inside the other and, in the use position of the components, are caused by the compression spring to slide on the bevels in such a manner that a radial pressing of the inner component against the outer component is produced. In addition, those ends of the components which are connected to each other are locked in a form-fitting manner in the circumferential direction by means of their polygonal shape, as a result of which the steering torque can be transmitted even better.
However, one disadvantage of the known arrangement is that the arrangement of a tolerance ring is relatively complicated, since the latter has to be specially adapted to the cross-sectional dimensioning of the outer steering spindle component and requires a securing device (receiving groove) which complicates the production of the steering spindle. Furthermore, the tolerance ring itself has manufacturing tolerances which, in comparison to the individual steering spindles, result in the travel of the inner component being dispersed and therefore to different levels of energy absorption in vehicle collisions. This means that—contrary to the required safety conditions—it is not possible to establish a specific, uniform safety standard for the steering spindle from the outset. The plastic-layer variant shown is less practicable, since the plastic layer wears very rapidly and over time transmits the steering moment very imprecisely to the outer component, which results in a risk to the driver. In addition, the method for producing the frictional connection with the layer is awkward, since the layer has to be placed over a very narrow annular gap between the spindle components. This means a method step for producing the connection, in which it cannot be assessed whether the layer is completely formed and can thus provide the expected frictional connection level. The other variant having the bevelled form-fitting elements is also very complicated in terms of the design and installation. In addition, in a crash the driver might be subjected to a spontaneous, unbraked impact, since the form-fitting element of the other component is fastened to it and thus prevents displacement of the inner component.
The invention is based on the object of developing a generic arrangement to the effect that, in a simple manner, as specific a definition as possible of the absorption by the steering spindle of the deformation energy in the event of a crash is obtained while ensuring that the arrangement is durable and directly transmits the steering moment. Furthermore, it is the object of the invention to develop a generic method for producing the arrangement to the effect that it can be carried out with only a little outlay and reliably.
Owing to the invention, all of the structural elements which impart the frictional connection between the inner and outer steering spindle components are omitted in the arrangement. This simplifies the construction of the arrangement on account of the reduction in the number of parts. Furthermore, no manufacturing tolerances and/or wear of the structural elements arise, with the result that a specific definition of the absorption by the steering spindle of the deformation energy in the event of a crash is possible. The press fit produced by pressing together the two steering spindle components can be reliably produced with little outlay by various methods, for example by magnetic pulse deformation or thermal shrinking-on of the outer component in the plug-in position of the two components. The direct contact of the component walls against each other results in direct transfer by the arrangement of the steering moment. The press fit furthermore ensures that the arrangement is durable in normal operation and is able, owing to the high frictional force of the joining partners, i.e., the two steering spindle components, to absorb large displacement forces in the event of a crash. The frictional connection can be set in a specific manner by selecting the process parameters of the production methods, with it being possible for a certain axial displacement force to be established for a crash situation and hence for a uniform force profile to be produced. This selection enables the force profile to be varied as desired in accordance with requirements.

Steering spindle arrangement and a method for the production thereof


A method is described for producing recombinant eukaryotic cell lines expressing multiple proteins of interest. Eukaryotic host cells are transfected with (a) a first episome which contains an EBV origin of replication and a first gene encoding a protein of interest; and (b) a second episome containing an EBV origin of replication and a second gene encoding a protein of interest. Transfected cells are obtained expressing an EBNA 1 protein. The cells are grown under conditions wherein the episomes express the first and second genes.

