Disclosed is a method for forming metal oxide dielectric layers, more particularly HfO2 dielectric layers, using an atomic layer deposition (ALD) method in which a series of thin intermediate layers are formed and treated with one or more oxidizers and nitrogents before the next intermediate layer is formed on the substrate. The intermediate oxidation treatments reduce the number of organic contaminants incorporated into the metal oxide layer from the organometallic precursors to produce a dielectric layer having improved current leakage characteristics. The dielectric layers formed in this manner remain susceptible to crystallization if exposed to temperatures much above 550° C., so subsequent semiconductor manufacturing processes should be modified or eliminated to avoid such temperatures or limit the duration at such temperatures to maintain the performance of the dielectric materials.

1. Field of the Invention
The present invention relates to an improved method for manufacturing semiconductor devices, and more particularly, to an improved atomic layer deposition (ALD) method for forming thin, high-quality HfO2 layers suitable for use as a dielectric material in such semiconductor devices.
2. Description of the Related Art
As the scale of semiconductor devices has decreased, the need for ultra-thin layers has gradually increased. However, the formation of ever thinner layers necessitates other process adjustments such as lower thermal budgets and the use of new materials. In addition to the thermal budget concerns, as the size of contact holes and other structural elements are decreased, problems associated with step coverage and loading effects tend to increase. Atomic layer deposition (ALD) methods have been proposed as a means for overcoming various problems resulting from the increased integration of semiconductor devices.
The basic ALD technique enables a material layer to be grown to a desired thickness by repeatedly forming very thin (i.e., atomic) layers of a desired material using two types of reactants sequentially applied to a reaction chamber. ALD techniques obtain an AB material layer by reacting minute quantities of two reactants, AX(g) and BY(g), on the surface of a substrate. The thickness of the AB material layer is increased by repeating the sequential supply and reaction of the AX(g) and BY(g) reactants generating XY(g) as a by-product. The deposition reaction can be generally represented by Formula I.AX(g)+BY(g)→AB(s)+XY(g)  I
More specifically, in an ALD process, a first reactant, AX(g), is supplied to a reactor chamber which a semiconductor substrate, such as a wafer, is provided. The first reactant AX(g) may be referred to as a "precursor" and is a compound obtained by combining an element A that will be used to form the desired AB material layer with another element or elements X. The first reactant AX(g), supplied to the reactor, may react with a surface of the substrate, or be chemically or physically adsorbed by the surface of the substrate. Here, since the absorption reaction can be regarded as the actual reaction, the first reactant layer of the chemically absorbed AX (or chemisorbed) is formed on the atomic-size level.
Next, the non-chemisorbed portion of first reactant AX(g) is removed from inside the reactor. This removal may be performed using vacuum exhausting or vacuum pumping. Alternatively, the vacuum exhaust process may comprise purging the reactor with an inert gas such as N2 or Ar. The purge cycle will remove substantially all of the physically-absorbed AX from the substrate and flush it, as well as any remaining non-absorbed first reactant AX(g) from the chamber. As a result, only the chemisorbed or reacted AX layer remains on the substrate.
A second reactant BY(g) is then supplied to the reactor. The second reactant B Y(g), which may also be referred to as a "precursor," is a compound obtained by combining an element B necessary to form the desired AB material layer with an element or elements Y. A portion of the second reactant BY(g) reacts with the chemisorbed layer of AX according to Equation I, thereby forming a thin "atomic" AB(s) layer on the substrate and generating the by-product XY(g). The non-reacted portion of the second reactant BY(g) and the reaction by-product XY(g) are then removed from the reactor, typically by vacuum exhausting and/or purging with an inert gas.
The resulting AB(s) layer is formed roughly on the atomic-size level and is, therefore, not more than a few molecules thick. Accordingly, to form the AB material layer having the desired thickness, the cycle of supply, exhaustion, and purging of the AX(g) and BY(g) reactants is typically repeated several times.
Of particular interest in the quest for ever thinner and high-quality are the capacitive dielectric layers that are conventionally employed as gate dielectric layers within field effect transistors (FETs) and capacitor plate separation dielectric layers used in various types of microelectronic fabrications, including, for example, the production of highly integrated semiconductor devices. The capacitance of a structure may be determined using Formula II:C=εin·A/Tin  IIwhere C is the capacitance, εin is the dielectric constant of the dielectric material, A is the surface area of the capacitor and Tin is the thickness of the dielectric material. As reflected in this formula, as the area available for use as a capacitor is decreased in more highly integrated devices, the dielectric constant must increase and/or the thickness of the dielectric layer must decrease accordingly to maintain a similar level of capacitance.
While thinner dielectric layers are generally desirable in the search for improved performance of the capacitive structures used in semiconductor devices, the need for integrity, uniformity and dielectric strength in the dielectric layers can present significant technical barriers to the successful production of such materials. Traditional dielectric materials have included silicon oxides, silicon nitrides, silicon oxynitrides and composites or stacked structures of two or more such materials such as oxide-nitride-oxide (ONO) dielectrics.
These traditional dielectric materials, however, have a relatively low dielectric constant, typically between about 4 and 8, that limits the capacitance that can be obtained with layers being thick enough to maintain sufficient integrity. A number of alternative materials including a range of metal oxides, sometimes called high-k materials, typically having dielectric constants greater than 10, have been investigated and/or utilized to provide improved capacitive performance while allowing the use of thicker material layers. Silicon oxide is commonly used as a standard for comparing the performance of other dielectric materials whereby the thickness of an equivalent silicon oxide layer, i.e., the Toxeq, is calculated according to the Formula III:Toxeq=εox/εinTin  IIIin which εox is the dielectric constant of silicon dioxide, εin is the dielectric constant of the alternative dielectric(s) being used to form the capacitor and Tin is the thickness of the dielectric constant material.
While these alternative high-k dielectric materials such as metal oxides and metal-silicon oxides can be useful as high-performance dielectric materials, it has proven challenging to obtain such layers having sufficient purity and integrity using traditional chemical vapor deposition (CVD) methods employing organometallic precursors, i.e., compounds that contain both metal and carbon, as the source materials for the metal portion of the desired metal oxide because of the likelihood of contamination in the resulting material layers. In particular, capacitors incorporating such dielectric materials tend to suffer from carbon contamination resulting from residues of the organic portion of the organometallic precursor molecule that may degrade the leakage current characteristics of the resulting device.
One prior art solution to the problem of carbon contamination in metal oxide films is to follow the formation of the metal oxide film with an anneal process, generally in combination with a supplemental oxygen source, to "burn-off" the carbon contamination. Such a technique is disclosed in U.S. Pat. No. 6,395,650, the contents of which are incorporated herein by reference, in its entirety, in which the metal oxide film is irradiated with an ultraviolet radiation source such as an ultraviolet laser, an ultraviolet lamp or an ultraviolet plasma radiation source. Although the use of such methods may reduce the level of carbon contamination within the film, these methods also tend to increase the degree of crystallization within the metal oxide film, thereby creating potential alternative leakage paths along the grain boundaries.


Primate embryoid bodies are formed from primate ES cells. The ES cells form clumps. One then removes the clumps, as clumps, and permits incubation under non-adherent conditions. The development of embryoid bodies from primate ES cells is dependent on maintaining the aggregation of cells, as individualized cells will rapidly die.

Undifferentiated primate embryonic stem ("ES") cells can be cultured indefinitely and yet maintain the potential to form differentiated cells of the body. See U.S. Pat. No. 5,843,780; J. Thomson, et al., 282 Science 1145–1147 (1998); and J. Thomson, et al., 38 Biology 133–165 (1998). The disclosure of these publications and of all other publications referred to herein are incorporated by reference as if fully set forth herein.
Primate ES cells thus provide an exciting new model for understanding the differentiation and function of human tissue, and offer new strategies for drug discovery and testing. They also promise new therapies based on the transplantation of ES cell-derived tissues. For example, human and rhesus monkey ES cells injected into immunocompromised mice form benign teratomas with advanced differentiated derivatives representing all three embryonic germ layers. Easily identified differentiated cells in human ES cell teratomas include smooth muscle, striated muscle, bone, cartilage, gut and respiratory epithelium, keratinizing squamous epithelium, hair, neural epithelium, and ganglia.
Human and non-human primate ES cell lines provide a particularly powerful new model for understanding normal human development and thus also for understanding abnormal human development. Because of the potential risk to the resulting child, experimental manipulation of the post-implantation human embryo is ethically unacceptable and as a result functional studies on human embryos are lacking. Consequently, what is known about human development in the early post-implantation period is based almost entirely on static histological sections of a few human embryos and on analogy to experimental embryology studies of the mouse.
However, early mouse and primate development differ significantly. For example, human and mouse embryos differ in the timing of embryonic genome expression, in the formation, structure, and function of the fetal membranes and placenta and in the formation of an embryonic disc instead of an egg cylinder. The earliest events of human development are critically involved in human infertility, pregnancy loss, and birth defects. Primate ES cells offer a new window for understanding these early human developmental events and for understanding the pathogenesis of developmental failures.
Primate ES cells also provide a potentially unlimited source of differentiated, euploid, non-transformed cells for investigators interested in the normal function and pathology of specific differentiated primate cells. Such purified populations of specific ES cell-derived cells will also likely be useful for drug discovery, toxicity screens, and will provide a source of cells for transplantation.
For tissues such as the heart that completely lack a tissue-specific stem cell, primate ES cells will prove even more valuable. Primate ES cells also offer the promise of new transplantation therapies. When disease results from the destruction or dysfunction of a limited number of cell types, such as in Parkinson's disease (dopaminergic neurons), or juvenile onset diabetes mellitus (pancreatic β-islet cells), the replacement of those specific cell types by ES cell derivatives could offer potentially life long treatment.
To accomplish these goals, it is desirable to more efficiently differentiate ES cells to specific lineages. Considerable progress in causing non-primate ES cell differentiation to neural, hematopoietic, and cardiac tissue has been made. See e.g. T. Doetschman, et al., 87 J. Embry. And Exper. Morph. 27–45 (1985); G. Keller, 7 Current Op. In Cell Biol. 862–869 (1995); U.S. Pat. No. 5,914,268. In each of these examples, ES cells were first formed into "embryoid bodies", three-dimensional ES cell aggregates that facilitate subsequent differentiation.
However, analogous experiments on primate ES cells demonstrated that embryoid body formation by conventional murine protocols fail. In such conventional protocols ES cells are dispersed to single cells, and either allowed to aggregate into embryoid bodies under conditions that prevent cell attachment to the substrate, or the ES cells are allowed to grow into embryoid bodies from single cells or clusters suspended in methylcellulose. We have learned that primate ES cells die rapidly when dispersed to single cells if attachment is prevented, so they do not successfully aggregate, and they therefore do not grow out from clones in methylcellulose.
It can therefore be seen that a need exists for improved methods for producing primate embryoid bodies, and differentiated cells derived therefrom.

