The described technology is generally directed towards proactive content placement for low latency mobile access. Digital content requested by a mobile device can be sent to network nodes proactively, so that the network nodes have the digital content before it is requested by the mobile device. Mobile device travel predictions can be made to predict future locations of the mobile device. The future locations can be used to determine network nodes for proactive digital content delivery. The digital content for delivery to a network node can also be predicted based on current digital content in use at the mobile device and estimated arrival times of the mobile device into service areas of next network nodes.

5G wireless technologies will improve the performance and throughput of wireless networks. These wireless network enhancements will enable a new generation of mobile services characterized by low latencies, very high bandwidth, spectrum efficiency, operations automation, and the like.
Enhancements associated with 5G radio access network (RAN) technologies create challenges and opportunities for other systems involved in delivery of end-to-end service. If other systems do not also step up their performance, then the benefits of 5G RAN technologies will hampered.
For example, augmented reality (AR) and virtual reality (VR) technologies are expected to benefit from the low latency and high throughput associated with 5G technologies. AR and VR have promising applications in a variety of areas such as games, advertising, training, education, field-work, etc. Some of these applications will require delivery of digital content to mobile user equipment (UE) devices. In such use cases, an entire end-to-end service may have demands to deliver digital content to a mobile UE at or near the speeds achievable via the 5G RAN.
The above-described background is merely intended to provide a contextual overview of some current issues, and is not intended to be exhaustive. Other contextual information may become further apparent upon review of the following detailed description.

Proactive content placement for low latency mobile access


Group III-nitride quaternary and pentenary material systems and methods are disclosed for use in semiconductor structures, including laser diodes, transistors, and photodetectors, which reduce or eliminate phase separation and provide increased emission efficiency. In an exemplary embodiment the semiconductor structure includes a first ternary, quaternary or pentenary material layer using BInGaAlN material system of a first conduction type formed substantially without phase separation, and a quaternary or pentenary material active layer using BInGaAlN material system substantially without phase separation, and a third ternary, quaternary or pentenary material layer using BInGaAlN material system of an opposite conduction type formed substantially without phase separation.

The development of the blue laser light source has heralded the next generation of high density optical devices, including disc memories, DVDs, and so on. FIG. 1 shows a cross sectional illustration of a prior art semiconductor laser device. (S. Nakamura, MRS BULLETIN, Vol. 23, No. 5, pp. 37-43, 1998.) On a sapphire substrate 5, a gallium nitride (GaN) buffer layer 10 is formed, followed by an n-type GaN layer 15, and a 0.1 μm thick silicon dioxide (SiO2) layer 20 which is patterned to form 4 μm wide stripe windows 25 with a periodicity of 12 μm in the GaN<1-100> direction. Thereafter, an n-type GaN layer 30, an n-type indium gallium nitride (In0.1Ga0.9N) layer 35, an n-type aluminum gallium nitride (Al0.14Ga0.86 N)/GaN MD-SLS (Modulation Doped Strained-Layer Superlattices) cladding layer 40, and an n-type GaN cladding layer 45 are formed. Next, an In0.02Ga0.98N/In0.15 Ga0.85N MQW (Multiple Quantum Well) active layer 50 is formed followed by a p-type Al0.2Ga0.8N cladding layer 55, a p-type GaN cladding layer 60, a p-type Al0.14 Ga0.86N/GaN MD-SLS cladding layer 65, and a p-type GaN cladding layer 70. A ridge stripe structure is formed in the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 55 to confine the optical field which propagates in the ridge waveguide structure in the lateral direction. Electrodes are formed on the p-type GaN cladding layer 70 and n-type GaN cladding layer 30 to provide current injection.
In the structure shown in FIG. 1, the n-type GaN cladding layer 45 and the p-type GaN 60 cladding layer are light-guiding layers. The n-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 40 and the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 65 act as cladding layers for confinement of the carriers and the light emitted from the active region of the InGaN MQW layer 50. The n-type In0.1Ga0.9N layer 35 serves as a buffer layer for the thick AlGaN film growth to prevent cracking.
By using the structure shown in FIG. 1, carriers are injected into the InGaN MQW active layer 50 through the electrodes, leading to emission of light in the wavelength region of 400 nm. The optical field is confined in the active layer in the lateral direction due to the ridge waveguide structure formed in the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 65 because the effective refractive index under the ridge stripe region is larger than that outside the ridge stripe region. On the other hand, the optical field is confined in the active layer in the transverse direction by the n-type GaN cladding layer 45, the n-type Al0.14Ga0.86N/GaN MD-SLS cladding layers 40, the p-type GaN cladding layer 60, and the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 55 because the refractive index of the of the active layer is larger than that of the n-type GaN cladding layer 45 and the p-type GaN cladding layer 60, the n-type Al0.14Ga0.86N/GaN MD-SLS layer 40, and the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 60. Therefore, fundamental transverse mode operation is obtained.
However, for the structure shown in FIG. 1, it is difficult to reduce the defect density to the order of less than 108 cm−2, because the lattice constants of AlGaN, InGaN, and GaN differ sufficiently different from each other that defects are generated in the structure as a way to release the strain energy whenever the total thickness of the n-type In0.1Ga0.9N layer 35, the In0.02Ga0.98N/In0.15Ga0.85N MQW active layer 50, the n-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 40, the p-type Al0.14Ga0.86N/GaN MD-SLS cladding layer 65, and the p-type Al0.2Ga0.8N cladding layer 55 exceeds the critical thickness. The defects result from phase separation and act as absorption centers for the lasing light, causing decreased light emission efficiency and increased threshold current. The result is that the operating current becomes large, which in turn causes reliability to suffer.
Moreover, the ternary alloy system of InGaN is used as an active layer in the structure shown in FIG. 1. In this case, the band gap energy changes from 1.9 eV for InN to 3.5 eV for GaN. Therefore, ultraviolet light which has an energy level higher than 3.5 eV cannot be obtained by using an InGaN active layer. This presents difficulties, since ultraviolet light is attractive as a light source for the optical pick up device in, for example, higher density optical disc memory systems and other devices.
To better understand the defects which result from phase separation in conventional ternary materials systems, the mismatch of lattice constants between InN, GaN, and AlN must be understood. The lattice mismatch between InN and GaN, between InN and AlN, and between GaN and AlN, are 11.3%, 13.9%, and 2.3%, respectively. Therefore, an internal strain energy accumulates in an InGaAlN layer, even if the equivalent lattice constant is the same as that of the substrate due to the fact that equivalent bond lengths are different from each other between InN, GaN, and AlN. In order to reduce the internal strain energy, there is a compositional range which phase separates in the InGaAlN lattice mismatched material system, where In atoms, Ga atoms, and Al atoms are inhomogeneously distributed in the layer. The result of phase separation is that In atoms, Ga atoms, and Al atoms in the InGaAlN layers are not distributed uniformly according to the atomic mole fraction in each constituent layer. In turn, this means the band gap energy distribution of any layer which includes phase separation also becomes inhomogeneous. The band gap region of the phase separated portion acts disproportionately as an optical absorption center or causes optical scattering for the waveguided light. As noted above, a typical prior art solution to these problems has been to increase drive current, thus reducing the life of the semiconductor device.
As a result, there has been a long felt need for a semiconductor structure which minimizes lattice defects due to phase separation and can be used, for example, as a laser diode which emits blue or UV light at high efficiency, and for other semiconductor structures such as transistors.

This patent is subject to a terminal disclaimer.

Semiconductor structures using a group III-nitride material system with reduced phase separation and method of fabrication

Matsushita Electric Industrial Co., Ltd.


In one example in accordance with the present disclosure, a media lifting device is described. The media lifting device includes a media lifting strip to sit on a media transport belt of a printing system. The media lifting strip is to raise a lateral edge of incoming media. That lateral edge of incoming media is a portion of the incoming media that is parallel to a media travel direction. The media lifting device also includes a clamp to affix the media lifting strip to the printing system.

Printing systems are used for precisely, and rapidly, dispensing small quantities of fluid, such as ink, onto media, such as paper. Such printing devices come in many forms. For example, a printing system may include a media transport belt that moves media underneath a printing device which deposits a print agent onto the media.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.


A system for managing mobile electronic communications devices includes a user directory database configured to hold authentication data associated with at least one user, an authentication authority communicatively connected to the user directory database, an administration server configured to send and receive command messages with at least one mobile electronic communications device, a messaging server configured to send and receive communications messages with at least one mobile electronic communications device, and the authentication authority, administration server, and messaging server are configured to send and receive data via a data communications network. The authentication authority accepts or denies authentication data for a user received from at least one mobile electronic communications device, stores status information corresponding to authenticated users in the user directory database, and stores an association between each authenticated user and each mobile electronic device that sent authentication data for an authenticated user in the user directory database.