In the field of molecular biology it is often desirable to transfect cells to express multiple genes. Classical methods for achieving this have relied upon integration of multiple genes into one or more chromosomal loci. The sites of gene integration, however, are random, and the number and ratio of genes integrating at any particular site are unpredictable. Therefore every transfected cell is unique. Furthermore, expression of the integrated genes may be subject to unpredictable position effects, e.g., those caused by adjacent chromosomal sequences. In some cases, amplification of the genes of interest is required in order to achieve adequate expression levels. As a result, it is normally necessary to screen many clonal cell populations to obtain a cell line in which all of the desired genes are expressed at an appropriate level. This procedure of transfection, selection and analysis of numerous clonally derived cell lines expressing the multiple genes can take many months.
For example, simultaneous transfection of HEK293 cells with vectors encoding the .alpha.1, .alpha.2, and .beta.3 subunits of human calcium channel has been carried out to obtain fully functional expression of that multi-subunit protein from chromosomally incorporated copies of the transfected genes. However, obtaining cells that functionally express all three subunits requires extensive screening of cell populations, while finally obtaining very few colonies (Buchert et al., Biotechniques (UNITED STATES) 23, 402-407, 1997).
Non-integrating, autonomously replicating episomal vectors have been used to transform cells to express a gene of interest. In particular, the Epstein Barr Virus (EBV) Nuclear Antigen 1 (EBNA 1) has been used to stably maintain a plasmid containing an EBV origin of replication (oriP) in primate cells (Reisman, D. et al, Mol. Cell. Biol. 5: 1822-1832, 1985; Yates, J. L. et al., Nature 313:812-815, 1985). The plasmid is maintained in an episomal state, i.e., it is not integrated into the chromosome.
Transfection of cell lines that express EBNA 1 can be advantageous since the ability of such cells to stably maintain an episomal construct can be enhanced by several orders of magnitude, and stable cell lines can be generated in as little as two to three weeks. For example, HEK cells that stably express EBNA 1 have been transformed with plasmids containing the EBV origin of replication, and the gene encoding CRHR1 (corticotropin releasing hormone receptor subtype I). The resulting cell lines have been found to stably express high levels of CRHR1. (Horlick et al., Prot. Exp. And. Purific. 9:301-308, 1997.)
Similarly, U.S. Pat. No. 4,686,186 describes transfecting cells with a single plasmid containing the EBV oriP, the EBNA 1 gene, and a gene encoding a protein of interest (U.S. Pat. No. 4,686,186).
Expression of multiple genes on a single plasmid, however, can result in promoter occlusion. (Greger, I. H. et al., Nuc. Acid Res. 26(5): 1214-1301, 1998; Kadesch, T. et al., Mol. Cell. Biol. 6(7): 2593-2601, 1986). In cases of promoter occlusion, one strong promoter can bind most or all of the transcription factors in its immediate vicinity, thereby limiting transcription from other promoters present in cis on the same plasmid. This, in turn, causes the expression of multiple genes of interest on a single episome to be unpredictable and often problematic (Horlick et al., 1997). The EBNA1/oriP expression system has not, therefore been widely used to express multiple genes of interest.
Currently, each cell type for which episomal expression is desired is typically first transfected with an integrating copy of the gene encoding EBNA 1. Since developing cell lines that constitutively express EBNA 1 from an integrated gene is time consuming, current methods are somewhat limited in their applicability to different cell lines. Programs for mass screening of compound libraries require use of many types of cell lines, and producing EBNA 1 producing strains of each type by this method requires an extensive effort.
Alternately, episomes that already carry the EBNA 1 gene and a gene of interest in cis on the same episome can be used to transfect cells. Commercial vectors such as pCEP4 (Invitrogen) are available for this purpose. However, current vectors in which EBNA 1 is carried by the episomal construct in cis do not contain a known promoter for driving expression of EBNA 1. Rather, it is believed that transcription of the EBNA 1 gene occurs from a fortuitous promoter situated in or near an amp resistance marker that is located a few hundred nucleotides upstream from the EBNA 1 start codon. This fortuitous promoter, however, is not sufficiently recognized by differing cell types to consistently express EBNA-1 with sufficient speed and abundance to sustain the replication and maintenance of the episome (before it is otherwise lost from the cell). Therefore, currently available episomal vectors containing the EBNA 1 gene in cis do not appear to provide sufficient reliability for use in a wide variety of cell types. Furthermore, adding a strong promoter to these episomes to express the EBNA-1 gene in cis would, under certain circumstances, result in promoter occlusion.
Multiple plasmids have been used to transform bacterial cells. However, to the inventors's knowledge, transfection of eukaryotic cells with multiple plasmids has not been described. Furthermore, it has not been known whether transfecting a eukaryotic cell with a second or third episome would disrupt an already resident first episome. For example, it has not been known whether transfection of separate episomal constructs into eukaryotic cells would result in stable maintenance of both constructs, or in efficient transcription or translation of separate genes contained in both constructs.
There is therefore a need for a method that allows rapid production of eukaryotic cells that stably express multiple genes.
There is also a need for a method that allows rapid production of stable cell lines of varying types that express a gene of interest.