This patent is subject to a terminal disclaimer.

Method of making embryoid bodies from primate embryonic stem cells


A novel class of compounds that includes HPTS-Cys-MA, and methods of making them are disclosed herein. The class of compounds including HPTS-Cys-MA are useful as fluorescent dyes for analyte detection.

1. Field of the Invention
Novel fluorescent dyes are disclosed for use in analyte detection.
2. Description of the Related Art
Fluorescent dyes, including 8-hydroxypyrene-1,3,6-trislfonic acid (HPTS) and its derivatives, are known and have been used in analyte detection. See e.g., U.S. Pat. Nos. 6,653,141, 6,627,177, 5,512,246, 5,137,833, 6,800,451, 6,794,195, 6,804,544, 6,002,954, 6,319,540, 6,766,183, 5,503,770, and 5,763,238; and co-pending U.S. patent application Ser. Nos. 10/456,895 and 11/296,898; each of which is incorporated herein in its entirety by reference thereto.

Fluorescent dyes for use in glucose sensing


The shot cylinder mechanism is moved from a position for receiving molten metal to an injection position wherein the molten metal is injected into the die cavity of the die casting machine, and vice versa. The shot cylinder mechanism is swung in open space from one position to the other as it is guided by a linkage system having a geometry that takes advantage of the constant speed of the cylinder to give faster, non-linear motion in moving from one position to the next and then at the end of the injection position, the proper force is exerted on the shot cylinder mechanism to provide a seal between the shot sleeve and the opening leading to the die cavity.

The present invention relates to an improved vertical shot mechanism or a die casting machine and more particularly to the mechanism for moving the shot cylinder from a position where the molten metal is introduced into the shot chamber to an injection position where the molten material is injected or shot into the die cavity.
Heretofore, various means have been provided for moving the vertical oriented cylinder shot mechanism from the molten metal receiving position to a shot injection position and vice versa. For example, reference is made to U.S. Pat. No. 4,286,648 issued on Sep. 1, 1981, in which the injection cylinder is moved from the molten metal receiving position to the injection position by the combination of a power cylinder, a link mechanism, and a cam plate which includes a guide slot. The path of the injection or shot cylinder in the U.S. Pat. No. 4,286,648 patent is guided entirely by the cam plate which results in the roller riding within the cam slot. Practical tolerances needed for such designs usually lead to unrestricted "lost" motion which results in vibrating the injection cylinder mechanism which detrimentally agitates the molten metal within the mechanism. Further, although the apparatus of said patent may possibly decrease the interval between the so called teeming of the metal and the starting of the injection as compared to prior apparatus and as alleged in the patent, it is believed that the time interval is not significantly better than prior art apparatus. Improvement in the decrease of such time interval has had a long felt need.
The apparatus of the U.S. Pat. No. 4,286,648 patent also is complicated apparatus requiring substantial column-like structures for supporting a shot cylinder mechanism and also the mechanism for actuating the same.

Vertical shot mechanism for die casting machine


The present invention entails a method and apparatus for automatically glue-bonding scrim to a non-woven fiber mat. The fiber mat and scrim are both conveyed or advanced towards a pair of compression rollers. Prior to reaching the compression rollers, a series of glue guns direct a spray of glue onto one side of either the fiber mat or the scrim. Thereafter, the fiber mat and scrim are fed through the pair of compression rollers that press the scrim and fiber mat together to form a bonded fiber mat-scrim composite. From the compression rollers, the final formed fiber mat-scrim composite is conveyed to a take-up station where the composite is overlapped or wound into a roll.

Fiber mat material is widely used as a cushioning or padding material in a variety of products such as upholstered furniture, and bedding and quilting products. Typically, such fiber mat material comprises unbonded non-woven synthetic fibers and assumes a generally high loft, low to medium density character.
Typically, fiber mats are placed directly into products without any covering or sheathing. In certain situations, the individual fibers from the fiber mat tend to migrate and penetrate the covering of the product itself. This is, of course, undesirable. To counter this problem, it is known to apply a scrim type material to one side of an unbonded non-woven fiber mat. In particular, it is known to stitch the scrim to the fiber mat by simply penetrating the scrim and the fiber mat with a series of needles. In such a needle stitching process, the needles repeatedly pierce the scrim and move down into the fiber mat, after which the needles are retracted. In this process, fiber is pulled from the mat through various needle openings in the scrim and this tends to couple the scrim to the fiber mat. In addition, it is known to stitch scrim to a fiber mat by a conventional stitching technique. This is typically carried out on a Fales stitching machine.
However, these needle stitching processes are not totally satisfactory. First, with either stitching process, the fiber mat is compressed and accordingly the mat looses some of its loft. That is obviously undesirable. Secondly, the scrim is only attached at certain points. This obviously results in the scrim assuming a wrinkled surface about one side of the fiber mat. More importantly, the scrim that is simply needle stitched to the fiber mat and is not firmly attached and is prone to becoming separated from the fiber mat.

Method and apparatus for automatically glue-bonding scrim to a fiber mat


Systems and methods provide a conversational website or native application. The conversational website or native application includes an interface that enables a network device to exchange one or more messages with a bot or a terminal device (operated by a live agent) during a communication session. The interface may include a communication area (e.g., a portion of the screen) and a dynamic content area (e.g., another portion of the screen). The content of a message received from the network device may be used to select dynamic content to display in the dynamic content area. Dynamic updating of content displayed in the dynamic content area occurs continuously as messages are exchanged during the communication session.

Networks, such as the Internet, have become an increasingly important part of our everyday lives. Millions of people now access the Internet on a daily basis to shop for goods and services and obtain information of interest.
The web is built on a very simple, but powerful premise. Much of the material on the web is formatted in a general, uniform format called HTML (Hypertext Markup Language) or the like, and all information requests and responses conform to a similarly standard protocol. When someone accesses a server on the Web, the user's Web browser will send an information request to a Web server. The Web server will respond to the request by transmitting the desired information to the user's computer. There, the user's browser will display the received information on the user's screen.
Some Web services allow users to initiate or join communication sessions with other users. These communication sessions are typically text-only boxes that allow messages to be exchanged.

Bot response generation with dynamically-changing website or native application


A downhole submersible pumping system includes an adapter for use in connecting a first component to a second component within the downhole pumping system. The adapter preferably includes an upstream section configured for connection to the first component and a downstream section configured for connection to the second component. The adapter further includes an articulating joint that permits the angular movement of the first component with respect to the second component.

Submersible pumping systems are often deployed into wells to recover petroleum fluids from subterranean reservoirs. Typically, a submersible pumping system includes a number of components, including an electric motor coupled to one or more high performance pump assemblies. Production tubing is connected to the pump assemblies to deliver the petroleum fluids from the subterranean reservoir to a storage facility on the surface.
The motor is typically an oil-filled, high capacity electric motor that can vary in length from a few feet to nearly one hundred feet, and may be rated up to hundreds of horsepower. Prior art motors often include a fixed stator assembly that surrounds a rotor assembly. The rotor assembly rotates within the stator assembly in response to the sequential application of electric current through different portions of the stator assembly. The motor transfers power to the pump assembly through a common shaft keyed to the rotor. For certain applications, intermediate gearboxes can be used to increase the torque provided by the motor to the pump assembly.
Pump assemblies often employ axially and centrifugally oriented multi-stage turbomachines. Most downhole turbomachines include one or more impeller and diffuser combinations, commonly referred to as "stages." In many designs, each impeller rotates within adjacent stationary diffusers. During use, the rotating impeller imparts kinetic energy to the fluid. A portion of the kinetic energy is converted to pressure as the fluid passes through the downstream diffuser. The impellers are typically keyed to the shaft and rotate in unison.
Often, it is desirable to deploy the pumping system in an offset, deviated, directional, horizontal or other non-vertical well. In these applications, the length and rigidity of the pumping system must be considered as the system is deployed and retracted through curved or angled portions of the well. As the incidence of non-vertical wellbores increases, there is need for a pumping system that can navigate these non-vertical deployments. It is to this and other deficiencies in the prior art that the present invention is directed.


This invention relates to an antenna operable in a multi-mode radio transceiver. One aspect of the present invention, provides a radio antenna having resonant frequencies operable to receive and transmit radio signals in different frequency bands according to two operating protocols.