Mobile electronic communications devices including pagers, cellular telephones (cell phones), and devices capable of both data and voice communications, sometimes referred to as "smartphones," each provide different forms of electronic communications. Pager networks generally allow for very simple messages or numeric pages to be sent to a small device known as a pager or beeper. The pager devices are viewed as simple devices because they often are only capable of displaying a callback phone number or brief text message. Some pagers have "two-way" functionality that permits them to send simple messages and respond to incoming pages. Cell phones are also well known, and enable two-way duplex voice communications between the cell phones and landline telephones and other cellular telephones. Cellular telephones may also have limited data transmission capability including the ability to send short text messages using, for example, the Simple Messaging System (SMS). Smartphones are an advanced form of cell phones that provide access to both the standard telephony features of a cell phone and to various forms of data communications that occur over the World Wide Web via a web browser, instant messaging application program, and/or email program. Smartphones often provide access to data networks that were previously reserved for larger electronic devices, such as desktop or notebook computers.
While mobile electronic devices have become ubiquitous in modern society, the devices that are currently available have drawbacks as well. Pagers are very simple to use, but existing pager networks are presently being phased out of use as enterprises increasingly desire the enhanced abilities available through smartphones and the like. While cellular telephones, and smartphones in particular, enhance the data exchanging capabilities in a communication network, they too have drawbacks. Cellular phones are most useful for voice communications between a small group of individuals, but become less useful when sending messages to a larger number of devices. While data protocols like SMS can approximate the alphanumeric functionality of a pager, centrally tracking large numbers of SMS messages to individual mobile devices, and determining if a message has actually been displayed on the mobile device to which it was sent, is not possible in current systems without the use of special software on both the device and another computer. Wireless service providers who provide SMS message services also cannot guarantee the delivery times for SMS communications to the mobile devices. While smartphones are able to communicate using a variety of network protocols, the complex functionality of smartphones may provide too many unused capabilities at prices that render them too inefficient in time-constrained environments, such as a workplace.
Other problems with cellular telephones and smartphones include the limited options in centrally controlling and viewing the contents of communications between these devices. For example, an administrator in a hospital cannot read the content of an SMS message sent by Dr. A to Dr. B, or determine if Dr. B received and read the message. Cell phones and smartphones are also often capable of storing large amounts of information. If a cell phone or smartphone is lost or stolen, much of this information is irretrievably lost or becomes available for nefarious purposes.
The problems with current technologies noted above are particularly acute in situations where a defined group of users need a reliable and simple communications system using mobile electronic devices. Medical professionals, including doctors, nurses, and other support personnel, working together in a hospital are one such example. Other examples include public agencies, such as police and fire departments. Many of these organizations still rely on pagers because of their simplicity, and because pager networks have historically had improved functionality over alternative mobile communications devices within buildings. For example, while modern cellular networks have broad geographic coverage, these networks still have difficulty in sending and receiving signals with devices within shielded structures, such as hospitals and police and fire stations. In the past, pager networks had improved coverage in these structures because of the very low bandwidth requirements of pagers, and because most pagers only received transmissions from the pager network and did not need to transmit back to the network. Pagers also provide a broadcast functionality, allowing for "one-to-many" communications where a single message is broadcast to many pagers simultaneously. In contrast, cellular phone systems generally send messages on a slower sequential basis, with one message sent to one recipient cell phone at a time. Despite these pager system advantages, the limitations in pager functionality in view of other more robust data exchanging devices render existing pager systems less useful for some modern professionals.
The drawbacks of current mobile communications devices and networks described above limit the use of these devices. A mobile electronic device communications system that allows for complex messaging and communications while providing improved reliability and security in shielded buildings is desired.

System and method for administration and operation of one or more mobile electronic communications devices


A compound logic circuit including one NAND gate constituted by two p-channel transistors and two n-channel transistors and one NOR gate constituted by two p-channel transistors and two n-channel transistors. The compound logic circuit is characterized by one of the two p-channel transistors contained in the NAND gate being used as one of the two p-channel transistors contained in the NOR gate and one of the two n-channel transistors contained in the NAND gate being used as one of the two n-channel transistors contained in the NOR gate.

1. Field of the Invention
The present invention relates to a compound logic circuit which is composed of a NAND gate circuit and a NOR gate circuit.
2. Description of the Related Art
For example, consider a compound logic circuit formed on one integrated circuit chip. In case the compound logic circuit is composed of a NAND gate circuit and a NOR gate circuit both of which is formed of CMOS transistors, in general, the NAND gate circuit is formed of quite different transistors from the NOR gate circuit.
FIG. 2 is a circuit diagram showing this type of compound logic circuit composed of a NAND gate circuit and a NOR gate circuit according to the related art of the invention.
As shown in the upper part of FIG. 2, one NAND gate circuit 10 is composed of four transistors 11 to 14, that is, two p-channel MOS transistors 11, 12 (referred to as a PMOS transistor) and two n-channel MOS transistors 13, 14 (referred to as a NMOS transistor).
AS shown in the lower part of FIG. 2, one NOR gate circuit 20 is also composed of four transistors 21 to 24, that is, two PMOS transistors 21, 22 and two NMOS transistors 23, 24.
As will be obvious from FIG. 2, the NAND gate circuit 10 is composed of the dedicated transistors which are independent of the transistors composing the NOR gate circuit 20.
This type of compound logic circuit according to the related art of the invention requires each two PMOS transistors and each two NMOS transistors, that is, eight transistors in total for composing one NAND gate circuit and one NOR gate circuit. It means that the type of compound logic circuit needs a larger area on the integrated circuit chip occupied by the compound logic circuit.

Compound logic circuit having NAND and NOR gate outputs and two transistors connected within both gate circuits


The present invention achieves increased filler interaction by incorporating a small amount (a few units per chain of rubbery polymer) of a conjugated triene monomer, such as alloocimene, randomly throughout the polymer chain of a rubbery polymer or at the chain ends of the rubbery polymer. The incorporation of the conjugated triene monomer leads to the formation of a polymer containing highly reactive conjugated diene units. These conjugated diene units can chemically react with carbon black leading to superior reinforcement. Alternatively, these conjugated diene units can be used for functionalization of the polymer with silica interactive/reactive groups using Diels Alder reactions. This functionalization of the rubbery polymer can conveniently be conducted in a mixer, such as a Banbury mixer, a mill mixer, or the like.