Eukaryotic cells stably expressing genes from multiple transfected episomes


An instantly playable stringed instrument having a body, neck and fret spaces is provided. The instrument includes a plurality of strings. The strings are tuned such that in combination the sound they produce is an open E minor chord. The instantly playable stringed instrument may further include a plurality of indicators, each indicator corresponding to one fret space. Each indicator indicates a minor chord to be played by depressing all the strings within the fret space the indicator is associated with. The stringed instrument may further include a minor third string that has a color identification to distinguish it from the rest of the plurality of strings. The minor third string may be depressed on an adjacent fret space thereby converting the minor chord associated with the fret space having all strings depressed to a major chord.

1. Technical Field
This invention relates generally to a stringed instrument and more particularly to an instantly playable stringed instrument that enables a player to instantly and with reduced effort play every chord available with the use of one, two or three fingers.
2. State of the Art
Guitars have been around for centuries in various forms, shapes and sizes. The guitar that is commonly known by people of today, the six string guitar, took on its modern shape and dimensions beginning in the early nineteenth century. The guitar has become a popular instrument that many people love to play and many more would like to learn how to play.
Conventional guitars, as well as other conventional stringed instruments, such as but not limited to ukuleles, banjos and bass guitars, require some form of lessons in order to play chords on the instruments. These lessons come in various forms, such as live instruction from a guitar teacher, video instruction, interactive CD instruction, and instruction books and lesson manuals, for example. Learning even the basic chords can at times be challenging and take more time than a person may initially anticipate. Due to the notes that each string of the guitar is tuned to, the chords are set as to how they may be played and the finger positions are not always intuitive and at times difficult for beginners. In addition, the conventional guitar may utilize several completely different and often very difficult finger-configurations for the same chord, which serves to further complicate the learning and increase the difficulty of mastering sonic clarity.
Accordingly, what is needed is a guitar that can be instantly played by any person without the need for lessons.

Instantly playable stringed instrument and method of use thereof


A pivotable toilet flush valve member (10) is provided, of the type that includes a float (40) with a pair of holes (44, 52) that allow the float to fill with water during a flushing to close early, and where the float can be turned to vary the amount of water used during a flushing, wherein the float is constructed for easy and loose mounting on a frame (12) and for low friction rotation about a primarily vertical axis (60), and where the flush valve member has a simple detent mechanism to hold the float at any rotational position to which it is turned. The frame has an aperture (74) lying along the primarily vertical axis, and the float has a small diameter upwardly extending projection (70) that projects upwardly through the frame aperture and that is held by the walls of the aperture, for low friction turning. The detent mechanism includes an upstanding wall (100) with an upwardly-open vertical groove (102) that has a plurality of teeth on at least one side of the groove. The frame has a downwardly-extending detent (92) with at least one tooth (111-113) that lies in the groove.

A common type of toilet flush valve member includes a float device with a float and seal, lying at the outer end of a yoke or frame, with the inner end of the frame pivotally mounted about a horizontal axis. When a chain initially pulls the float up to start a flushing, the buoyancy of the float keeps the flush valve member raised until almost all water has exited the tank. Then the flush valve member pivots down and its seal seals against a valve seat while the tank is refilled with water. Most toilets in present use, dispense about three gallons of water in each flushing. Municipalities wish to reduce the amount of waste water that passes through drain pipes and that must be treated before discharge. This can be accomplished by reducing the amount of water dispensed in each flushing.
One approach to reducing water usage, includes providing a second hole in the float, in addition to the drain hole at the bottom of the float. When the flush valve pivots up during a flushing, the second hole allows air to escape from the float chamber while water flows into the float chamber. This progressively decreases the buoyancy of the float, until it becomes heavy enough and closes the flush valve when perhaps only two gallons instead of three have been dispensed.
When setting up the new flush member, it is desirable to be able to adjust, in small increments, the amount of water dispensed in each flushing. This can be accomplished by allowing the float to be turned about a vertical axis, so the vertical height between the air escape hole and the usual water drain hole in a raised flush member can be varied. U.S. Pat. No. 4,419,773 by Sullivan describes an adjustable flush valve member of this type, wherein the frame is provided with a large diameter flange at its periphery, that lies in a horizontal plane (when the valve is lowered). The float device is provided with a groove at its periphery that includes walls lying below and above the flange to enable the float to turn about the flange. Also, the walls of the groove include teeth that are engaged by a detent on the frame to hold the float at any rotational position to which it is turned. While this approach enables fine adjustment of the float rotational position, it can result in difficult mounting of the float device on the frame, rigidizing of the float device seal and possible leakage, and difficult turning of the float device. The enlarged diameter of the rotation joint where the float device is rotatably coupled to the frame, results in high friction against float rotation and the possibility that there can be a "jamming" that makes it difficult to turn the float device. Turning of the float device can be especially difficult because it usually lies at the bottom of a wet tank. A flush valve member whose closing delay is adjustable by turning a float device, wherein float turning occurred with relatively low friction while the float was securely held in any of a plurality of rotational positions, and with the float device being easily mounted on the frame in a"loose" coupling that permitted float device tilt, would be of value.