Personal communication networks are being deployed extensively world-wide using cellular mobile radio systems. Earlier networks, still in operation, use analogue modulation formats for the radio air interface protocol. These analogue networks exhibit the problem of call saturation in high usage areas. To overcome this problem higher capacity air interface protocols using digital modulation format networks have been introduced in tandem, that is an area is covered by both systems.
In the United States and Canada the early standardised analogue network known as AMPS has reached a fairly universal coverage of the populated North American continent. The newer digital networks, however, tend to be deployed in areas of high usage. A result of this is that there are areas of digital network coverage overlaying a universal analogue network coverage. Additionally, different air interface protocol standards of digital networks have been deployed regionally, since different telecommunications operators have developed their own protocols or have developed such protocols in line with national and sometimes international standards authorities, for example, the GSM protocol. Whilst it is reasonable to suppose that handsets operable for different radio communications protocols are similar from the users point of view, it is not possible, in particular, to use a digital mobile radio in an analogue cellular region and vice versa. This stems from the fact that whilst both types of handsets possess antennas, radio front end transmitter, receiver and baseband circuits, they operate on different air interface protocols which operate, inter alia at different radio carrier frequencies.
Therefore it can be seen that each individual personal communications system user will need a dual network service for complete coverage. Consequently the user requires a handset that will not only function throughout the coverage area of the specific subscribed-to digital network, but also have a switched alternative mode to operate on the universal analogue network.
The problem of implementing a dual mode handset has been considered to be surmountable by several different approaches; one solution uses two separate radio transceivers piggybacked and combined at the man-machine interface (keyboard and audio); a second solution uses two separate radio sections piggybacked and combined at the digital signal processing part of the radio transceiver, --applicants have a pending application relating to such a scheme, GB9603316.2. These two above approaches have problems in that both modes of operation transmit via an antenna. If the frequencies of operation are different, as indeed they will need to be, then two types of antenna will be necessary.
For a dual mode terminal perhaps the simplest option for the antenna is to use a separate element for each of the desired bands. This could be in form of one external and one internal antenna, or two internal antennas. Two external antennas would be cumbersome, and unsightly. Such use of two antennas which have separate resonant frequencies of operation is accordingly complicated and unwieldy.
For the case where one external and one internal antenna is used it may be better to use the internal antenna to serve the higher frequency band. This keeps the size of the internal antenna down, thus ensuring that the volume required for the antenna inside the handset is kept to a minimum. For the external antenna a standard extractable monopole could be used, with a helix on the end for when the antenna is retracted. Alternatively, a fixed external antenna could be used. For the internal antenna a bent folded monopole could be employed. However, bent folded monopole elements do not provide sufficient bandwidth; for a typical, efficient bent folded monopole element one night expect a 5-7% 10 dB return loss bandwidth.
A number of dual band helical structures have been investigated at the Helsinki University of Technology, and these were presented at the 1996 IEEE VTC Conference. The helical structures presented are shown in FIG. 1. They consist of: (a) two helical antennas, one within the other; (b) a helical-monopole combination; and (c) a helical antenna combined with a wound monopole. The paper states that the dual frequency operation can be obtained from all three of the structures that are shown. Results for structure (a) state that it was tuned to the frequencies 1740 MHz and 900 MHz, and that 10 dB return loss bandwidths were obtained of 5.2% and 2.2% respectively. The dimensions for the antenna were D.sub.1 =6 mm, lh1-12 mm, N.sub.1 =5, D.sub.2 -3 mm, l.sub.h2 =14 mm, N.sub.2 =5, and 1.sub.s =10 mm. Results for structure (b) state that it was tuned to the frequencies 1750 MHz and 894 MHz, and that 10 dB return loss bandwidths were obtained of 12% and 4.5% respectively. Structure (c) is simply a more compact version of (b), and not surprisingly has a narrower bandwidth. For the upper and lower bands, measured bandwidths of 11% and 2.9% were obtained where the overall structure height was 34 mm. Thus, in summary these antennas provide a bandwidth which is not sufficient for many radio applications, and also does not leave any margin for manufacturing tolerances.
A dual band external antenna is described by Ali et al in `A wide band dual meander sleeve antenna`, IEEE Antennas and Propagation Society International Symposium, 1995, vol.2 p.1124-7, Jun. 18-23, 1995, Newport Beach, Calif., USA, and this is called the wide band dual meander sleeve antenna. This antenna is described as potentially useful as a low profile antenna for a dual mode handset. However, the results presented in the paper are for the case where the experimental antenna is mounted on a large ground plane (90 cm.sup.2).
One possible configuration for a combination of antenna elements could be a monopole used to serve the AMPs radio, and an internal bent folded monopole used to serve the PCS radio. Disadvantages arising from such a configuration are: the SAR performance may be unacceptable; the monopole is susceptible to damage/breakage; and, Isolation may be poor.
A still further option is the use of a single antenna structure which is combined with a dual band matching network, but this is also complicated and unwieldy.


A fastener for a reverse fed panelboard circuit breaker is taught. Briefly stated, a resilently deformable pivoting member is disposed between side barrier fins in a two pole panelboard breaker. A pin at one end of the fastener is placed through a screw hole which is contained in the panelboard and disposed between the side barriers of the panelboard breaker, with the fastener rotatably urged towards the breaker so as to, when fully rotated causes the breaker retention tab to be urged against the panelboard retention hook and also for the fastener to lay against and come in contact with the edge of the panelboard breaker thereby preventing removal of the breaker without first removing the fastener.

It is known that there are three principal components of an electrical distribution panelboard; the main breaker, the branch breakers and the panel bus bars. The main breaker, of course, controls the electrical supply to the panelboard itself and serves as a manual disconnect and an overcurrent device. This is generally required for safety and as part of the electrical code. Some main breakers are bolted to the panel bus bars in order to establish an electrical connection. This is particularly so where high current applications are encountered. However, it is frequently the case that in situations where the main breakers are rated for approximately 125 amperes or less, a plug-on connection is used with the panel bus bars. This plug-on type connection is generally the same as the branch circuit breakers.
However, when a main breaker is connected in a plug-in fashion as described above, it is generally described as a back-fed or reverse-fed breaker. The reason for this is that the breaker's wire terminals receive supply wires rather than serve load wires as do the branch breakers. The plug-on connection referred to above is generally via a spring-loaded jaw terminal that is part of the breaker. This jaw grips the panel bus which thereby effects a physical and electrical connection through spring and friction force alone. As such, plug-on breakers are removed as easily as they are installed, that is, without the use of a tool but rather by simply pulling them off the bus bar.
However, recommended, normal and customary safety practices dictate that the power supply to the panel is disconnected before these reverse fed breakers are removed. Typically the individual removing the breakers must go to a separate location (i.e., a power meter, main panel or the like) in order to remove power from the wires feeding the reverse-fed breaker. As one might expect, these recommendations and procedures are sometimes ignored. The result is that when a back fed or reverse fed main breaker is removed without disconnecting the power supply, the breaker's jaws remain electrically live. Therefore, if the person removing the breaker mistakenly assumes or thinks that a branch breaker has been removed, the individual will be generally unaware of the hazard associated with the live jaw on the breaker.
As a direct result of the above, the National Electrical Code and Underwriters Laboratories, Inc. standards dictate and require that an additional fastener be used to secure back fed circuit breakers and similar devices. The logic behind this is to ensure that an extra step is utilized before the breaker can be removed thereby indicating to the individual that this is a back fed breaker and not merely a branch breaker.
Accordingly, a number of schemes have been tried which attempt to physically fasten the breaker to the panelboard. Generally, these attempts utilize screws, clips and the like which are cumbersome and difficult to install, remove and therefore are themselves sometimes simply ignored. Examples of different fastening devices may be found in, for example, U.S. Pat. No. 4,557,047 "Retainer for Molded Case Circuit Breakers" issued Dec. 10, 1985 to M'Sadoques et. al. There, a screw-in conjunction with a rear mounted retainer clip and plate is utilized. Another example of a fastener may be found in U.S. Pat. No. 4,742,608 "Method of Retaining Molded Case Circuit Breakers" issued May 10, 1988 to M'Sadoques et. al. Again, this breaker utilizes a mounting clip or tab which is fastened by a screw to the breaker. Other fastening attempts or schemes have also encompassed brackets and the like, all of which require fastening by use of a screw or the like.
Accordingly, it would be advantageous to provide a retaining mechanism for a breaker which does not require screws, lugs and the like in order to retain the breaker in the panelboard while still satisfying Underwriters Laboratories and the National Electrical Code.
It is yet another object of the present invention to produce a retaining device which is inexpensive to manufacture.
Still another object is to provide a retaining device which is retrofitable with and usable with existing panelboards, breakers and the like.
Still yet another object of the present invention is to produce a retaining device which is simple and easy to use, and thereby be more likely to be used.
Still another object of the present invention is to produce a fastening device which does not require tools or the like for its installation.
It is still yet another object of the present invention to produce a fastener for fixedly securing a circuit breaker in a panelboard so as to inhibit its removal therefrom, comprising a fastening member having a first and second end, a support block disposed at the first end, the support block having a pin extending therefrom wherein the pin is disposable in an aperture in the panelboard, the pin facilitating pivoting of the fastener with respect to the circuit breaker, a fastener bar disposed at the second end, the fastener bar engageable with a portion of the circuit breaker such that the fastening member prevents removal of the circuit breaker from the panelboard.


A delivery device for delivering stock material into a blast furnace includes a transition channel for the stock material, a chute for delivering the stock material, a first annular body, coaxial to and outside the transition channel, adapted to rotate about a first axis, and a second annular body, coaxial to and outside the first annular body, adapted to translate along the first axis with respect to said first annular body and/or to rotate about the first axis together with said first annular body. When the second body translates along the first axis, at least one fixed rack rotates at least one toothed wheel and a respective shaft about a second axis transversal to the first axis, thus causing a change in the inclination of the chute with respect to the first axis.

Stocking a blast furnace typically occurs by passing stock material through an upper opening, or inlet, of the blast furnace. The stock material generally comes from one or more supply tanks arranged above, and therefore upstream of, the upper opening of the blast furnace.
A delivery device arranged between the outlet of the supply tank and the inlet of the blast furnace is used to obtain a good delivery of the material into the blast furnace. The delivery device is provided with a central supply channel and a chute arranged downstream of the channel to deliver the stock material. The chute is arranged at the inlet of the blast furnace and can be both rotated and tilted.
The inclination of the chute is obtained by means of a tilting mechanism. Known tilting mechanisms are particularly cumbersome. Thus, the overall dimensions of the delivery device disadvantageously are affected by the dimensions of the chute tilting mechanism.
An example of known chute tilting mechanism is disclosed in document KR20030004601A.