The rubber compositions utilized in making rubber articles are typically filled with carbon black and/or silica to attain desired physical and chemical characteristics. The interaction between rubber and the filler in such rubber compositions has a profound effect on the physical properties of vulcanizates. In fact, the interaction between the rubber and the filler regulates the degree of dispersion of the filler, the formation of elastomer-filler interface, and the filler-filler network. All of these interactions have a significant effect of the physical properties of the cured rubber composition, such as stress-strain properties, energy loss under cyclic load, abrasion resistance, and tear propagation resistance. Increased polymer filler interaction enables dispersion the filler to a finer degree to achieve a higher level of reinforcement. It also permits the incorporation of higher amounts of the filler and/or for the incorporation of fillers which cannot be properly dispersed into conventional rubbers.
The importance of attaining better rubber/filler interaction has been appreciated for many years and has been the subject of numerous research projects throughout the rubber industry and within academic settings. Attaining improved rubber/filler interaction is of particular interest to manufacturers of rubber products such as tires, hoses, power transmission belts, conveyor belts, windshield wiper blades, and a multitude of other industrial rubber products and consumer goods. One recognized approach for attaining better compatibility between rubbery polymers and fillers is to functionalize the rubbery polymer with moieties that improved interaction with the filler. For instance, rubbery polymers can be functionalized with amines to attain better interaction with carbon black and silica.
U.S. Pat. No. 4,935,471 discloses a process for preparing a polydiene having a high level of affinity for carbon black which comprises reacting a metal terminated polydiene with a capping agent selected from the group consisting of (a) halogenated nitriles having the structural formula X-A-C≡N, wherein X represents a halogen atom and wherein A represents an alkylene group containing from 1 to 20 carbon atoms, (b) heterocyclic aromatic nitrogen containing compounds, and (c) alkyl benzoates. The capping agents disclosed by U.S. Pat. No. 4,935,471 react with metal terminated polydienes and replace the metal with a terminal cyanide group, a heterocyclic aromatic nitrogen containing group or a terminal group which is derived from an alkyl benzoate. For example, if the metal terminated polydiene is capped with a nitrile, it will result in the polydiene chains being terminated with cyanide groups. The use of heterocyclic aromatic nitrogen containing compounds as capping agents can result in the polydiene chains being terminated with a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an indolizinyl group, an isoindolyl group, a 3-H-indolyl group, a cinnolinyl group, a pteridinyl group, a .beta.-carbolinyl group, a perimidinyl group, a phenanthrolinyl group or the like.
U.S. Pat. No. 4,935,471 also discloses that lithium amides are highly preferred initiators because they can be used to prepare polydienes which are terminated with polar groups at both ends of their polymer chains. The extra polar functionality provided by lithium amides results in increased interaction with carbon black resulting in better polymer-carbon black dispersion. The lithium amides disclosed by U.S. Pat. No. 4,935,471 include lithium pyrrolidide. U.S. Pat. No. 4,935,471 also indicates that preferred initiators include amino alkyl lithium compounds of the structural formula:
wherein A represents an alkylene group containing from 1 to 20 carbon atoms, and wherein R1 and R2 can be the same or different and represent alkyl groups containing from 1 to 20 carbon atoms.
It is also desirable for synthetic rubbers to exhibit low levels of hysteresis. This is particularly important in the case of rubbers that are used in tire tread compounds. Such polymers are normally compounded with sulfur, carbon black, accelerators, antidegradants and other desired rubber chemicals and are then subsequently vulcanized or cured into the form of a useful article. It has been established that the physical properties of such cured rubbers depend upon the degree to which the carbon black is homogeneously dispersed throughout the polydiene rubber. This is in turn related to the level of affinity that carbon black has for the rubber. This can be of practical importance in improving the physical characteristics of rubber articles that are made utilizing polydiene rubbers. For example, the rolling resistance and tread wear characteristics of tires can be improved by increasing the affinity of carbon black to the rubbery polymers utilized therein. Therefore, it would be highly desirable to improve the affinity of a given polydiene rubber for carbon black and/or silica. This is because a better dispersion of carbon black throughout polydiene rubbers which are utilized in compounding tire tread compositions results in a lower hysteresis value and consequently tires made therefrom have lower rolling resistance. It is also known that a major source of hysteresis is due to polymer chain ends that are not capable of full elastic recovery. Accordingly, improving the affinity of the rubber chain ends to the filler is extremely important in reducing hysteresis.
U.S. Pat. No. 6,080,835 discloses a functionalized elastomer comprising: a functional group defined by the formula:
where R1 is a selected from the group consisting of a divalent alkylene group, an oxy-alkylene group, an amino alkylene group, and a substituted alkylene group, each group having from about 6 to about 20 carbon atoms, R2 is covalently bonded to the elastomer and is selected from the group consisting of a linear-alkylene group, a branched-alkylene group, and a cyclo-alkylene group, each group having from about 2 to about 20 carbon atoms.
U.S. Pat. No. 5,932,662 discloses a method of preparing a polymer comprising: preparing a solution of one or more anionically polymerizable monomers in a solvent; and, polymerizing under effective conditions, said monomers in the presence of a polymerization initiator having the formula
wherein R1 is a divalent alkylene, an oxy- or amino-alkylene having from 6 to about 20 carbon atoms; and, R2 is a linear-alkylene, branched-alkylene, or cyclo-alkylene having from about 2 to about 20 carbon atoms, Li is a lithium atom bonded directly to a carbon atom of R2; and R3 is a tertiary amino, an alkyl having from about 1 to about 12 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; an alkaryl having from about 7 to about 20 carbon atoms; an alkenyl having from about 2 to about 12 carbon atoms; a cycloalkyl having from about 5 to about 20 carbon atoms; a cycloalkenyl having from about 5 to about 20 carbon atoms; a bicycloalkyl having from about 6 to about 20 carbon atoms; and, a bicycloalkenyl having from about 6 to about 20 carbon atoms; where n is an integer of from 0 to about 10.
U.S. Pat. No. 6,084,025 discloses a functionalized polymer prepared by a process comprising the steps of: preparing a solution of a cyclic amine compound, an organolithium compound, and from 3 to about 300 equivalents, based upon one equivalent of lithium, of a monomer selected from vinyl aromatic monomers, and mixtures thereof, where said cyclic amine compound is defined by the formula:
where R2 is selected from the group consisting of an alkylene, substituted alkylene, bicycloalkane, and oxy- or N-alkylamino-alkylene group having from about 3 to about 16 methylene groups, N is a nitrogen atom, and H is a hydrogen atom, thereby forming a polymerization initiator having the formula A(SOL)yLi, where Li is a lithium atom, SOL is a divalent hydrocarbon group having from 3 to about 300 polymerized monomeric units, y is from 0.5 to about 3, and A is a cyclic amine radical derived from said cyclic amine; charging the solution containing A(SOL)yLi with from about 0.01 to about 2 equivalents per equivalent of lithium of a chelating reagent, and an organic alkali metal compound selected from compounds having the formula R4OM, R5C(O)OM, R6R7NM, and R8SO3M, where R4, R5, R6, R7, and R8 are each selected from alkyls, cycloalkyls, alkenyls, aryls, or phenyls, having from 1 to about 12 carbon atoms; and where M is Na, K, Rb or Cs, and sufficient monomer to form a living polymeric structure; and quenching the living polymeric structure.
U.S. Pat. No. 6,344,538 discloses functionalized monomers and polymerized functionalized monomers selected from the group consisting of 2-(N,N-dimethylaminomethyl)-1,3-butadiene, 2-(N,N-diethylaminomethyl)-1,3-butadiene, 2-(N,N-di-n-propylaminomethyl)-1,3-butadiene, 2-(cyanomethyl)-1,3-butadiene, 2-(aminomethyl)-1,3-butadiene, 2-(hydroxymethyl)-1,3-butadiene, 2-(carboxymethy)-1,3-butadiene, 2-(acetoxymethyl)-1,3-butadiene, 2-(2-alkoxy-2-oxoethyl)-1,3-butadiene, 2,3-bis(cyanomethyl)-1,3-butadiene, 2,3-bis(dialkylaminomethyl)-1,3-butadiene, 2,3-bis(4-ethoxy-4-4-oxobutyl)-1,3-butadiene and 2,3-bis(3-cyanopropyl)-1,3-butadiene, and methods for preparing such functionalized diene monomers and polymers.
U.S. Pat. No. 6,211,321 discloses a diene rubber comprising 40 to 99.99% by weight of combined units of a conjugated diene monomer, 0 to 50% by weight of combined units of an aromatic vinyl monomer, and 0.01 to 20% by weight of combined units of other vinyl monomer comprising at least one of tertiary amino-containing vinyl monomer and halogen-containing vinyl monomer and wherein at least part of said combined other vinyl monomer is quaternized to form quaternized tertiary amino-containing vinyl monomer units, with the provisos that when said other vinyl monomer comprises combined tertiary amino-containing vinyl monomer units it is quaternized with a monohalogenated hydrocarbon and when said other vinyl monomer comprises combined halogen-containing vinyl monomer units it is quaternized with a tertiary amine, and having a Mooney viscosity ML1+4 at 100° C. of 10 to 200, wherein the tertiary amino-containing vinyl monomer is a compound of the formula CH2═CR11A2NR12R13 where R11 is a hydrogen atom or a lower alkyl group, R12 and R13 are each, independently, an alkyl group, an aryl group or an aralkyl group, A2 is an alkylene group, an arylene group, an arylene-alkylene group, an alkylene-arylene group, or a linking group of the general formula —C(═O)-M-R14—, in which M is an oxy group or an NH group, and R14 is an alkylene group, an arylene group, an arylene-alkylene group or an alkylene-arylene group, and R12 or R13 may be combined with A2 to form a heterocyclic ring, and wherein the combined units of the quaternized tertiary amino-containing vinyl monomer have the formula:
where R1 is a hydrogen atom or a lower alkyl group, R2, R3 and R4, are each, independently, an alkyl group, an aryl group or an aralkyl group, A1 is an alkylene group, an arylene group, an arylene-alkylene group, an alkylene-arylene group, or a linking group of the general formula —C(═O)-M-R5—, in which M is an oxy group or an NH group, and R5 is an alkylene group, an arylene group, an arylene-alkylene group or an alkylene-arylene group, and R2 or R3 may be combined with A1 to form a heterocyclic ring, and X is a halogen atom.
U.S. Pat. No. 6,057,397 discloses a silica-containing diene rubber composition that is reported to be superior in resilience (which is an indication of rolling resistance), at least equal, in tensile strength and abrasion resistance, to carbon black-containing diene rubber compositions, and good in processability and hardness characteristics. The silica-containing diene rubber composition disclosed in U.S. Pat. No. 6,057,397 is characterized by containing, as the diene rubber component, a hydroxyl group-containing diene rubber having a weight-average molecular weight of 50,000 or more, or a blend of the hydroxyl group-containing diene rubber and other diene rubber. This composition is produced by a process which uses, as the diene rubber component, a hydroxyl group-containing diene rubber having a weight-average molecular weight of 50,000 or more, or a combination of the hydroxyl group-containing diene rubber and other diene rubber and wherein the mixing of components is conducted by mixing the diene rubber component with at least part of a required amount of silica and then mixing the resulting mixture with the remainder of silica and other compounding agents.
U.S. Pat. No. 6,114,432 is a diene rubber composition comprising 100 parts by weight of a diene rubber component composed of 10 100 weight percent of an amino group-containing diene copolymer rubber (A) having a composition (based on the bound amount) of 40 99.95 weight percent of a conjugated diene monomer, 0.05 20 weight percent of an amino group-containing monomer and 0 55 weight percent of an aromatic vinyl monomer, and 0 90 weight percent of another diene rubber (B), and 10 150 parts by weight of silica having a specific surface area of 50 220 m2/g as determined by nitrogen absorption (BET method), and having excellent heat build-up resistance, tensile properties, abrasion properties and processability, and a preparation method thereof.
U.S. Pat. No. 6,627,721 discloses a rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one functionalized monomer having of the structural formula:
wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, and wherein R1 and R2 can be the same or different and represent hydrogen atoms or a moiety selected from the group consisting of
wherein R3 groups can be the same or different and represent alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, allyl groups, and alkyloxy groups of the structural formula —(CH2)y—O—(CH2)z—CH3, wherein Z represents a nitrogen containing heterocyclic compound, wherein R4 represents a member selected from the group consisting of alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, and allyl groups, and wherein n and x represent integers from 1 to about 10, with the proviso that R1 and R2 can not both be hydrogen atoms.
U.S. Pat. No. 7,108,033 discloses a rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one leaving group-bearing monomer having the structural formula:
wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, wherein R′ represents a methyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, with the proviso that if R represents an alkyl group then R′ represents a hydrogen atom, wherein R1 and R2 can be the same or different, wherein R1 represents an alkyl group that is functionalized with a leaving group, wherein R2 represents a moiety selected from the group consisting of hydrogen atoms, alkyl groups containing from 1 to 18 carbon atoms, aryl groups containing from 6 to 18 carbon atoms, alkaryl groups containing from 7 to 18 carbon atoms, and alkyl groups that are functionalized with a leaving group.
U.S. Pat. No. 7,108,033 further reveals a tire which is comprised of a generally toroidal-shaped carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread to said beads, wherein said tread is adapted to be ground-contacting, and wherein said tread is comprised of (I) a filler, and (II) rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one monomer having the structural formula:
wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, wherein R′ represents a methyl group or a hydrogen atom, with the proviso that if R represents an alkyl group then R′ represents a hydrogen atom, wherein R1 and R2 can be the same or different, wherein R1 represents an alkyl group that is functionalized with a leaving group, wherein R2 represents a moiety selected from the group consisting of hydrogen atoms, alkyl groups containing from 1 to 18 carbon atoms, aryl groups containing from 6 to 18 carbon atoms, alkaryl groups containing from 7 to 18 carbon atoms, and alkyl groups that are functionalized with a leaving group.