The present invention provides to a method and apparatus for minimizing or preventing negative current build up in DC-DC converters with synchronous rectification. The method turns the first synchronous rectifier off when the negative current is present in the first secondary winding and the first synchronous rectifier is on, and turns the second synchronous rectifier off when the negative current is present in the second secondary winding and the second synchronous rectifier is on.

The present invention relates generally to the field of logic integrated circuits and, more particularly, to a new DC-DC converter with synchronous rectification that prevents or minimizes negative current build up.
The supply voltage of integrated circuits used in electronic devices, such as computer and communications equipment, has decreased from 5 volts to 2.5 volts or, in some cases, to 1.5 volts. Since the number of transistors in these integrated circuits has increased, the output current demand of the DC-DC converters has increased accordingly. The low output voltage DC-DC converter with the traditional Schottky diode rectifiers suffers from low efficiency and high power loss. Synchronous rectification technology has improved the efficiency of DC-DC converters significantly, especially as related to the low voltage output. However, the synchronous rectification has added more complexity to the DC-DC converter circuit. It has also made the system design more difficult because the DC-DC converter with rectification can sink current from secondary to primary. Because of this, the synchronous rectifiers have a common problem: they need a parallel tool converter, such as O-ring diodes, to allow parallel connection of the converters. Without the O-ring diode, one converter can sink the current from another converter, possibly destroying the second converter because the current can go as high as 20 or 30 amps. The O-ring diode restricts the direction of the current. However, the O-ring diode decreases system efficiency.
One technique to prevent the synchronous rectifier DC-DC converters from sinking current from the secondary involves monitoring the current through the synchronous rectifier. When this current reaches a predefined level, the converter turns off its synchronous rectifier and then relies on the body (switch) diode to conduct current. This technique works very well, but adds complexity to the circuit. Accordingly, there is a need for a simple circuit that will minimize or prevent the converter from sinking current.
The present invention provides a new circuit to enable to parallel the bridge type DC-DC converter with synchronous rectification. It is applicable to various types of DC-DC converters, including push-pull, full bridge and half bridge. The present invention provides a simple circuit that will minimize or prevent the converter from sinking current. As a result, the present invention eliminates unnecessary power dissipation, reduces potential damage to the converter and allows parallel operation of the converters. Although the present invention is described below in reference to a half bridge rectifier, the present invention can be implemented for full-bridge and push-pull topologies. In addition, the present invention is particularly useful in portable electronic devices, such as computers, personal data assistants and communication devices.
As an example, the operation of the present invention is described in relation to a half bridge DC-DC converter. When there is no load on the secondary, the average current through the output inductor is zero. In the free wheeling stage, both synchronous rectifiers are on, allowing the inductor current to flow in the negative direction. When there is a voltage source higher than the converter""s regulated voltage, the converter tries to reduce its duty cycle. Therefore, the primary MOSFET is turned off and the secondary MOSFET is turned on. At this point, the secondary rectifiers operate as if they are in the free wheeling stage. The duty cycle of the off state for the primary MOSFET is longer than the normal operation, allowing the inductor current to build up in the negative direction. The current in the transformer flows in the negative direction with respect to its normal operation. Once the primary MOSFET is turned off, the current flows through its body diode. At this time, the polarity and magnitude of the transformer is the same as before. The converter is sinking current from the secondary to the primary. In order to prevent the converter from sinking current from the secondary, the current must not be allowed to build up in the negative direction. This can be accomplished by adding a pair of switches.
The additional switches turn off the synchronous rectifiers at the appropriate time to prevent the negative current buildup in the inductor. When the current feeds back from the secondary to the primary, the effective duty cycle of the transformer is actually higher than the duty cycle of the converter feedback from the primary. By using that condition as a signal to connect to a switch that pulls the gate voltage of the synchronous rectifiers low, the current feedback from the secondary to the primary can be kept from reaching a significant level. There may still be some feedback. However, it should not exceed a half amp. This enables paralleling without the O-ring diode.
The present invention thus provides a method for minimizing or preventing a build up of a negative current in a DC-DC converter having a first secondary winding coupled to a first synchronous rectifier and a second secondary winding coupled to a second synchronous rectifier by turning the first synchronous rectifier off when the negative current is present in the first secondary winding and the first synchronous rectifier is on, and turning the second synchronous rectifier off when the negative current is present in the second secondary winding and the second synchronous rectifier is on.
The present invention also provides a DC-DC converter having a DC source, a first capacitor and a second capacitor series coupled across the DC source, a first primary switch and a second primary switch series coupled across the DC source. A primary winding of a transformer is coupled between the first and second capacitors, and the first and second primary switches. A first and second secondary winding of the transformer are coupled together. A first synchronous rectifier is coupled between the first secondary winding and a ground, and a second synchronous rectifier is coupled between the second secondary winding and the ground. An external driver is coupled to and provides timing signals to the first primary switch, the second primary switch and a DC level shifter. A first totem pole driver is coupled between the DC level shifter and the first synchronous rectifier, and a second totem pole driver is coupled between the DC level shifter and the second synchronous rectifier. A first circuit is coupled to the external driver, a first totem pole driver and the first secondary winding wherein the first circuit turns the first synchronous rectifier off when a negative current is present in the first secondary winding and the first synchronous rectifier is on. A second circuit is coupled to the external driver, a second totem pole driver and the second secondary winding wherein the second circuit turns the first synchronous rectifier off when the negative current is present in the second secondary winding and the second synchronous rectifier is on.
Other features and advantages of the present invention will be apparent to those of ordinary skill in the art upon reference to the following detailed description taken in conjunction with the accompanying drawings.