A semiconductor system including a semiconductor integrated circuit or a semiconductor chip, and a method of driving the semiconductor system are described. The semiconductor integrated circuit includes a plurality of semiconductor chips, at least one first chip through via suitable for penetrating through the plurality of semiconductor chips and interfacing a source ID code between the plurality of semiconductor chips, a plurality of second chip through vias suitable for penetrating through the plurality of semiconductor chips and interfacing a plurality of chip selection signals between the plurality of semiconductor chips, wherein the semiconductor chip uses one of chip selection signals as an internal chip selection signal in response to a chip ID code by selecting one of a unique ID code for the semiconductor chip and an alternative ID code for a preset semiconductor chip when the semiconductor chip fails.

1. Field
Exemplary implementations of the present invention relate to a semiconductor design technology, and more particularly, to a semiconductor chip, a semiconductor integrated circuit including the semiconductor chip, a semiconductor system including the semiconductor integrated circuit, and a method of driving the semiconductor system.
2. Description of the Related Art
Generally, a packaging technology of a semiconductor integrated circuit has been continuously developed to satisfy a demand for miniaturization of the semiconductor integrated circuit and mounting reliability thereof. Recently, various technologies of a stack package have been developed to satisfy a demand for small-sized and multi-functional electric/electronic products.
The "stack" used in a semiconductor industry refers to vertically stacking at least two semiconductor chips or packages. For example, in the case of a semiconductor memory device, a product having a memory capacity twice or more than a memory capacity which may be implemented during a semiconductor integrated process may be implemented by a stack package. Further, since the stack package may have advantages, such as the increase in memory capacity, the use efficiency of mounting density and mounting area, and the like, a research and development for the stack package has been accelerated.
The stack package may be largely manufactured by a method of stacking individual semiconductor chips and then packaging stacked semiconductor chips at a time and a method of stacking individually packaged semiconductor chips. The individual semiconductor chips of the stack package are electrically connected to each other through a metal wire, a through silicon via (TSV), and the like. In particular, the stack package using the through silicon via has a structure in which the semiconductor chips are physically and electrically connected to each other vertically through the through silicon via formed in the semiconductor chip.
Meanwhile, in the semiconductor integrated circuit having the stack package structure, different chip IDs may be allocated to the stacked semiconductor chips so as to select a desired semiconductor chip among the stacked semiconductor chips. In other words, when a chip selection code is applied to the semiconductor integrated circuit from an external controller in the state in which each chip ID is allocated to the stacked semiconductor chips, a prearranged semiconductor chip may be selected based on a previously allocated chip ID.
FIG. 1 illustrates a configuration of a conventional semiconductor integrated circuit.
The present specification describes, for example, a semiconductor integrated circuit having a quad die package (QDP) in which four semiconductor chips are stacked.
Referring to FIG. 1, a semiconductor integrated circuit includes first to fourth semiconductor chips 10, 20, 30, and 40 which are vertically stacked and electrically connected to each other through first chip through via groups TSV00 and TSV01 and second chip through via groups TSV10, TSV11, TSV12, and TSV13. In this configuration, only the first semiconductor chip 10 is connected to the outside and the second to fourth semiconductor chips 20, 30, and 40 are connected to the outside through the first semiconductor chip 10.
Each of the first to fourth semiconductor chips 10, 20, 30, and 40 includes a unique ID allocation unit, a decoder, a chip selection signal input unit, and first to fourth pads. The unique ID allocation unit 11, 21, and 41 allocates its own unique ID code ID_SLICE<0:1>. The decoder 13, 23, 33, and 43 decodes the unique ID code ID_SLICE<0:1> output from the unique ID allocation unit 11, 21, 31, and 41 to generate chip ID codes DEC_SLICE<0:3>. The chip selection signal input unit 15, 25, 35, and 45 selects any one of the first to fourth chip selection signals CS0#, CS1#, CS2#, and CS3# in response to the chip ID code DEC_SLICE<0:3> and outputs the selected chip selection signal as an internal chip selection signal CS#_SEL. The first to fourth pads PD0, PD1, PD2, and PD3 receive the first to fourth chip selection signals CS0#, CS1#, CS2#, and CS3#, respectively.
In this case, the unique ID allocation unit 11, 21, 31, and 41 outputs source ID codes UP_SLICE<0:1> transferred from the unique ID allocation units of a neighboring semiconductor chip as the unique ID codes ID_SLICE<0:1 and up-counts or down-counts the unique ID codes ID_SLICE<0:1> to be transferred to another neighboring semiconductor chip through the first chip through via groups TSV00 and TSV01. For example, the unique ID allocation unit 11 included in the first semiconductor chip 10 generates the unique ID code ID_SLICE<0:1> of '00' and up-counts the unique ID code ID_SLICE<0:1> to transfer a source ID code UP_SLICE<0:1 of '01' to the unique ID allocation unit 21 of the second semiconductor chip 20 through the first chip through via groups TSV00 and TVS01. The unique ID allocation unit 21 included in the second semiconductor chip 20 generates a unique ID code ID_SLICE<0:1> of '01' corresponding to the source ID code UP_SLICE<0:1> of '01' and up-counts the unique ID code ID_SLICE<0:1> of '01' to generate a source ID code UP_SLICE<0:1> of '10' to be transferred to the unique ID allocation unit 31 of the third semiconductor chip 30. The unique ID allocation unit 31 included in the third semiconductor chip 30 generates a unique ID code ID_SLICE<0:1> of '10' corresponding to the source ID code UP_SLICE<0:1> of '10' and up-counts the unique ID code ID_SLICE<0:1> of '10' to generates a source ID code UP_SLICE<0:1> of '11' to be transferred to the unique ID allocation unit 41 of the fourth semiconductor chip 40. The unique ID allocation unit 41 of the fourth semiconductor chip 40 generates a unique ID code ID_SLICE<0:1> corresponding to the source ID code UP_SLICE<0:1> of '11'. Meanwhile, the unique ID allocation unit 11 included in the first semiconductor chip 10 is designed to generate the unique ID code ID_SLICE<0:1> of a predefined value, for example, '00', as an input terminal of the source ID code UP_SLICE<0:1> floats.
In addition, the decoders 13, 23, 33, and 43 are a known technology, and therefore the detailed description thereof will be omitted.
FIG. 2 illustrates an internal configuration of the chip selection signal input unit 15, 25, 35, and 45.
Referring to FIG. 2, the chip selection signal input units 15, 25, 35, and 45 have the same configuration, and therefore only the chip selection signal input unit 15 included in the first semiconductor chip 10 will be representatively described below.
The chip selection signal input unit 15 includes first to fourth buffer units BUF0, BUF1, BUF2, and BUF3, a chip selection signal transfer unit 15_1 and an internal chip selection signal generation unit 15_3. Each of the first to fourth buffer units BUF0, BUF1, BUF2, and BUF3 is configured to buffer the first to fourth chip selection signals CS0#, CS1#, CS2#, and CS3# input through the first to fourth pads PD0, PD1, PD2, and PD3. The chip selection signal transfer unit 15_1 is configured to selectively transfer output signals of the first to fourth buffer units BUF0, BUF1, BUF2, and BUF3 in response to the chip ID codes DEC_SLICE<0:3>. The internal chip selection signal generation unit 15_3 is configured to logically combine output signals of the chip selection signal 15_1 to generate an internal chip selection signal CS#_SEL.
Herein, the chip selection signal transfer unit 15_1 includes a first path selection unit INV0 and INV1 configured to selectively transfer the output signal of the first buffer unit BUF0 in response to the first code DEC_SLICE<0> among the chip ID codes DEC_SLICE<0:3>, a second path selection unit INV2 and INV3 configured to selectively transfer the output signal of the second buffer unit BUF1 in response to the first and second codes DEC_SLICE<0> and DEC_SLICE<1> among the chip ID codes DEC_SLICE<0:3>, a third path selection unit IN4 and IN5 configured to selectively transfer the output signal of the third buffer unit BUF2 in response to the first and third codes DEC_SLICE<0> and DEC_SLICE<2> among the chip ID codes DEC_SLICE<0:3>, and a fourth path selection unit INV6 and INV7 configured to selectively transfer the output signal of the fourth buffer unit BUF3 in response to the first and fourth codes DEC_SLICE<0> and DEC_SLICE<3> among the chip ID codes DEC_SLICE<0:3>. The first to fourth path selection units INV0 and INV1, INV2 and INV3, INV4 and INV5, and INV6 and INV7 are serially connected to two inverters which are operated in response to the corresponding codes among the chip ID codes DEC_SLICE<0:3>. In this case, the output terminals BUF_CS0#, BUF_CS1#, BUF_CS2#, and BUF_CS3# of the inverters INV0, INV2, INV4, and INV6 of the front stage are connected to each other through second chip through via groups TSV10, TSV11, TSV12, and TSV13. As described above, since only the first to fourth pads PD0, PD1, PD2, and PD3 are connected to the outside, the first to fourth pads PD0, PD1, PD2, and PD3 and the first to fourth buffer units BUF0, BUF1, BUF2, and BUF3 which are included in the second to fourth semiconductor chips 20, 30, and 40 are in a floating state, such that the chip selection signal input units 25, 35, and 45 of the second to fourth semiconductor chips 20, 30, and 40 may be configured to receive the first to fourth chip selection signals BUF_CS0#, BUF_CS1#, BUF_CS2#, and BUF_CS3# buffered in the first semiconductor chip 10 through the second chip through via groups TS10, TSV11, TSV12 and TSV13.
Further, the internal chip selection signal generation unit 15_3 may include an OR gate which performs an OR operation on the output signal of the chip selection signal transfer unit 15_1.
Hereinafter, an operation of the semiconductor integrated circuit having the above-mentioned configuration will be described.
The unique ID allocation unit 11 included in the first semiconductor chip 10 has a floated input terminal to generate the unique ID code ID_SLICE<0:1> having a preset default value. For example, the unique ID allocation unit 11 generates the unique ID code ID_SLICE 0:1> of '00'. Next, the decoder 13 generates the chip ID code DEC_SLICE 0:3> corresponding to the unique ID code ID_SLICE<0:1>. For example, the decoder 13 generates a chip ID code DEC_SLICE<0:3> of '1000' corresponding to the unique ID code ID_SLICE<0:1> of '00'. Therefore, the chip selection signal input unit 15 finally outputs at any one of the first to fourth chip selection signals buffered by the first to fourth buffer units BUF0, BUF1, BUF2, and BUF3 as the internal chip selection signal CS#_SEL in response to the chip ID code DEC_SLICE<0:3>. For example, the chip selection signal input unit 15 selects a first chip selection signal buffered by the first buffer unit BUF0 in response to the chip ID code DEC_SLICE<0:3> of '1000' and determines whether the internal chip selection signal CS#_SEL is activated depending on whether the first chip selection signal CS0# is activated.
Meanwhile the unique ID allocation unit 11 included in the first semiconductor chip 10 outputs the source ID code UP_SLICE<0:1> generated by up-counting or down-counting the unique ID code ID_SLICE<0:1> to the second semiconductor chip 20 through the first chip through via groups TSV00 and TSV01. For example, the unique ID allocation unit 11 up-counts the unique ID code ID_SLICE<0:1> of '00' to generate the source ID code UP_SLICE<0:1> of '01'.
Next, the unique ID allocation unit 21 included in the second semiconductor chip 20 generates the unique ID code ID_SLICE<0:1> corresponding to the source ID code UP_SLICE<0:1> output from the first semiconductor chip 11. For example, the unique ID allocation unit 21 generates the unique ID code ID_SLICE<0:1> of '01'. Next, the decoder 23 generates the chip ID code DEC_SLICE<0:3> corresponding to the unique ID code ID_SLICE<0:1>. For example, the decoder 23 decodes the unique ID code ID_SLICE<0:1> of '01' to generate a chip ID code DEC_SLICE<0:3> of '0100'. Therefore, the chip selection signal input unit 25 finally outputs any one of the first to fourth chip selection signals CS0#, CS1#, CS2#, and CS3# buffered in the first semiconductor chip 10 as the internal chip selection signal CS#_SEL in response to the chip ID code DEC_SLICE<0:3>. For example, the chip selection signal input unit 25 selects the second chip selection signal buffered by the second buffer unit BUF1 in response to the chip ID code DEC_SLICE<0:3> of '0100' and determines whether the internal chip selection signal CS#_SEL is activated depending on whether the second chip selection signal CS1# is activated.
Meanwhile, the unique ID allocation unit 21 included in the second semiconductor chip 20 outputs the source ID code UP_SLICE<0:1> generated by up-counting or down-counting the unique ID code ID_SLICE<0:1> to the third semiconductor chip 30 through the first chip through via groups TSV00 and TSV01. For example, the unique ID allocation unit 21 up-counts the unique ID code ID_SLICE<0:1> of '01' to generate the source ID code UP_SLICE<0:1> of '10'.
Next, the unique ID allocation unit 31 included in the third semiconductor chip 30 generates the unique ID code ID_SLICE 0:1> corresponding to the source ID code UP_SLICE<0:1> output from the second semiconductor chip 21. For example, the unique ID allocation unit 31 generates the unique ID code ID_SLICE<0:1> of '10'. Next, the decoder 33 generates the chip ID code DEC_SLICE 0:3> corresponding to the unique ID code ID_SLICE<0:1>. For example, the decoder 33 decodes the unique ID code ID_SLICE<0:1> of '10' to generate a chip ID code DEC_SLICE<0:3> of '0010'. Therefore, the chip selection signal input unit 35 finally outputs any one of the first to fourth chip selection signals CS0#, CS1#, CS2#, and CS3# buffered in the first semiconductor chip 10 as the internal chip selection signal CS#_SEL in response to the chip ID code DEC_SLICE<0:3>. For example, the chip selection signal input unit 35 selects a third chip selection signal buffered by the third buffer unit BUF2 in response to a chip ID code DEC_SLICE<0:3> of '0010' and determines whether the internal chip selection signal CS#_SEL is activated depending on whether the third chip selection signal CS2# is activated.
Meanwhile, the unique ID allocation unit 31 included in the third semiconductor chip 30 outputs the source ID code UP_SLICE<0:1> generated by up-counting or down-counting the unique ID code ID_SLICE<0:1> to the fourth semiconductor chip 40 through the first chip through via groups TSV00 and TSV01. For example, the unique ID allocation unit 31 up-counts the unique ID code ID_SLICE<0:1> of '10' to generate a source ID code UP_SLICE<0:1> of '11'.
Finally, the unique ID allocation unit 41 included in the fourth semiconductor chip 40 generates the unique ID code ID_SLICE<0:1 corresponding to the source ID code UP_SLICE<0:1> output from the third semiconductor chip 30. For example, the unique ID allocation unit 41 generates a unique ID code ID_SLICE<0:1> of '11'. Next, the decoder 43 generates a chip ID code DEC_SLICE 0:3> corresponding to the unique ID code ID_SLICE<0:1>. For example, the decoder 43 decodes the unique ID code ID_SLICE<0:1> of '11' to generate a chip ID code DEC_SLICE<0:3> of '0001'. Therefore, the chip selection signal input unit 45 finally outputs any one of the first to fourth chip selection signals CS#, CS#1, CS2#, and CS3# buffered in the first semiconductor chip 10 as the internal chip selection signal CS#_SEL in response to the chip ID code DEC_SLICE<0:3>. For example, the chip selection signal input unit 45 selects the fourth chip selection signal buffered by the fourth buffer unit BUF3 in response to the chip ID code DEC_SLICE 0:3> of '0001' and determines whether the internal chip selection signal CS#_SEL is activated depending on whether the fourth chip selection signal CS3# is activated.
The semiconductor integrated circuit having the above-mentioned configuration allocates chip IDs to each semiconductor chip 10, 20, 30, and 40, thereby easily transferring the chip selection signals allocated to each semiconductor chip 10, 20, 30, and 40.
However, when any one of the semiconductor chips 10, 20, 30, and 40 fails, the semiconductor integrated circuit may not use the remaining semiconductor chips. This is because the chip ID code DEC_SLICE<0:3> is fixedly allocated to each semiconductor chip 10, 20, 30, and 40. For example, when the third semiconductor chip 30 or the fourth semiconductor chip 40 fails, the first and second semiconductor chips 10 and 20 may be used as a double die package (DDP), but when the second semiconductor chip 20 fails, the first and second semiconductor chips 10 and 20 may not used as the double die package (DDP).