Copolymers of conjugated triene monomers for improved filler interaction


Novel polymorphisms of prokaryotic topoisomerase type II Gyr A, Gyr B and parC gene loci are provided. These polymorphisms differentiate very closely related organisms and provide a means to identify pathogenicity and drug resistance. For example, drug resistance such as resistance to methicillin, a drug which is not metabolically tied to topoisomerase function, may be determined by polymorphisms in the Gyrase A locus. Identification of such drug resistance by such unrelated loci is indicative of heretofore unrecognized [sub]species of Staphylococcus aureus.

Pathogenic strains of E. coli are a common target for identification in clinical settings. For example, E. coli O157:H7 is a pathogenic bacterium that causes severe diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (Nataro and Kaper 1988, Whittam 1993). Rapid identification of E. coli O157:H7, other shiga toxin producing E. coli ("STEC"), other entero-pathogenic E. coli (e.g., O26:H11) and nonpathogenic E. coli is critical for proper treatment and control of epidemics (McDonald and Osterholm, 1993, Majkowski, 1997).
Additionally, in connection with identifying such bacteria, there is also interest in discovering which drugs are effective against such microorganisms so that a treatment regimen can be initiated. Many of the current methods that are used to diagnose pathogenic and drug resistant strains of bacteria require the isolation of the suspect sample from bacterial monocultures that must be incubated over a number of days only after which the pathogenic strain can be identified by performance of biochemical tests. (see review in Swaminathan 1994). Such tests include phage typing, sorbitol fermentation, beta-glucuronidase production, protein identification by immunological means, colony hybridization with DNA probes, and restriction fragment length polymorphism ("RFLP") analysis.
Assays incorporating nucleic acid amplification have the potential to lower the costs and shorten considerably the assay time due to the increased organism-specific sensitivity and the ability to identify particular organisms (genera and strains) directly from mixed culture samples. Such shortening of time and lowering of costs will allow patient samples to be tested for the identification of specific pathogenic strains on a routine basis in contrast to the current practice of testing for such organisms on an "as needed" basis.
Numerous nucleic acid based methodologies have been devised for microorganism identification including the use of DNA amplification (see Arbeit 1995, Whelen and Pershing 1996). One method, the random amplification of polymorphic DNA, ("RAPD"), uses a single random primer in a polymerase chain reaction ("PCR") to obtain a fingerprint of random amplification products. The RAPD technique suffers from the need to establish monocultures prior to strain detection and identification. Moreover, the RAPD technique requires the skill of a technician trained to interpret a complex pattern of bands generated by the technique.
Another method targets regions of nucleotide sequence that encode, or are related to the production of, a pathogen's toxin. For example, specific gene loci for shiga toxins, such as slt-I, and slt-II afford the ability to distinguish E. coli O157:H7 from strains of non-toxin producing pathogens. However, the use of toxin specific loci are limited because testing is only applicable to a narrow range of microbial species that encode the specific toxin being tested.
Another bacterial identification system uses 16S-ribosomal RNA (Weisberg et al. 1991, Neefs et al. 1993). The 16S system is less than desirable because multiple copies of the rRNA gene may contain multiple polymorphisms (a situation known as heteroplasmy) making identification of a specific bacterial strain difficult. Additionally, while the system is able to separate unknown bacteria to the species level, it is not possible to differentiate subspecies strains.
Still other methods which use genetic sequences in hybridization oriented identification are documented. In particular, a method of identifying microorganisms using polymorphisms within the type II DNA topoisomerase genes has been disclosed (Annu. Rev. Genet., 1996, Vol. 30, pp 79–107, by W. M. Huang, Antimicrobial Agents and Chemotherapy, September 1995, Vol. 39, No. 9, pp 2145–2149, by I. Guillemin et al., U.S. Pat. No. 5,645,994, by W. M. Huang, all of which are herein incorporated by reference).
Prokaryotic and eukaryotic type II topoisomerases are related in their structure and function. These molecules are essential for maintenance of DNA superhelicity for DNA replication. One type II topoisomerase from bacteria is DNA gyrase. Bacterial DNA Gyrase is composed of two subunits, GyrA and GyrB. The amino acid sequence of the GyrA subunit is highly conserved between prokaryotic and eukaryotic organisms. However, at the DNA level codon usage and G-C content are markedly divergent. The divergence in the nucleic acid sequences has provided the basis for the development of rapid methodology to identify new bacterial topoisomerase genes (see W. M. Huang 1996).
Comparison of a variety of prokaryotic Gyrase A genes shows that the length of the protein encoded by such genes is in the range of 850 amino acids. The overall identity among GyrA proteins from these different organisms is only about 40% with the greatest variability occurring in the C-terminal third of the sequences. However, the N-terminal portion of the genes are highly conserved, which conservation allows the grouping of the various species in a manner consistent with the grouping elucidated using rRNA sequence analysis. (see Neef, 1993, and Olsen, 1994).
The known GyrB subunit gene sequences encode proteins of between 650 and 800 amino acids in length. In general, the GyrB proteins from various organisms tested share approximately 60% overall amino acid sequence identity.
A second type II topoisomerase gene known in E. coli has sequence identity with the GryA. Specifically, the parC gene has 36% identity with and is generally shorter than the GryA gene encoding a protein of about 750 amino acids.
Alignment of type II topoisomerase genes from a variety of organisms has revealed that the N-terminal region is highly conserved at the amino acid level such that there are at least nine regions having at least five invariant amino acids interspersed with more variable regions. The consensus regions provide DNA sequences that are useful for designing "universal" primers for the amplification of intervening variable regions. The availability of nucleic acid sequences of the intervening variable regions has allowed identification of new topoisomerase genes in such organisms and consequently the ability to study biodiversity at the species level.
For example, U.S. Pat. No. 5,645,994 by W. M. Huang discloses a method of identifying species of bacteria by amplifying variable or "signature" sequences that are interspersed between the conserved sequences. The flanking conserved sequences are used to design universal primers for amplification of the signature sequences. Following amplification, the signature sequences are cloned and sequenced and the sequence is compared against a database of signature sequences from multiple species. Likewise, Huang discloses that alignment of the DNA sequences from isolates of one genus can be used to examine micro-diversity among species of a genus.
The current invention provides numerous polymorphisms recently discovered in the GyrA, GyrB, and parC subunits of topoisomerase type II genes that have application in the detection and identification of subspecies of pathogenic and nonpathogenic bacteria. The current invention also provides polymorphisms identified in the type II isomerases that are associated with drug resistance wherein the proteins and regulation of the genes in which the polymorphisms are found are not affected by or biochemically associated with the function of the drug.
For example, with regard to drug resistance, outbreaks of drug resistant strains of Staphylococcus aureus occur periodically in clinical environments such as in hospitals where there may be concentrations of patients suffering from compromised immune systems (Herwaldt and Wenzel 1995). Rapid identification of such resistant strains is recognized as being crucial for the adoption of appropriate treatment regimens (Morita 1993). Most important in such resistance outbreaks has been resistance to methicillin. With respect to methicillin resistance, a gene locus frequently responsible for such resistance is the mecA locus (see Archer and Neimeyer 1994) which has been, along with surrounding noncoding regions, the target of amplification-based assays (e.g., Murakami et al. 1991). While the mecA gene provides a direct link to methicillin resistance, the locus is specific to the genus Staphylococcus and thus is of limited utility as a general diagnostic because only drug resistant Staphylococcus aureus should be identified. Moreover, because mecA DNA is susceptible to horizontal transfer between bacteria, (Archer and Niemeyer 1994, Wu et al. 1996), the potential for misidentification exists causing serious drawbacks to the use of mecA as an identification marker for pathogenic S. aureus.
In contrast, topoisomerase type II polymorphisms have been used to identify drug resistance in microorganisms. Specifically, the Gryase A gene has been used to study resistance of certain bacterial strains to fluoroquinolone ("FQ") antibiotics. (e.g., Mycobacterium sp. Guillemin 1995, Campylobacter sp. and Helicobacter sp. Husmann 1997, and Staphylococcus aureus Wang 1998). Biochemically, FQ resistance functions because the mutation in the GyrA protein sequence interferes with the ability of the antibiotic to interact with GyrA/DNA complexes resulting in continued growth and division of the replicating organism. It has been observed that the mutations responsible for FQ resistance are clustered within a small pocket of amino acids in the N-terminal portion of the protein. Since the biochemistry and the genetics of the GyrA gene suggest the involvement of a small number of amino acids, the amino acids at these positions can be correlated with the general antibiotic susceptibility of these bacteria. Thus, as suggested by Guillemin, a screening method may be developed to identify species having resistance to FQ antibiotics based on the mutations in the Gyrase A gene.
Of greater significance, we have discovered polymorphisms in the Gyrase A gene that are associated with non-FQ antibiotics drug resistance that is not involved in or associated with the functionality of topoisomerase:DNA complexes. This discovery is very important because it indicates that polymorphisms in the GyrA subunit are indicative of subtle but distinct differences between organisms where there is no known evolutionary pressure that would assist an organism in developing such genetic divergence.
Although the prior disclosures are directed to the use of Gyrase A gene polymorphisms in the identification of species of organisms and at least one class of antibiotic resistance, such prior disclosures have failed to recognize or disclose a recognizable association between topoisomerase type II sequence polymorphisms and significant divergence between very closely related organisms. For example, pathogenic strains of E. coli that have been isolated and classified as strain 0157:H7 have been found to include numerous polymorphisms. Thus, it is questionable whether classifying such isolates as only one strain (i.e. 0157:H7) is satisfactory. Likewise, it has been found that E. coli strain K12, which has traditionally been attributed to be the same strain as wild type E. coli ATCC 11775, is divergent from the wild type strain and is actually a separate "laboratory" strain as indicated by divergence in the Gyrase A gene. (see below)
The current invention recognizes the importance of these subtle divergences within the GyrA, GyrB, and parC proteins of the topoisomerase family and provides numerous polymorphisms useful for the identification of closely related organisms that may be heretofore unrecognized subspecies variations within populations of organisms that have traditionally been classified together as a single species.