Method and apparatus for minimizing negative current build up in DC-DC converters with synchronous rectification


A system for monitoring for gas and oil flow venting from a surface using time intervals, size and velocity, and using an analysis processor with a data storage containing a bubble flow classification and bubble flow categories. The data storage receives at least one of: video feed, logging while drilling data feed, seismic profile data feed, drilling parameter data feed, measurement while drilling data feed, sonar data feed, hydrographic data feed and a laser data feed to verify a determined bubble flow category and bubble flow classification as a baseline bubble flow classification and provides an alarm when a bubble flow emergency is ascertained due to a change in bubble flow classification without an anticipated change or changes outside predefined acceptable limits within the video feed, logging while drilling data feed, seismic profile data feed, drilling parameter data feed, measurement while drilling data feed, sonar data feed, hydrographic data feed and a laser data feed.

A need exists for a system for monitoring for gas and oil flow venting from a surface and to provide an early indication of subterranean formation problems by analyzing bubble size, time interval, and velocity for bubbles or globules venting from a surface.
A further need exists for a system for monitoring for gas and oil flow venting from a surface utilizing a data feed (e.g., video feed) and a bubble flow classification to create a bubble flow classification for the surface, and then, additionally, to verify the bubble flow classification results using the data feed in real time, 24 hours a day, 7 days a week, from a plurality of data feeds including, but not limited to, at least one of: a video feed, a logging while drilling data feed, a seismic profile data feed, a drilling parameter data feed, a measurement while drilling data feed, a sonar data feed, a hydrographic data feed and a laser data feed, and further to monitor bubble flow and classify additional bubble flow over time to verify that the baseline bubble flow classification of bubble flow is valid or another classification of bubble flow needs to become the new baseline bubble flow classification.
A need exists for a system for monitoring for gas and oil flow venting from a surface during marine drilling, development, or production operations.
A need exists for a system for monitoring for gas and oil flow venting from a surface that can create immediate alarms regarding potentially dangerous situations and transmit those remote alarms to client devices, such as through a network.
The present embodiments meet these needs.