Semiconductor chip, semiconductor integrated circuit including the semiconductor chip, semiconductor system including the semiconductor integrated circuit and method of driving the semiconductor system


A method for increasing the optical transmission characteristics of zinc sulfide in the visible and infrared portions of electromagnetic spectrum is described. Materials such as metals and, in particular, transition metals are diffused through the zinc sulfide material over a duration of time sufficient to cause the material to turn substantially water clear and substantially colorless.

This invention relates generally to optical elements and more particularly to infrared optical elements having enhanced transparency in the visible, as well as, the infrared spectrums.
As it is known in the art, optical imaging systems generally include one or more externally mounted optical elements which isolate the remainder of the imaging system from an external environment. It is also known in the art that certain applications of these optical elements are on dual mode systems which require transparency in both the infrared as well as the visible portions of the electromagnetic spectrum.
When the portions of the electromagnetic spectrum include long wavelength infrared energy (LWIR) particularly in the 8-12 micron band, the number of materials which also provide suitable transparency in the visible portion of the spectrum are limited. Materials which have theoretical transparency in the infrared 8-12.mu. and the visible are generally alkaline-earth halides, wide bandgap semiconductor materials and diamond. One such material, in particular, is zinc sulfide. As deposited or grown fully dense, polycrystalline ZnS is orange in color having very little transmittance in the visible due to scattering effects. It is known that this orange, optical grade chemically vapor deposited zinc sulfide, which is transparent over the range of about 0.5.mu. to 12.mu., when subjected to a hot isostatic treatment, that is a treatment at an elevated pressure and an elevated temperature, causes the zinc sulfide to become transparent in the visible portion of the electromagnetic spectrum, as well as, the infrared portions of the electromagnetic spectrum.
This treatment, however, has one drawback. The HIPping of the zinc sulfide material causes grain growth in the material. An increase in the grain size of the zinc sulfide provides a concomitant reduction in the mechanical strength properties of the material. That is, although HIPping increases the optical performance of the material, HIPping also reduces the strength of the material. Although such treated zinc sulfide material is suitable for many applications, it would nevertheless be desirable to provide zinc sulfide material which is transparent in both the visible and infrared spectrums while still retaining relatively high mechanical strength properties. Moreover, it would also be desirable to provide other materials having improved optical transparency in the visible and infrared.

Zinc sulfide bodies having improved optical transmittance characteristics and mechanical characteristics


A manufacturing method comprises the steps of changing an identification number of each electronic device 15 into a bar code and adhering it to an electronic component 18, reading the bar code 12a, and writing information of the bar code in a memory of the electronic device 15. All the steps for writing identification numbers are automated so that human errors in setting the identification numbers by an operator can be prevented.

The present invention relates to a manufacturing method of electronic devices having identification numbers used for a cable television (hereinafter referred to as CATV) or the like.
In the CATV system, each CATV receiving set (hereinafter referred to as an electronic device) requires individual service, and therefore, each of such electronic devices must be identified. In order to identify each electronic device, an identification number peculiar to the electronic device is stored in a memory of the electronic device in manufacturing. A conventional manufacturing method of electronic devices having identification numbers will now be described.
The conventional manufacturing method of electronic devices having identification numbers comprises the steps of writing different identification numbers of the respective electronic devices in a management file by the operator, setting the identification numbers written in the management file in an identification number writing device, and writing the set identification numbers in the electronic devices.
However, in the conventional method, writing of the identification numbers is manually conducted by an operator, and consequently, errors inevitably occur in setting the numbers in the identification number writing device.