Topoisomerase type II gene polymorphisms and their use in identifying drug resistance and pathogenic strains of microorganisms


An electromagnetic induced accelerator based on coil-turn modulation, including inner and outer cylinders with different diameters, the cylinders being coaxially disposed to form a channel which is a spatial portion therebetween; a discharging coil wound spirally inward along the upper surface of the channel for generating plasma by inducing a magnetic field and secondary current in the channel; and inner and outer coils wound helically around along the inner surface of the inner cylinder and the outer surface of the outer cylinder in parallel with each other for accelerating plasma in the direction of a common axis of the inner and outer cylinders by offsetting the magnetic field induced in the direction of the axis.

1. Field of the Invention
The present invention relates to an electromagnetic induced accelerator and, more particularly, to an electromagnetic induced accelerator using one single strand of coil to accomplish the purposes of generating plasma, inducing a magnetic field and secondary current and accelerating movement of plasma, respectively, or using a strand of coil to accomplish all of the purposes.
2. Description of the Related Art
An electromagnetic induced accelerator, or a plasma accelerator, operates to accelerate movement of plasma existing or generated in a spatial portion by electric and magnetic energy.
In the early stage, a plasma accelerator was developed for an ion engine of a rocket for long-distance space travel and nuclear fusion, but it has been used for a wafer etching technique in a semiconductor manufacturing process.
Plasma is the gaseous state of hot ionized material consisting of negatively charged electrons and positively charged ions with approximately equal concentrations of both, so that the total gas is in approximately charge neutral. Therefore, it is called the fourth state of matter besides the three states of matter-solid, liquid and gas.
As the temperature rises, most of all matter changes from a solid state, to a liquid state and then to gas state in turns. At several ten thousands of degrees (° C.), a gas splits into electrons and atomic nucleuses, resulting in a plasma state.
FIG. 1 is a cut-away perspective view of an electromagnetic induced accelerator in accordance with the related art.
With reference to FIG. 1, an electromagnetic induced accelerator comprises inner and outer circular loop coils 10, 20, a channel 40 contacting the inner circular loop coils 10 on its internal portion and outer circular loop coils 20 on its external portion, an outer cylinder 30, an inner cylinder 60 and a discharging coil 50 disposed underneath the channel 40.
The inner and outer loop coils 10, 20 are arranged coaxially in parallel to each other, and a current is applied to the coils 10, 20 circumferentially around the channel 40. A current is applied to the coils 10, 20 in the same direction, clockwise or counter-clockwise and this induces a magnetic field across the channel 40. In electromagnetic induced accelerators in accordance with the related art, inner and outer loop coils comprise a plurality of coils, respectively, and the coils 10, 20 are provided to gradually diminish the magnetic field induced in the channel 40 in the axial direction by reducing current flowing through each coil winding around in the axis direction. The magnetic field is induced across the channel 40 to be perpendicular to the axial direction and gradually decreases along the axial direction.
The magnetic field induced in the channel induces a secondary current in accordance with Maxwell's equation. Plasma generated in the channel 40 by the discharging coil 50 accelerates in the axial direction toward an exit 70 by the magnetic field induced across the channel 40 and the secondary current.
Such an electromagnetic induced accelerator in accordance with the related art is based on a B-field modulation method which accelerates plasma by causing a difference in magnetic pressure between the entrance side 80 and the exit 70 of the channel by applying large current and small current to the loop coils winding around the entrance side 80 and the exit side 70, respectively.
Accordingly, such B-field modulation requires a plurality of inner loop coils 10 installed in the inner cylinder 60 to independently apply different driving currents to each inner loop coil 10. It means that a plurality of pull-in wires for the inner loop coils 10 should be externally pulled in the inner cylinder 60. Accordingly, the number of the inner loop coils 10 to wind around the internal surface of the inner cylinder 60 is limited in case that the inner cylinder 60 is small in diameter. Further, influence of the pull-in wires to the magnetic field induced by the coils is so high. As a result, it is hard to induce the magnetic field as designed due to the coupling noises of the coils.

Electromagnetic induced accelerator based on coil-turn modulation


An imaging device includes a refractive imager lying in an optical path, and optionally a telescope that directs the optical path to the refractive imager. The refractive imager includes a first lens group that forms an intermediate image of a scene on the optical path, wherein the first lens group includes a first-lens-group positive-power lens, and a first-lens-group negative-power lens. A second lens group relays the intermediate image to a final image surface on the optical path, wherein the second lens group includes a second-lens-group positive-power lens, and a second-lens-group negative-power lens. A third lens group may be selectively inserted into the optical path between the first lens group and the second lens group and selectively removed from the optical path. The third lens group includes a third-lens-group positive-power lens, and a third-lens-group negative-power lens.

Imaging devices such as imaging sensor systems typically include an imaging sensor, and optics through which the optical path from the viewed scene passes to reach the imaging sensor. The optics serve to provide the desired focal length and field of view of the scene, and to focus the image onto the imaging sensor. In some applications, it is desirable that the optical system selectively provide two or more fields of view, such as a wide-angle field of view for general searching of a large area, and a narrow-angle field of view for higher-magnification, more-specific analysis of a small portion of the scene that is found to be of interest.
The imaging sensor may be selected for viewing any desired wavelength range, and imaging sensors are known for use in different wavelength ranges. Such wavelength ranges include, for example, wavelengths in the visible, the near infrared, the medium-wavelength infrared, and/or the long-wavelength infrared. Infrared sensors are typically cooled to cryogenic temperatures for optimal performance. The optics of the imaging sensor system must be compatible with the cold shielding required by the sensor, when such a cryogenic sensor is used.
In an application of interest, an imaging device requires imaging in two or more fields of view, with a straightforward approach for switching between the two fields of view. The imaging must be accomplished in two or more infrared wavelength ranges using a sensor that is cooled to the cryogenic range. Although it is conceivable to move the imaging sensor along the beam path when the field of view is switched, it is far preferable that both the focal surface of the optics and the cold stop of the cryogenic shielding remain at a fixed location when the field of view is switched. The imaging sensor, the cooling structure, and the associated cold stop may therefore remain at a fixed location along the beam path. No such imaging device is currently available, and there is a need for such an imaging device. The present invention fulfills this need, and further provides related advantages.

Dual-band, dual-focal-length, relayed refractive imager


Reducing or eliminated color-dependent vignetting in a digital camera includes: providing, for each color that said camera can image, a raw array of data corresponding to a desired scene; and changing the raw arrays such that the array for each color exhibits substantially the same amount of vignetting so as to reduce color-dependent vignetting in a composite image based upon each of the changed arrays.