System for monitoring a surface for gas and oil flow


To improve both the absolute measurement accuracy and the linearity of the characteristic function and the short-time repeatability of measurements at varying flow velocities, particularly at low flow rates, this electromagnetic flow probe (10) is designed to be immersed in a fluid flowing in a pipe (12), which is to be measured, the direction of immersion being virtually perpendicular to the direction of fluid flow. The probe is further designed to be passed through a hole in a wall of the pipe fluid-tight and comprises a circular cylindrical housing (11) having a predetermined outside diameter adapted to the bore. The front end (14) of the housing extends into the fluid and is closed fluid-tight by a front plate (14") of insulating material in the form of a calotte, which has a radius approximately equal to 1.2 to 1.5 times the outside diameter of the housing. A coil assembly (15) is disposed in the housing for establishing a magnetic field (16) extending through the front plate (14") into the fluid. A coil core (17') is disposed in the housing and made at least partially of soft magnetic material which ends at or near the front plate. A first galvanic electrode (18) and a second galvanic electrode (19) are disposed in the front plate on one of the meridians of the calotte and symmetrically with respect to a vertex of the meridian.

With such flow probes which can be inserted into the bore by means of, for example, an adapter provided therein, the velocity and, after suitable calibration, the volumetric flow rate of the fluid can be measured.
Unlike electromagnetic flow sensors, in which a coil assembly for producing a magnetic field passing through a measuring tube is fixed on the external surface of this measuring tube and in which at least two electrodes are provided in the wall of this tube, the electromagnetic flow probes according to the invention are inserted into a lateral bore of the measuring tube, for example, and fixed in the bore fluid-tight.
The need for the coil assembly on the external surface of the measuring tube is eliminated since the magnetic field exists only in the area of the front end of the probe, which extends into the fluid, or is produced in this area by a current flowing through the coil assembly.
U.S. Pat. No. 3,881,350 discloses an electromagnetic flow probe designed to be immersed in deep-sea water, i.e., in water under high pressures, which flows relative to the flow probe, the flow probe comprising:
a circular cylindrical housing having an outside diameter and a front end PA1 a coil assembly disposed in the housing for producing a magnetic field extending through the front plate into the fluid; PA1 a coil core disposed in the housing and made at least partially of soft magnetic material PA1 a first galvanic electrode and a second galvanic electrode disposed in the front plate on one of the diameters of the front plate and symmetrically with respect to the center of the diameter. PA1 which is designed to be immersed in a fluid flowing in a pipe, which is to be measured, the direction of immersion being virtually perpendicular to the direction of fluid flow, PA1 which is designed to be passed through a hole in a wall of the pipe fluid-tight, and PA1 which comprises: PA1 a circular cylindrical housing having a predetermined outside diameter adapted to the bore, PA1 a coil assembly disposed in the housing for establishing a magnetic field extending through the front plate into the fluid; PA1 a coil core disposed in the housing and made at least partially of soft magnetic material PA1 a first galvanic electrode and a second galvanic electrode which are disposed in the front plate on one of the meridians of the calotte and symmetrically with respect to a vertex of the meridian.
which is closed fluid-tight with a flat front plate of insulating material (this front plate referred to therein as "insulating wall"), and PA2 which is surrounded by a lenticular bead (referred to therein as "head"); PA2 which ends at or near the front plate; and PA2 the front end of the housing, which extends into the fluid, being closed fluid-tight by a front plate of insulating material in the form of a calotte, PA2 which ends at or near the front plate; and
It is obvious that because of the bead, this flow probe is not readily insertable into the bore of a pipe wall from outside fluid-tight. In the case of measuring tubes, however, but particularly in the case of installed pipes, this insertability from outside is mandatory. Thus, if the prior-art flow probe is used in a measuring tube and/or a pipe, its bead must be omitted.
Then, however, the front end of the electromagnetic flow probe terminates with the flat front plate, which must contain the electrodes. Since the fluid flows against the front end, vortices similar to those formed in vortex flow sensors are caused downstream of the front end.


A method and a system are provided for performing memory access assist using voltage boost. A memory access request is received at a storage cell array that comprises two or more subarrays, each subarray including at least one row of storage cells. The voltage boost is applied, during the memory access, to a first negative supply voltage of a first storage cell subarray of the two or more storage cell subarrays. The first negative supply voltage of the first storage cell subarray is lower than a second negative supply voltage of a second storage cell subarray of the two or more storage cell subarrays.

Static random access memory (SRAM) arrays are sometimes designed to include voltage assist circuitry to improve performance and/or reliability, enabling operation of the SRAM at a lower supply voltage. Specifically, voltage assist can improve the ability to read from and write to SRAM cells, and can prevent stored values from being inadvertently flipped during read and write operations. Existing assist mechanisms are typically applied to all of the storage cells in a memory array. This can result in the assist circuitry being relatively large and consuming a significant amount of power. Thus, there is a need for addressing the issue of access reliability and/or other issues associated with the prior art.