Manufacturing method of electronic devices having identification numbers

Matsushita Electric Industrial Co., Ltd.


The connection between a plurality of antenna output signals and a plurality of finger units is switched in dependence upon a reception state of each multipath propagation path at each antenna branch to controllably select those finger units to be subjected to RAKE combination. A particular finger unit is excluded from RAKE combination if the reception state does not satisfy a predetermined condition.

This invention relates to a RAKE reception method of receiving a spread spectrum signal in mobile communication.
In recent years, it is attempted to apply a spread spectrum communication system to mobile communication. This is because the spread spectrum communication system is highly tolerant to interference or jamming so as to achieve an excellent reception characteristic even in a multipath environment in which a transmitted signal is reflected and refracted by a variety of terrains or buildings to be received via different propagation paths (hereinafter called multipath propagation paths). Since the spread spectrum communication system uses a high spread frequency, it is possible to distinguish the multipath propagation paths from one another. This allows an application of a RAKE reception system. The RAKE reception system is a technique which provides a path diversity effect. Specifically, the RAKE reception system comprises the steps of separating the multipath propagation paths from one another, estimating propagation path characteristics of the individual paths, compensating reception signals of the individual paths with the propagation path characteristics to produce compensated reception signals, and coherently combining the compensated reception signals. In the RAKE reception system, a portion called a "finger" carries out the estimation of the propagation path characteristic of each individual path and the compensation therefor. For this purpose, the finger comprises a weighting factor estimating portion and a weighting circuit. The finger also includes a correlator for despreading a spread spectrum code (see Reference 1: Andrew J. Viterbi, CDMA/Principles of Spread Spectrum Communication, Addison-Wesley Publishing Company, page 89, 1995).
In case where propagation path delays in the individual multipath propagation paths can be separated from one another by the spread frequency, the RAKE reception system having the path diversity effect is extremely effective. However, if the difference in propagation distance among the multipath propagation paths is small such as in an urban area, path separation may be impossible in dependence upon the spread frequency. In this event, flat fading appears in the reception signals of the individual paths. In order to avoid the deterioration in reception characteristic due to the flat fading, it is effective to utilize a space diversity effect obtained by a plurality of antennas arranged apart from one another. Taking the above into consideration, it is proposed to combine the path diversity effect of the RAKE reception system and the space diversity effect by the plurality of antennas.
For example, Reference 2 (JP-A 8-237171) discloses a method of arranging a plurality of antennas as antenna branches, measuring RAKE reception levels of the individual antenna branches, and selecting a particular one of the antenna branches which has a highest reception level. Instead of switching among the antenna branches, Reference 3 (Higashi et al, "Path/Space Joint Diversity Performance of Coherent Detection RAKE with Interpolation on DS-CDMA", Proceedings of IEICE General Conference, B-410, 1995) and Reference 4 (Karasawa et al, "A Space-Path Hybrid Diversity Scheme for Base-Station Reception in CDMA Mobile Radio Communication Systems", Technical Report of IEICE, SAT93-12, pages 41-47, 1993) propose a system in which all multipath components received by the individual antenna branches are coherently combined so as to achieve a hybrid effect of the path diversity and the space diversity. In Reference 5 (Andoh et al, "Performance of RAKE and Space Diversity using Multi-pilot-block Channel Estimation for DS-CDMA", Proceedings of IEICE General Conference, B-5-13, 1997), the hybrid effect of the space diversity and the path diversity is confirmed by simulation tests.
Comparing the above-mentioned prior art techniques, the technique of coherently combining all multipath components received by the individual antenna branches (References 3, 4, and 5) is superior in reception characteristic over the technique of switching among the antenna branches (Reference 2).
In the above-mentioned prior art techniques, each antenna branch is fixedly connected to a set of the fingers. This structure is disadvantageous in the following respects. In the urban area with many tall buildings, there are an increased number of multipath propagation paths. In case of mobile communication, new propagation paths appear and old ones disappear very frequently so that the number of the propagation paths varies from time to time. Under the influence of shadowing, the reception characteristic of each individual antenna branch varies in a short time. In order to achieve an optimum reception structure, it is not desirable to permanently fix the connection between the antenna branch and the set of the fingers.
FIGS. 1 and 2 show the RAKE reception systems described in References 2 and 3, respectively. In either system, a preselected number of fingers are fixedly connected to each individual antenna branch. Each of the fingers has a correlator, weighting circuit, and a weighting factor estimating portion. In FIG. 1, RAKE combination is performed in a RAKE combiner for each individual antenna branch to produce a combined reception level. As a result of comparison, a particular antenna branch having a high reception level is selected in a switch SW. In FIG. 2, RAKE combination is performed in a single RAKE combiner to collectively combine all finger outputs of the both antenna branches. As far as a set of the fingers are fixedly assigned to each individual antenna branch, a total number of the fingers required in either system is equal to an integral multiple of the number of the branches. This results in an increase in size of the receiver.
In the prior art techniques, the branches or the paths selected for coherent combination are instantaneously switched upon reception of a small number of symbols. Thus, instantaneous variation of a reception signal received by each individual branch or path is excessively followed. Since the number of multipath propagation paths is great in the urban area as described above, the ratio of signal power to noise power (Eb/No) or the ratio of signal power to interference power (Eb/Io) for each path is small. Thus, other components than a desired signal component occupy a considerable part. Even if path selection is carried out in correspondence to a particular reception signal instantaneously exhibiting high correlation, it is not assured that a resultant reception characteristic is improved in average. In particular, the RAKE combination is effective provided that (1) propagation characteristics of the individual paths are statistically independent from one another and (2) each finger processes a proper reception signal.
In the spread spectrum communication system, when the Eb/No ratio or the Eb/Io ratio for each path is decreased at a particular station under the influence of the interference from other stations or the multipath propagation paths of the particular station itself, pseudo peak correlation appears. If the paths selected for RAKE combination are determined with reference to the pseudo correlation peaks, the resultant reception characteristic is undesiredely deteriorated. Therefore, the fingers selected for RAKE combination must be determined in dependence upon the characteristics of the reception signals. In particular, the paths selected for RAKE combination must be determined so that the average reception characteristic is improved. Since the multipath variation or the variation of the reception signal in each individual antenna branch is in situ probabilistic, high correlation instantaneously obtained does not assure that a path or a branch which is proper in average is caught. In order to avoid any improper path from being caught due to instantaneous variation, it is necessary to incorporate a mechanism for protecting synchronization.

Rake reception method for a spread spectrum signal


Systems, methods, and computer readable media are provided for automating the process of provisioning and maintaining Access Point Names (“APNs”) for use in digital networks, such as GPRS networks. A plurality of network elements including but not limited to GGSN tables, router tables, firewall systems, VPN tunnels, and Home Location Registry (“HLR”) tables can be provisioned and maintained via a centralized system. The invention integrates centralized logging of provisioning, maintenance, and access events, as well as acknowledgement from provisioned network elements, for enhanced security, reporting, and troubleshooting. The invention thus ensures accuracy and reduces operational costs of integrating mobile communications systems with digital networks.

The number of subscribers of mobile communications services has been growing explosively in the past decade. As the popularity of mobile devices expands, the underlying technology that enables mobile communications has also been evolving. Mobile devices evolved from analog transmissions associated with the first mobile phones to digital transmissions presently used by a large variety of mobile communications devices. The big boom in mobile communications can be traced back to the early 1980's when the prevailing technology was Analog Mobile Phone Service ("AMPS"), also known as first generation ("1G"). As time progressed, mobile communications technology took a leap from analog to digital cellar technology, with the emergence two competing technologies: Time Division Multiple Access ("TDMA") and Code Division Multiple Access ("CDMA"). With digital transmissions, more communications can be accommodated in the same amount of radio frequency spectrum. As a result, digital technologies, such as TDMA and CDMA, lay the groundwork for services beyond simple voice telephone calls, and enable data services, e.g., Internet access, text messaging, picture sharing, and so forth to flourish.
The use of digital networks by mobile commmunications devices involves a wide variety of technologies. Data may be converted to a variety of different formats as it is transmitted to its ultimate destination. For example, the Global System for Mobile Communications ("GSM") is presently a popular standard for mobile communications. GSM differs significantly from its predecessors in that both signalling and speech channels are digital, which means that it is seen as a second generation ("2G") mobile device system. Data communication was built into the GSM standard from early on. GSM is an open standard which is currently developed by the 3rd Generation Partnership Project ("3GPP").
Packet data capabilities were added to the GSM standard in 1997 by means of General Packet Radio Service ("GPRS"). Higher speed data transmission have also been introduced with Enhanced Data rates for GSM Evolution ("EDGE") in the 1999 version of the standard. GPRS is a mobile data service available to users of GSM mobile devices. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile communications. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network.
GPRS is different from the older Circuit Switched Data ("CSD") connection included in GSM standards releases before 1997. In the older system, a data connection established a circuit, and reserved the full bandwidth of that circuit during the lifetime of the connection. GPRS is packet-switched, which means that multiple users share the same transmission channel, only transmitting when they have data to send. Web browsing, receiving e-mails as they arrive, and instant messaging are examples of uses that require intermittent data transfers, which benefit from sharing the available bandwidth.
Regardless of the transmission protocols that are used by a particular mobile device, modern transmissions, whether voice, data, or otherwise, will likely travel across a digital network for at least some portion of their voyage to a final destination. Modem mobile communications systems allow data from mobile devices to be transmitted across digital networks such as the Internet. However, any data transmitted across a digital network must be properly packaged and formatted, and sent via digital equipment that is appropriately provisioned. The use of digital networks to transmit data generally involves placing the data, e.g., data originating from a mobile device, onto a digital network. The data is then sent across the digital network to its destination, and finally retrieved from the digital network for consumption by the recipient.
For example, consider a transmission made by a mobile phone. A signal is transmitted from the mobile phone to a receiving antenna. The data represented by the signal may be transmitted from the receiving antenna to a centralized location. The data may then be converted to a format that is optimized for transmission across digital networks. It is packaged so that the digital network will deliver it to the correct location. Assuming the various network elements such as routers, firewall systems, VPN tunnels, and so forth are correctly provisioned, the data then makes its way across the digital network to its destination. Finally, the data sent in the original transmission is reassembled in a useful format for consumption by a recipient.
Sending data across digital networks in this fashion requires a number of properly provisioned elements. When placed on a digital network, data is routed to an Access Point Name ("APN"), e.g. "UPS.com" corresponding to a specific destination, such as the servers controlled by the United Parcel Service ("UPS"). In order to successfully travel to its destination, Gateway GPRS Support Node ("GGSN") tables, Fixed End System router tables, firewall systems, VPN tunnels, and any number of other elements as required by the particular digital network need to be properly provisioned.
Too often, one or more of the network elements may be improperly provisioned, especially when provisioning elements for a new customer for the first time. This may cause one or more failed transmissions, a lag in the time it takes to provision a network for communications, and high provisioning costs as personnel work to troubleshoot and resolve the transmission problem. Decentralized maintenance and updates to such network elements may cause additional delay in troubleshooting buggy or failed connections.
Moreover, wide access to the various network elements by personnel of a mobile communications company presents a security risk, in that access to elements may cause valuable data to be misappropriated. Mistaken, malicious or otherwise inappropriate disabling of elements, as well as misappropriation of sensitive information such as information on how to connect to a private company's servers, is a real security threat that should be taken seriously. Furthermore, it is difficult in present, decentralized network provisioning systems to gather and synthesize information from the various network elements, which is increasingly important for security purposes as well as regulatory compliance and automated troubleshooting technologies.
In light of the above described state of the mobile communications industry, a solution is needed that facilitates provisioning and maintenance of access point names and associated data for digital transmissions, and facilitates centralized information storage and access control.