Non-color-dependent vignetting is a photographic phenomenon in which the picture taken by the camera exhibits a darkening from the center to the corners irrespective of what color is present. Photographs taken by both a film camera and images taken by a digital camera can exhibit vignetting. Some amount of vignetting is acceptable, and actually desirable from an artistic sense. But an excessive amount of vignetting will be objectionable to most people.
In either a film camera or a digital camera, such vignetting is caused by having to capture an image on a small flat surface, namely the film or the optical-to-electronic imager, e.g., a charge coupled device ("CCD"). In either type of camera, rays of light striking the corners of the film/imager travel a longer path and arrive at a different angle of incidence than rays of light which impinge directly upon the center of the film/imager.
Differences in the response of the CCD to light impinging directly versus light impinging at an angle produce non-uniformity in the data corresponding to an image, which is characterized as vignetting. The lens system can also effect vignetting. Plus, if the camera uses a flash device, vignetting can also be due to the flash device's variation in illumination intensity across the subject.
As the name suggests, color-dependent vignetting is to be understood as a vignetting pattern exhibited by a camera in response to a particular color of light. A typical color image sensor in a digital camera includes a mosaic type of image sensor, i.e., a CCD over which is formed a filter array that includes the colors red, green and blue. Each pixel has a corresponding red, green or blue filter area. A typical arrangement of the color filter array is the Bayer pattern that repeats a two-line pattern. The first line contains alternating red and green pixels and the second line contains alternating blue and green pixels. The larger number of green pixels represents an adaptation for the increased sensitivity to green light exhibited by the human eye. The separate color arrays, or planes, of data images formed by the sensor are then combined to create a full-color image after suitable processing.
Color-dependent vignetting can be exhibited in addition to non-color-dependent vignetting. The human eye is very sensitive to color-dependent variation. Hence, color-dependent vignetting is very objectionable, even in small amounts.
Color-dependent vignetting can be minimized by using higher quality lens systems, image sensors and/or flash devices. But this is an impractical solution in a situation in which the minimization of system cost and/or system complexity are important design criteria.

Method and apparatus for color non-uniformity correction in a digital camera

Hewlett-Packard Development Company, L.P.


To make it possible to decrease an X-ray exposure on an operator and to obtain an image of high quality upon fluoroscopy operation an X-ray tube is rotated to acquire data, an X-ray radiation dose is set to "0" in a predetermined angular range including an angle at which the alignment of the X-ray tube with the operator's hand is brought about, and the X-ray radiation dose is set to an ordinary one at an angle in a range other than that angular range. The predetermined angular range is established using a light beam which enables to see what part of the field has no X-ray radiation exposure, thereby increasing his safety.

When a fluoroscopy is performed with an X-ray CT apparatus, as shown in FIG. 1, during which an X-ray tube 1b and an X-ray detector 2a are rotated to acquire data for producing an image, an operator stabs a biopsy needle N into a subject K.
A hatched region in FIG. 2 represents a space through which the X-ray passes during one rotation of the X-ray tube 1b and the X-ray detector 2a. As will be understood from FIG. 2, there is a problem in that the operator is exposed to the X-ray because the operator's hand lies in the space through which the X-ray passes.
In order to decrease an X-ray radiation dose to which the operator is exposed, it is desirable to set the X-ray radiation dose low. However, this will cause another problem in that data cannot be acquired with a good S/N ratio and the image quality is deteriorated.

Fluoroscopy method and X-ray CT apparatus


A semiconductor device and a method for fabricating the same in which a protective oxide layer is formed on an insulating interlayer gap are disclosed. An example semiconductor device includes a semiconductor substrate having lower structures, an insulating interlayer on the semiconductor substrate to cover the lower structures, and an SiH4-oxide layer on the insulating interlayer. The SiH4-oxide has hydrogen constituents removed by displacement to prevent an amorphous material layer from being formed on the insulating interlayer. The example semiconductor device includes a contact hole in the insulating interlayer and the SiH4-oxide layer for exposing predetermined portions of the lower structures. Additionally, the example semiconductor device includes a contact plug formed inside the contact hole to electrically connect the lower structures with a metal line.

As a semiconductor device is more highly integrated, the number of metal lines increases. Meanwhile, a pitch of the metal line decreases gradually. As the pitch of the metal line decreases, a resistance of the metal line increases. Also, a parasitic capacitance between an insulating interlayer for the metal line and the corresponding metal line is generated, thereby deteriorating the characteristics of the semiconductor device. As a result, it is necessary to provide a low dielectric insulating interlayer suitable for the high-integration semiconductor device. Recently, a Boron-Phosphorus Silicate Glass (hereinafter, referred to as "BPSG") layer and a Fluorine Silicate Glass (hereinafter, referred to as "FSG") layer have been developed for use a low dielectric insulating interlayer. Both of these recently developed layer are applied in a wide range of applications.
As shown in FIG. 1, a known semiconductor device includes a semiconductor substrate 1 having lower components. In this state, an insulating interlayer 2 of a BPSG layer or an FSG layer is deposited on the semiconductor substrate 1. Then, a contact hole H is formed in the insulating interlayer 2, and a contact plug 6 is formed therein for an electric contact between the lower components and a metal line 5. Also, a barrier metal layer 7 is additionally formed inside the contact hole H to improve the electric contact of the contact plug 6 and a reflection prevention layer 4 is formed on the insulating interlayer 2 for formation of the contact hole H.
In the drawings, for convenience, the reflection prevention layer 4 is depicted in the completed semiconductor device. However, in fact, after the reflection prevention layer 4 is used to prevent the diffused reflection of pattern light (for example, UV rays) when forming the contact hole H by pattering a photoresist pattern, the reflection prevention layer 4 is completely removed in the semiconductor device by the following polishing process.
In the known semiconductor device, if the insulating interlayer 2 of the BPSG layer or the FSG layer is exposed to the atmosphere without the additional process, an amorphous material layer is unnecessarily formed in the surface of the insulating interlayer 2. To prevent this problem, as shown in the drawings, a protective oxide layer, for example, a SiH4-oxide layer 3 is additionally formed on the insulating interlayer 2. By forming the SiH4-oxide layer 3, it is possible to prevent the amorphous material layer from generating in the surface of the insulating interlayer 2.
The SiH4-oxide layer has the most stable chemical structure among oxide layers formed by plasma, whereby it is possible to effectively prevent the formation of the amorphous material layer. However, because the SiH4-oxide layer contains hydrogen, the hydrogen goes out of an interface during the fabrication process.
In this state, as shown in the drawings, if the reflection prevention layer 4 for forming the contact hole is formed on the corresponding SiH4-oxide layer at an acidity between (ph)3- and (ph)4, as shown in FIG. 2, the hydrogen 3a is rapidly transferred to the reflection prevention layer 4 and is combined with the oxygen 4b of the reflection prevention layer 4, thereby generating the hydroxide group (4a:OH—). As a result, the acidity (ph) of the reflection prevention layer 4 is lowered so that the reflection function of the reflection prevention layer 4 deteriorates.
Under the deterioration in the function of the reflection prevention layer, in case of performing the photoresist pattern process by using the corresponding reflection prevention layer and the process of forming the contact hole by using the photoresist pattern, the completed contact hole H is formed in a barrel type or shape due to a bowing phenomenon generated by the diffused reflection of the reflection prevention layer 4. In this state, if the barrier metal layer 7 and the contact plug 6 are formed without the additional process, it is impossible to stably fill the inside of the contact hole with the barrier metal layer 7 and the contact plug 6. As a result, the metal line 5 may not be stably and electrically connected with the semiconductor substrate 1, thereby deteriorating the quality of the completed semiconductor device.

Semiconductor device and method for fabricating the same


Method and system for reporting to a source user before communication begins communication means usable by both the source and a destination user. Operable communication means at each user's information terminal are stored in a list DB 2 in advance for each user. A selection device 1 receives a destination user designation from the source user who is requesting communication, and acquires the usable communication means of the destination user and the source user respectively from the list DB 2. There are also cases in which the selection device 1 acquires communication means usable by the source user from the selection device 1 or a user terminal 4. Next, the selection device 1 creates a candidate list describing communication means which both parties can use, and sends it from a WWW server, for example, to the source user terminal. Before communication begins, the candidate list is displayed at the source user terminal by a WWW browser, for example.

1. Technical Field
The present invention relates to communication systems wherein users communicate amongst themselves utilizing information terminals on a network carrying a plurality of communication means. More specifically, among such communication systems, it relates to a communication system wherein users can select communication means ahead of initiating communication.
2. Description of Related Art
In recent years, various types of communication means have been installed in information terminals on networks: telephone functions, email devices, instant messaging devices. Examples of this sort of information terminal include, for example, the PC (personal computer), WS (work station), portable telephones, and portable information terminals used in PHS (Japan's personal handy-phone system, comparable to PCS, personal communications service in the United States). When communication is called for, users make use of the various types of communication means to suit their situations, circumstances or preferences.
Given this situation, when requesting communication it is necessary to consider the status or circumstances of the party from which communication is requested, not just the party requesting communication. In Laid-Open Patent Application 1995-250132 and Laid-Open Patent Application 1996-140158 a user registers the communication means he himself uses in advance. When a user requests communication with another user, notification occurs as to whether or not it is possible to communicate with a communication means registered by the other user.
Also, Laid-Open Patent Application 1998-55492 provides technology whereby a communication means usage possibility indication is dynamically modified according to changes in the communication means that a party can use, and before communication begins the party is notified of usable communication means. In this invention each user registers usable communication means for specified statuses in advance. Communication means usable by the user who is designated the communication destination (simply "destination user" hereinafter) are reported to the party requesting communication in accordance with that user's status.
All of the foregoing art displays only the destination user's usable communication means. Therefore the user who is sending a communication request (simply "source user" hereinafter) to someone must search the other party's usable communication means for communication means which he himself can use. This puts a heavy burden on the user in matching the other party's circumstances when he wants to communicate, and is troublesome and inconvenient for the user. Also, the destination user's usable communication means are not necessarily those that the source user can simultaneously use.
On the other hand, when the destination user does not have the communication means that the source user wants to use, if the destination user does not download the communication means from a communication means provider, communication through that communication means cannot occur. Therefore the source user must use other communication means and ask the destination user to install the desired communication means and have the destination user report completion of the installation. Expanding communication means when one wants to start communicating places a great burden on the user and interferes with smooth communication.
In addition, in recent years there have been many cases in which one user uses a plurality of user terminals and uses a plurality of terminals to suit the user's status. For example, a portable terminal is used while on the go, and different computers are used at the office and home. Under these conditions, even if it is known that a communication means can or cannot be used at one terminal, if the same sort of information is not known for the communication means at another terminal it is difficult to perform communication that takes into account the other party's status.