System and method for performing SRAM access assists using VSS boost


The present invention is directed to a method of preparing non-flammable thermal insulation foam, comprising the steps of (a) providing a mixture comprising (1) at least one water soluble alkali metal silicate, (2) optionally, at least one filler, and (3) at least one inorganic material which releases non-flammable gases when exposed to heat; (b) applying the mixture to a support or mold; and (c) heating the mixture to form the non-flammable thermal insulation foam.

1. Field of the Invention
The present invention is directed to foam insulation, and more particularly to a method of making non-flammable thermal insulation foam from water soluble alkali metal silicates and organic materials. The invention is also directed to a method of making nonflammable foam panels made from water soluble alkali metal silicates and filler additives.
2. Brief Description of the Related Art
Thermal insulation is known for use in houses, buildings, pipes, ductwork, and many other applications. The best known thermal insulation for structures is fiberglass insulation, sold commercially by Owens Coming (Toledo, Ohio). Although this thermal insulation is very popular, it possesses a relatively low "R" factor and reduced thermal insulating properties as it absorbs moisture. Fiberglass material may also be a health hazard. Likewise, urea-formaldehyde foam has been used for insulating cavities and structures. However, use of that foam was prohibited because of alleged health hazards.
Polyurethane and other petroleum-based foams have been used for many years and have substantially better R factors as compared to fiberglass insulation. However, petroleum-based foams suffer several disadvantages. First, they are flammable and can give off toxic fumes if burned. Second, since they are made from petroleum products, such materials are generally bad for the environment if they are not disposed of properly.
U.S. Pat. No. 5,035,951 discloses swellable materials that protect against overheating, comprising an aqueous mixture of a water soluble alkali metal silicate, a hydrated metal silicate clay, and an inorganic particulate material which, when exposed to flame temperatures, endothermically releases a nonflammable gas. The sodium and potassium silicates utilized in this coating have softening points of 1200 and 1280° F., and flow points of 1545 and 1660° F., respectively. This composition utilizes clay and other materials that give the composition the ability to withstand temperatures up to 3200-3400° F.
What is needed in the art is a foam insulation that possesses a high "R" value for insulation, that is nontoxic, nonflammable, and that is not bad for the environment. The present invention is believed to be an answer to that need.

Method of making non-flammable thermal insulatiion foam and products made by the method


A lamp body for a fluorescent lamp has multiple sections arranged on an inner surface of the lamp body. The sections include at least one coated section coated with fluorescent powders and at least one non-coated section being naked and kept free from fluorescent powders. The fluorescent powders generate visible lights when colliding with ultraviolet rays. The visible lights can directly pass out of the lamp body through the at least one non-coated section to form a light source and improve a luminance of the fluorescent lamp.

1. Field of the Invention
The present invention relates to a lamp body for a fluorescent lamp, and more particularly to the lamp body that can improve the luminance ratio of the fluorescent lamp.
2. Description of Related Art
A conventional fluorescent lamp has a lamp body, a positive electrode and a negative electrode. The lamp body is filled with mercury and inert gas and has two ends and an inner surface. The inner surface of the lamp body is coated with fluorescent powders. The positive electrode and the negative electrode are mounted respectively at the two ends of the lamp body. When the positive electrode and the negative electrode of the fluorescent lamps are connected to a power source and a high voltage are imposed between the positive electrode and the negative electrode, the mercury is vaporized and the negative electrode emits electrons to the positive electrode. The electrons collide with gas molecules of the vaporized mercury to generate ultraviolet rays. The ultraviolet rays are turned to visible lights after colliding into the fluorescent powders. The visible lights pass through the lamp body of the fluorescent lamp via gaps amount the fluorescent powders to form a light source.
However, the inner surface of the lamp body of the conventional fluorescent lamp is wholly coated with the fluorescent powders, so part of the visible lights inside the lamp body is reflected by the fluorescent powders and cannot pass through the lamp body. An appreciable proportion of the visible lights is repeatedly reflected inside the lamp body by the fluorescent powders, gradually decays and finally transforms into waste heat. Because part of the visible lights cannot pass through the lamp body, a luminance of the fluorescent lamp is lowered and inefficient.