Automated provisioning, maintenance, and information logging of custom access point names in packet-based mobile cellular networks


A method of controlling a flow rate of inerting gas introduced into a vented aircraft fuel tank, the method comprising: monitoring changes in a quantity of a fuel in the aircraft fuel tank; monitoring changes in the ambient air pressure external to the aircraft fuel tank; and actively controlling a flow rate of inerting gas, {dot over (m)}(I), introduced into the aircraft fuel tank based upon changes in the quantity of fuel in the fuel tank and changes in the ambient air pressure, p. Also, an aircraft including a vented fuel tank, a supply of inerting gas for rendering inert the fuel tank ullage, and a controller for performing the method.

Following in-service incidents of aircraft fuel tank explosions, new regulations to achieve flammability reduction in fuel tanks have been introduced for new commercial aircraft.
The relevant FAA Regulation states: "A fuel tank is considered inert when the bulk average oxygen concentration within each compartment of the tank is 12 percent or less from sea level up to 10,000 feet altitude, then linearly increasing from 12 percent at 10,000 feet to 14.5 percent at 40,000 feet altitude, and extrapolated linearly above that altitude."
Typically this is achieved by continuously adding Nitrogen to the fuel tank ullage during operation and keeping the Ullage Gas Oxygen Fraction (UGOF) below 11%. Currently, one solution is to use Air Separation Modules (ASMs) to molecularly separate the Nitrogen from the Oxygen in air, either obtained as engine bleed air or compressed external air.
On future aircraft it is proposed to use fuel cell technology to provide the auxiliary power for such functions as ground operations, ground propulsion and emergency in-flight power. As a by-product of this technology where Hydrogen is catalytically reacted with Oxygen (supplied from the ambient air) to produce electric power, Oxygen Depleted Air (ODA) is produced where the Oxygen concentration is typically <10.5%. This air is also very humid (approximately 100%) and hot, so it needs to be processed to reduce both its humidity and temperature before it can be used to inert the fuel tanks.
Reducing the temperature and humidity is a known technology however it consumes aircraft resources, in particular creating a high demand when other systems are also at a high demand, typically on aircraft descent into hot destinations.


A two-speed transmission is provided. The transmission comprises a planetary gear train (8) having a sun gear, a fixed annular gear (8b), at least one planet gear (8c) and a planet carrier (8d). A dual clutch (10) is disposed between the planetary gear train and a prime mover which outputs rotational movement. The dual clutch is configured to be driven into a first clutching mode in which it kinematically couples the sun gear with the prime mover, and a second clutching mode in which it kinematically couples the planet carrier with the prime mover. And an actuator is configured to selectively drive the dual clutch into one of its first and second clutching modes. An electric vehicle comprises the two-speed transmission.

The present invention relates to an improved two-speed transmission, in particular for an electric vehicle, which provides two speed ratios with a simple configuration. The present invention also relates to an electric vehicle comprising such a two-speed transmission.
Electric vehicles generally use at least one electric motor for propulsion. Output rotation and torque of the electric motor are transmitted to the wheels of the vehicle via a transmission.
For example, U.S. Pat. No. 6,513,401B2 discloses a transmission unit for axles of vehicles with electric drive, the transmission unit comprising a drive gear, a driven gear, and an intermediate idler gear meshing with both the drive gear and the driven gear. The speed ratio of the transmission unit can be varied by replacing the drive gear and the driven gear and displacing the axis of rotation of the idler gear. However, once the drive gear and the driven gear are set, the transmission unit can provide only a fixed speed ratio.
It is known that an electric motor has a desired speed range in which the electric motor operates in a high efficiency region. The operation efficiency of the electric motor decreases when the speed of the electric motor falls out of this desired speed range. For an electric vehicle having a transmission with a single or fixed speed ratio, as that disclosed in U.S. Pat. No. 6,513,401B2, the electric motor has to operate at a low speed with a low efficiency in some conditions, especially when the running speed of the vehicle is low.
In order to increase the operation efficiency of the electric motor by operating it in the high efficiency region, a transmission which provides more than one speed ratio could be adopted. As an example, CN2875938Y discloses a two-speed automatic transmission for electric vehicles, the transmission comprising two gear pairs for providing different speed ratios, an output shaft which is able to be selectively coupled with either of the two gear pairs, and a splined hub fixed to the output shaft and configured to be displaced by means of a lever. When the vehicle runs at a low speed, the transmission is switched automatically to provide a higher speed ratio so that the electric motor operates at a higher speed, which results in higher efficiency of the electric motor.
However, a transmission with more than one speed ratio generally has a complex configuration. For example, two gear pairs are used in the automatic transmission disclosed in CN2875938Y. Such a transmission may be expensive or have a large size.
It is thus highly desirable to have a transmission which can provide more than one speed ratio with a simple configuration.

Two-speed transmission and electric vehicle


Drill bits comprise a plurality of steel cutting teeth each having a crest positioned at a tip portion of each tooth, a first flank surface extending from the crest to the cone, a second flank surface opposite the first flank surface and extending from the crest to the cone, and edge surfaces extending from the crest to the cone and interposed between the first and second flank surfaces. Each cutting tooth includes corners that extend from the crest to the cone that are defined by the interface between the first and second flank surfaces and the edge surfaces. A wear resistant surface is positioned on selective tooth surfaces comprising at least the crest and a portion of one or more of the corners. The wear surface is not disposed on at least a surface portion of one of the first and second flank surfaces and the edge surfaces.