Communication means notification method and notification system


A preform and container design for a pressurized refillable plastic container, such as a PET carbonated beverage container, having a base section with increased resistance to sprue cracking. Sprue cracking, which may be a problem in warmer climates, is believed to be caused in prior designs by an entrapment of material between the stretch rod tip and the blow mold base during blow molding of the container, which entrapment causes surface defects in the container adjacent the sprue. These surface defects expand during flexing of the container dome, caused by alternating cycles of thermal shrinkage and expansion during container cleaning and filling. Sprue cracking can be reduced by eliminating a depressed dish adjacent the sprue in prior known refillable containers, and may further be reduced by modifications to the preform and container wall thickness ratios and base clearance height.

The first commercially successful refillable PET carbonated beverage container, developed by Continental PET Technologies, Inc. in the 1980's, followed years of failed development attempts by others. The requirements for such a container included resistance to:
caustic stress cracking (due to repeated exposure to caustic cleaning agents at elevated temperatures, followed by repeated exposure to elevated internal pressure upon product filling)
dimensional instability (due to alternating cycles of thermal shrinkage and expansion)
base inversion or creep
drop impact failure
caustic whitening.
Prior development attempts may have satisfied one condition, while aggravating another. Disposable container designs were wholly unacceptable. Still further, a technically acceptable bottle design was required which could be sold at a price competitive with reusable glass containers. Once an acceptable refillable plastic container was found, it quickly eclipsed sales of returnable glass containers due to its light weight and shatter resistance.
Various embodiments of Continental PET's refillable preform and container designs are disclosed in U.S. Pat. Nos. 4,725,464, 4,755,404, 5,066,528, 5,198,248, and numerous foreign counterpart patents around the world.
An additional problem has been found with some refillable PET containers, especially those used in warmer climates--namely cracking around the sprue region of the interior base surface--referred to hereinafter as "sprue cracking." The "sprue" is an extended gate at the tip of the preform; the sprue cracks have occurred in the container around this central gate. Sprue cracking may prevent thorough cleaning of the container (i.e., contaminants may infiltrate the cracks), and/or the cracks may grow and result in a loss of pressurization and leakage of the bottle contents, i.e. a complete bottle failure. In addition, sprue cracking is undesirable because it causes whitening or opacity which is aesthetically undesirable and it also interferes with contaminant inspection, i.e., the inspection machinery considers the whitened or opacified region a contaminant and rejects the bottle.
All commercially-available refillable PET carbonated beverage containers are believed to provide a depression on the inner surface of the container base at the center of the dome, known as a "dish." Many commercial designs also have an external gate (projection) on the outer surface of the preform tip, and an internal dimple (projection) on the inner surface of the preform tip. The reason for the dish, gate and dimple is to ensure centering of the preform in the blow mold base.
Accurate centering is very important with a refillable bottle because it ensures that the standing ring (chime) region of the container base is blown to a uniform thickness. Without such uniformity, there is a tendency for the base to fail due to creep or caustic stress cracking. Thus, to ensure centering the external preform gate is positioned in a receptor (chamber) in the center of the blow mold base, and a dish-shaped opening in the mold base surrounding the receptor serves to guide the gate into the receptor. The internal preform dimple fits within a receptor on the tip of the axial stretch rod, to further ensure centering of the preform in the blow mold base. Still further, in the known processes there is a deliberate pinching (compression) of the preform end cap against the blow mold base, i.e., application of a compressive force, in order to hold the preform firmly in position during blowing and thus ensure accurate centering.
Thus, while the preform end cap has been carefully designed to satisfy the centering requirements, there has now been discovered a problem with sprue cracking for which neither the source nor the solution is known.

Pressurized refill container resistant to sprue cracking


Disclosed is a method of making a photonic crystal using a combination of extruding and drawing techniques. The method is contemplated as being capable of producing both two and three dimensional crystals due to the maturity and diversity of extruding and drawing technology. The method allows the drawing of relatively large photonic crystals and is flexible enough to provide a periodic array of channels or filaments as the crystal features. After the extruding step or steps and before the step of heating and drawing, a plurality of elongated extruded bodies can be bundled and drawn as a unit.

This application claims the benefit of U.S. provisional application No. 60/094,609, filed Jul. 30, 1998.
The invention relates to a method of making photonic crystals and passive components comprising photonic crystals. In particular, the method includes one or more extrusion steps to produce a cellular or channeled object followed by a step of viscously sintering the object. The sintered, channeled object is heated and drawn to a final diameter.
A photonic crystal is a structure having a periodic variation in dielectric constant. The periodic structure may be 1, 2 or 3 dimensional. The photonic crystal allows passage of certain light wavelengths and prevents passage of certain other light wavelengths. Thus the photonic crystals are said to have allowed light wavelength bands and band gaps which define the wavelength bands which are excluded from the crystal.
At present, the wavelengths of interest for telecommunication applications are in the range of about 800 nm to 1800 nm. Of particular interest is the wavelength band in the range of about 1300 nm to 1600 nm.
Light having a wavelength in the band gap may not pass through the photonic crystal. Light having a wavelength in bands above and below the band gap may propagate through the crystal. A photonic crystal exhibits a set of band gaps which are analogous to the solutions of the Bragg scattering equation. The band gaps are determined by the pattern and period of the variation in dielectric constant. Thus the periodic array of variation in dielectric constant acts as a Bragg scatterer of light of certain wavelengths in analogy with the Bragg scattering of x-rays wavelengths by atoms in a lattice.
Introducing defects into the periodic variation of the photonic crystal dielectric constant can alter allowed or non-allowed light wavelengths which can propagate in the crystal. Light which cannot propagate in the photonic crystal but can propagate in the defect region will be trapped in the defect region. Thus, a point defect within the crystal can serve as a localized xe2x80x9clight cavityxe2x80x9d. Analogously, a line defect in the photonic crystal can act as a waveguide for a mode having a wavelength in the band gap, the crystal lattice serving to confine the guided light to the defect line in the crystal. A particular line defect in a three dimensional photonic crystal would act as a waveguide channel, for light wavelengths in the band gap. A review of the structure and function of photonic crystals is found in, xe2x80x9cPhotonic Crystals: putting a new twist on lightxe2x80x9d, Nature, vol. 386, Mar. 13, 1997, pp. 143-149, Joannopoulos et al.
A first order band gap phenomenon is observed when the period of the variation in dielectric constant is of the order of the light wavelength which is to undergo Bragg scattering. Thus, for the wavelengths of interest, i.e., in the range of about 1300 nm to 1600 nm, as set forth above, a first order band gap is achieved when the period of the variation is about 500 nm. However, photonic crystal effects can occur in crystals having dielectric periodicity in the range of about 0.1 xcexcm to 5 xcexcm. A two or three dimensional photonic crystal having even this larger spacial periodicity is difficult to fabricate.
In U.S. Pat. No. 5,774,779, Tuchinskiy, a method of making multi-channeled structures is described. Rods are bundled together and reduced in diameter by extrusion. The step of bundling and extrusion may be repeated using rods which have already been extruded one or more times. However, no step of drawing is disclosed, so that channel density, expressed as number of channels per unit area, is not large enough to produce a photonic crystal.
There is a need for a method of making photonic crystals of two or three dimensions which is repeatable, versatile, and potentially adaptable to a manufacturing environment, as compared to that of a laboratory.
The primary object of the invention is to combine extrusion technology, including the technology of powder extrusion, with glass drawing technology to address the problem of fabricating photonic crystals of all types. The term drawing describes a process in which a viscous body of material is stretched along a pre-selected dimension. To stretch the viscous body without causing tears in the body, the viscosity of the body and drawing tension applied to the body are properly adjusted. The viscosity of the body may be controlled by controlling the temperature of the body. A first aspect of the invention is a method of making a photonic crystal having a band gap. A material comprising at least one glass powder and a binder is extruded through a die to form a body having a first and a second face spaced apart from each other, each face having a plurality of openings. The respective openings in each face are the ends of channels, which extend along the dimension between the two faces.
Suitable glass powders for making the crystal include Pyrex(trademark) and substantially pure silica powder. The extruded body is then heated to drive off the binder at a first temperature and further heated to a higher second temperature to viscously sinter the particulate of the glass powder to form a sintered, extruded glass body. This sintered glass body is further heated and drawn, along the dimension between the two faces, to reduce the diameter of the channels extending between the two channels. The drawn body is referred to as a glass rod or glass fiber having a plurality of channels which extend along the long axis of the fiber or rod. The drawing temperature is typically higher than the sintering temperature, although for certain glass compositions and drawing tensions the drawing temperature may be lower than the sintering temperature.
An optional series of steps may be used if, after extrusion, the body is too large to be accommodated in a drawing furnace. That is, the cross sectional area, taken perpendicular to the dimension between the two faces, of the body and thus the size of the plurality of channels may be reduced by:
filling the channels with a pliable material;
passing the body, in a direction along the channels, through one or a series of reducing dies; and,
removing the pliable material.
This pliable material, which may be a micro-crystalline wax as set forth in Provisional Application No. 60/068230, serves to maintain the channels as the body is passed through one or a series of reducing dies. A reducing die may take the form of a funnel with an entrance opening of dimension commensurate with the cross sectional dimension of the body and an exit opening reduced in size by a factor of 2 or more relative to the entrance opening. After the reducing step, the pliable material is removed
In order for the channeled glass fiber to function as a photonic crystal, the array of channel openings is distributed periodically across the faces of the fiber. For the wavelengths of particular interest at this time in telecommunications, the period of the array of the final drawn fiber or rod is in the range of about 0.4 xcexcm to 5 xcexcm. The novel method disclosed and described herein can produce arrays having periods less than 40 xcexcm, preferably less than 5 xcexcm and most preferably less than 1 xcexcm.
Also, the dielectric constant of the channels must be different from that of the material forming the walls of the channels by a factor of about 3 to provide a useful band gap. For example the channels may be filled with air or evacuated to provide the requisite difference in dielectric constant. As an alternative the channels could be filled with essentially any solid or fluid having the appropriate dielectric constant as compared to that of the glass body.
The required dimensions of a photonic crystal depend upon the intended use thereof. Of particular importance is the crystal area which will be illuminated by a beam of light incident upon the crystal which will propagate through the crystal or a defect in the crystal. The area of the beam may be characterized, for example, by the mode field diameter of the beam. For wavelengths that are at present of greatest interest in optical telecommunications, i.e., those in the range of about 1300 nm to 1600 nm, mode field diameters may be expected to be less than about 10 xcexcm. Thus a reasonable length of photonic crystal measured along the length of the periodic features, is in the range of 3 xcexcm to 12 xcexcm, in the case of side illumination of the crystal.
The area of a plane perpendicular to the length extent of the photonic crystal periodic features can be selected to be in the range of about 100 xcexcm2 to about 1.25 mm2. Larger cross sections are possible using a bundling technique described herein. However, bundling is not well suited to providing uniform periodicity among the elements, such as rods, which make up the bundle. Maintaining common periodicity among the bundled elements is more feasible in the case of rods that can be given an orientation relative to each other which is maintained during heating and drawing. For example square, rectangular, or hexagonal shaped rods can be arranged in a close pack or other pre-selected pattern that will persist through the drawing step.
Such a choice of area is large compared to the light wavelength propagated and allows for line defects in the form of waveguide paths for couplers and splitters. However, it should be understood that the calculation of a band gap in a photonic crystal, or in a photonic crystal having a defect, contains the underlying assumption of a crystal structure essentially infinite in extent. What constitutes a crystal having effectively xe2x80x9cinfinitexe2x80x9d dimensions is a question that must be answered by experiment.
In practice, the length of a photonic crystal made using the method disclosed and described herein is limited on the low end only by the technology available to cut a slice from the drawn glass body. The potential upper limit of length is very large when compared to the length required in optical circuits. The method may reasonably be expected to yield photonic fiber crystals having lengths of the order of tens of centimeters or more.
The glass material to be extruded has a particle size preferably less than about 5 xcexcm. This size provides for good cohesion of the extruded material while allowing for the extruded wall thickness of the channels to be no less than 10 particle diameters, a practical upper limit for both direct particulate extrusion and the optional reduction particulate extrusion. However, larger particle size can be used in cases where a large part of the size reduction is done after the step of viscous sintering, because the particles lose their identities during the sintering step.
Extrusion dies are available which can introduce local or line defects into the elongated body during the extrusion step. Thus a cavity resonator, a waveguide, or a plurality of waveguides may be formed in the extrusion step. It will be understood that the integrity of the extruded body must be maintained during the extrusion steps. Thus in the case of void type defects which pass completely across the face of the photonic crystal, an outermost annular layer, i.e., a cladding layer, must be maintained though the draw step. After the drawing process, a layer designed to preserve the extruded body integrity may be removed by known mechanical or chemical means. If the layer is transparent to signal light, it may remain in place after drawing.
As an alternative, local or line defects can be created in the extruded body prior to drawing removing parts of the wall structure using either mechanical or chemical means. As an alternative, defects can be created by inserting or back-filling channels. If a reduction die extrusion is used, the embedding can be done before or after that step.
A particularly useful photonic crystal component is one having two intersecting waveguide paths. The crystal periodicity is chosen such that light propagating along the line defect, i.e., waveguide in the crystal is in the band gap. Thus, even at a right angle intersection of two waveguide paths the propagating light will make the right angle turn with essentially no loss. The only possible loss is that due to back scattering through the light input port. Here again it should be noted that the statement that the light traverses a bend with essentially no loss contains the tacit assumption of infinite crystal extent.
The method is also adaptable to the making of optical waveguide fibers which have a particular pre-selected channel pattern which extends along the long axis of the waveguide and terminates at the ends of the waveguide. It will be understood that other channel patterns may be found to be useful. For example, channels along the long axis may be intermittent, randomly distributed instead of periodic, or extend over only a few segments of the waveguide length. Also, channels which intersect the long axis, having either a periodic or random pattern, may be found to produce a particular propagation property which is useful in optical waveguide communication systems. Methods for producing channels which intersect the long axis include a piercing step which would be carried out during or after drawing.
An exemplary configuration that is worthy of study is one in which the center portion of the waveguide fiber is a solid glass. The center portion of the waveguide is surrounded by and in contact with a channeled structure which in effect forms the cladding of the waveguide. Such structures have been found to provide waveguide fibers which propagate a single mode over an unusually wide wavelength range. See, for example, Birks et al., xe2x80x9cEndlessly Single Mode Photonic Crystal Fibersxe2x80x9d, Opt. Lett. 22 (13), 961, (1997). The performance of such a waveguide may be expected to change as the number of channels changes, the periodicity changes, or more than one channel size is used. In this latter case, two or more sizes of channels may be used, each of the sizes conforming to a selected periodicity pattern. The making of dies for extrusion of paste or plastic materials is a mature art. The dies required for the line defect, the cavity defect, or the porous cladding in any of its combinations of size and periodicity are known. The dies will therefore not be discussed further here.
For a discussion of the band gap associated with such multiple channel size photonic crystal structures, see, for example, Anderson et al., xe2x80x9cLarger Two Dimensional Photonic Band Gapsxe2x80x9d, Phys. Rev. Letters, V. 77, No.14, p. 2949-2952, Sep. 30, 1996. In this reference, examples of structures which have a band gap and in which the number of different channel sizes is 2 are described.
Another potentially useful embodiment of the method is an optical waveguide fiber that includes a center channel which is surrounded by a periodic array of channels of smaller dimension. The existence of a band gap for such a configuration exists in theory, but has not been verified by experiment. As noted above, the die technology exists for making such extruded bodies for later, size reduction, viscous sintering, and drawing to form a waveguide fiber.
In a second aspect of the invention, the method may be used to produce a plurality of glass rods or tubes as described in the first aspect above. Prior to the step of heating and drawing the glass rods into smaller diameter rods or fibers, two or more rods may be bundled and drawn as a unit. This unit may be drawn in a single step or in drawing and rebundling steps that are repeated until a target size is reached. The resulting elongated object can be:
a xe2x80x9cpolycrystallinexe2x80x9d object, i.e., a cluster of photonic crystals having the same periodicity but not oriented such that the periodicity is maintained from one photonic crystal to the next; or,
a cluster of photonic crystals having more than one periodicity, i.e., more than one set of pass bands and band gaps.
As stated above, depending upon the bundling process and the shape of the bundled rods, the bundling process can produce either type of polycrystalline body or a body comprising a cluster of photonic crystals.
A further aspect of the invention are the photonic crystals which can be made using the methods disclosed and described herein.
Yet another aspect of the invention is a method of making a photonic crystal in which two or more types of glass powder, having different dielectric constants and mixed with one or more appropriate binders, are co-extruded to form an elongated body having a periodic array of filaments of one glass/binder type that extends from one end of the body to the other, separated from each other by walls comprising the other glass/binder type. In the art the glass/binder forming the walls is sometimes referred to as the matrix glass. An alternative method of making the crystal body containing at least two glass types includes backfilling or stuffing the channels formed in an initial extrusion. Following the initial extrusion step, this aspect of the invention makes use of essentially the steps as set forth in the first aspect of the invention.

Method of fabricating photonic structures