Rock bits used for drilling oil wells and the like commonly have a steel body that is connected at the bottom of a drill string. Steel cutter cones are mounted on the body for rotation and engagement with the bottom of a hole being drilled to crush, gouge, and scrape rock for drilling the well. One important type of rock bit, referred to as a "milled tooth" bit, has roughly trapezoidal teeth protruding from the surface of the cone for engaging the rock.
Conventional milled teeth are made from steel, and are "hardfaced" for the purpose of providing an improved level of wear protection. Such milled teeth can be completely hardfaced, or be selectively hardfaced to provide a desired self-sharpening effect during drill bit operation. While conventional completely hardfaced teeth are known to offer an adequate level of protection to the underlying steel tooth during the drilling operation, the placement of hardfacing over the entire tooth increases the effective area of the tooth is theorized to have a limiting effect on the ROP.
Conventional self-sharpening teeth are specifically designed having hardfacing disposed along strategic surface areas of the teeth to produce a preferential wearing of the nonhardfaced surfaces. While this combination of wear protected and preferential wearing surfaces produces a sharpened structure known to improve ROP, it is known that some of the nonhardfaced surfaces can leave the teeth vulnerable to erosion cracking, which can eventually cause the teeth to break. Such breakage can have a detrimental impact on achieving the desired ROP.
The term "hardfaced" is understood in industry to refer to the process of applying a carbide-containing steel material (i.e., conventional hardmetal) to the underlying steel substrate by welding process, as is better described below. Thus, the terms "hardfaced layer" or "hardfacing" are understood as referring to the layer of conventional hardmetal that is welded onto the underlying steel substrate.
Conventional hardmetal materials used to provide wear resistance to the underlying steel substrate usually comprise pellets or particles of cemented tungsten carbide (WC—Co) and/or cast carbide particles that are embedded or suspended within a steel matrix. The carbide materials are used to impart properties of wear resistance and fracture resistance to the steel matrix. Conventional hardmetal materials useful for forming a hardfaced layer on bits may also include one or more alloys to provide one or more certain desired physical properties. As mentioned above, the hardfaced layer is bonded or applied to the underlying steel teeth by a welding process.
The hardfaced layer is conventionally applied onto the milled teeth by oxyacetylene or atomic hydrogen welding. The hardfacing process makes use of a welding "rod" or stick that is formed of a tube of mild steel sheet enclosing a filler which is made up of primarily carbide particles. The filler may also include deoxidizer for the steel, flux and a resin binder. The relatively wear resistant filler material is typically applied to the underlying steel tooth surface, and the underlying tooth surface is thus hardfaced, by melting an end of the rod on the face of the tooth. The steel tube melts to weld to the steel tooth and provide the matrix for the carbide particles in the tube. The deoxidizer alloys with the mild steel of the tube.
While this hardfacing process is effective for providing a good bond between the steel substrate and the conventional hardmetal material, it is a relatively crude process that is known to adversely impact the performance properties of the hardfaced layer. The hardfacing welding process itself generates certain welding byproducts that can and does enter the applied material to produce an inconsistent material microstructure. For example, the welding process is known to introduce oxide inclusions and eta-phases into the applied material, which function to disrupt the desired material microstructure. Such disruptions or inconsistencies in the material microstructure are known to cause premature chipping, flaking, fracturing, and ultimately failure of the hardfaced layer. Additionally, the welding process and associated thermal impact of the same can cause cracks to develop in the material microstructure, which can also cause premature chipping, flaking, fracturing, and ultimately failure of the hardfaced layer.
Additionally, the hardfacing process of welding the carbide-containing steel material onto the underlying substrate makes it difficult to provide a hardfaced layer having a consistent coating thickness, which ultimately governs the rate of wear loss for the steel material, and the related service life of bit.
Example conventional hardmetal materials, useful for forming a conventional hardfaced layer, typically comprise in the range of from about 30 to 40 percent by weight steel, and include carbide pellets and/or particles having a particle size in the range from about 200 to 1,000 micrometers. Examples of conventional materials used for forming hardfaced layers can be found in U.S. Pat. Nos. 4,944,774; 5,663,512; and 5,921,330. The combination of relatively high steel content and large carbide particle size for such conventional hardmetal materials dictate that the mean spacing between the carbide pellets within the steel matrix be relatively large, e.g., greater than about 10 micrometers. It is believed that this relatively large mean spacing of carbide particles within the conventional hardmetal material causes preferential wear of the steel matrix that is known to lead to uprooting and removal of the carbide particles. Such wear loss is known to occur along the milled tooth tip at high stress locations during drilling and functions to accelerate loss of the hardfacing, which is a predominant failure mechanism for hardfaced bit surfaces, thereby limiting the service life of such bits.
It is, therefore, desirable that a milled tooth be constructed in a manner providing a desired degree of wear resistance against erosion, while at the same time providing improved ROP when compared to conventional completely hardfaced milled teeth and conventional self-sharpening milled teeth. It is desired that such milled tooth be capable of providing a self-sharpening feature. It is desired that the milled teeth be constructed having a wear and fracture resistant material alternative to conventional hardfacing that avoids the undesired effects of hardfacing, e.g., that avoids the undesired impact on the material microstructure due to the thermal effect and introduction of unwanted byproducts inherent in the welding process, that can adversely impact drill bit surface performance properties. It is desired that such alternative wear and fracture resistant material be designed and/or applied onto the surface of a rock bit in such a manner as to provide improved properties of dimensional consistency and accuracy, e.g., a substantially consistent wear resistant surface thickness, when compared to conventional hardfaced materials. It is also desired that such wear and fracture resistant material be engineered in such a manner as to avoid the problem of preferential wear loss that is inherent to conventional hardmetal materials.

Drill bit cutting elements with selectively positioned wear resistant surface


An optically active compound represented by formula (I): ##STR1## wherein R.sup.1 represents an alkyl group having from 3 to 9 carbon atoms; R.sup.2 represents an alkyl group having from 3 to 7 carbon atoms; m and n each represent 1 or 2 provided that they do not simultaneously represent 1; and C.sup.*1 and C.sup.*2, both represent an optically active carbon atom, and a liquid crystal composition containing the same are disclosed. The compound exhibits chiral nematic and smectic phases and are excellent as a chiral dopant for ferroelectric liquid crystal compositions or nematic liquid crystal compositions.

Liquid crystal displays have been used in various embodiments such as watches and electronic calculators because of their thinness, lightness, and low power driving properties. With the advancement of integrated circuits (IC), liquid crystal displays have been increasing the display size and extending their use in computers, liquid crystal TV sets, etc. in place of conventional cathode-ray tubes.
However, nematic liquid crystals which have conventionally been used have a slow response as needing a switching time of from 10 to 50 milliseconds and also undergo a reduction in display contrast with increases in number of pixels and in display area.
In the state-of-the-art liquid crystal displays, the above-described disadvantages are coped with by providing a thin film transistor (TFT) on each pixel to achieve so-called active matrix driving or by increasing the angle of twist of liquid crystal molecules sandwiched between a pair of substrates to 220.degree. to 270.degree. (called super-twisted nematic mode: STN).
Mounting of TFT according to the former means not only entails very high cost but has a poor yield, resulting in an increased production cost. Cost reduction by introducing a large-scaled production line having been studied, there is a limit due to essential involvement of many production steps. Further, ever since the appearance of high-definition televisions (HDTV), there has been an increasing demand of liquid crystal displays making a high-density display. In nature of TFT and nematic liquid crystals, it is nevertheless considered very difficult to increase display density.
Although the STN mode exhibits an increased contrast ratio, it has a longer response time as long as 100 to 200 milliseconds and is thus limited in its application.
On the other hand, ferroelectric liquid crystals which were proposed by N. A. Clark, et al. as surface-stabilized ferroelectric liquid crystal devices (SSFLD) (refer to N.A. Clark, et al., Appl. Phys. Lett., Vol. 36, p. 899 (1980) have been attracting attention for their fast response reaching about a thousand times that of nematic liquid crystals.
However, such a fast response time is a result obtained in a high temperature range, and the response time obtained around room temperature is impractically as long as several tens of microseconds. Besides, there remains an unsolved problem in molecular orientation. Therefore, ferroelectric liquid crystal display elements have not yet been put to practical use. In particular, the molecular orientation of ferroelectric liquid crystals proved more complicated than thought by Clark, et al. That is, the director of liquid crystal molecules is apt to be twisted in a layer, with which a high contrast ratio cannot be achieved. Further, the layers have been believed to be aligned upright and perpendicular to the upper and lower substrates (bookshelf structure) but, in fact, were found to have a bent structure (chevron structure). As a result, zigzag defects develop to reduce a contrast ratio.
It is known that a response time of ferroelectric liquid crystals is dependent on spontaneous polarization, which develops depending on the dipole moment in the direction perpendicular to the long axis of the molecule, chirality and the orientation of the dipole, rotational viscosity, and intensity of the applied electric field. However, there is a limit of voltage which can be practically derived from an IC used in combination, and a compound having a low viscosity and exhibiting high spontaneous polarization has not been discovered. From these and other reasons, the response time of ferroelectric liquid crystals has not yet been satisfactorily improved.
In general, ferroelectric liquid crystal materials are prepared by adding an optically active compound called a chiral dopant to an achiral base liquid crystal composition showing a smectic C phase (S.sub.c phase). In many cases, phenylpyrimidine type liquid crystal compounds having advantageous viscosity properties are utilized as an achiral base. In actual use, however, properties of the resulting ferroelectric liquid crystal composition, such as viscosity and response time, greatly vary depending on the properties of optically active compounds added thereto.
Further, in order to obtain satisfactory orientation, ferroelectric liquid crystal compositions are demanded to have a smectic A phase (S.sub.A phase) and desirably a nematic phase in which orientation can be effected with relative ease in a higher temperature range.
As containing an optically active compound as mentioned above, a ferroelectric liquid crystal composition in its nematic phase shows a chiral nematic phase (N.sup.* phase) in which a helical structure is induced. If the helical pitch in the N.sup.* phase has temperature dependence, orientation would be difficult. Accordingly, the optically active compound to be added is required not only to provide a liquid crystal composition having the properties demanded as a ferroelectric liquid crystal but also to induce a chiral nematic phase whose helical pitch is less dependent on temperature.
An optically active compound is also used as a chiral dopant for nematic liquid crystal materials for use in nematic liquid crystal displays. In this case, an optically active compound is needed for preventing occurrence of so-called reverse domains in which liquid crystal molecules are twisted to an opposite direction and also for stably maintaining the angle of twist of molecules in the cell. Of the properties demanded for a chiral dopant for a nematic phase, a helical twisting power (HTP=1/concentration by weight.times.helical pitch) is the most important. A chiral dopant with a larger HTP value will be effective in a smaller amount, thus minimizing impairment of the characteristics inherent to host nematic liquid crystal mixtures.
Further, reduction of temperature dependence of a helical pitch in N.sup.* phase is an important factor for a chiral dopant to be added to nematic liquid crystals used in twisted nematic (TN) mode and super twisted nematic (STN) mode display elements. For example, if a chiral dopant shows high positive dependence on temperature (i.e., the pitch is broadened with an increase in temperature), it must be used in combination with a chiral dopant having an opposite tendency to offset the temperature dependence, which makes the chiral dopant mixing system complicated.
The chiral dopant currently used for nematic liquid crystals comprises a mixture of several kinds of optically active compounds for the purpose of controlling a helical pitch in the N.sup.* phase and reducing the temperature dependence of the helical pitch. Not a few of the known optically active compounds exhibit no liquid crystal properties and, when added to a nematic liquid crystal, cause a drop of the nematic-isotropic phase transition temperature.

Optically active compound and liquid crystal composition containing the same


A new and distinct Euryops cultivar named ‘ATN CS5’ is disclosed, characterized by a compact plant habit, bright green foliage, yellow ray and disc florets and continuous flowering.

The new cultivar 'ATN CS5' was discovered as a whole plant mutation. The new cultivar was discovered as a single plant by Lucilene Anatriello in February 2004 in a cultivated area of São José do Rio Preto, Brazil. 'ATN CS5' was discovered growing in a field of Euryops 'Athena Sun'. The exact parents are unknown.
Asexual reproduction of the new cultivar 'ATN CS5' by vegetative cuttings was performed in São José do Rio Preto, Brazil, and has shown that the unique features of this new cultivar are stable and reproduced true to type on successive generations.