A method for generating a cyclic training sequence comprises the following steps: generating randomly the first information block with the length N, copying the last L samples of the first information block to the beginning of the block as the first CP, generating the second information block with the length N by using the first information block of the training symbol in a circle manner in which the last d samples of the first information block are shifted to the position before the rest (N−d) samples and the N samples thus rearranged forms the second information block, copying the last L samples of the second information block to the beginning of the block as the second CP to form the integrated cyclic training sequence.

1. Field of the Invention
The present invention relates to a cyclic training sequence group for uplink/downlink synchronization in the multiuser system, e.g., a Round-Robin training sequence group, and especially relates to a communication system and communication method using the cyclic training sequence group.
2. Description of the Related Art
Currently, there are many classical synchronization algorithms for performing downlink synchronization [1]-[7]. However, uplink synchronization is generally more difficult in the multiuser system, especially when a plurality of users adopt full-multiplexing transmission mode, because in uplink transmission, different users are different distances from the base station, which will introduce different timing offsets with respect to the base station. In addition, different users use different oscillators and the central frequencies of these oscillators may be different; and the moving speeds of different users are different so that different Doppler frequency offsets are formed. The above two reasons lead to users having different carrier frequency offsets with respect to the same base station.
Many classical algorithms utilize the repeated information in the training sequence to perform timing synchronization and carrier frequency offset estimation. At the base station, there will be a phase angle deviation between the repeated information in the training sequence due to the influence of the carrier frequency offset, which can be used to estimate the carrier frequency offset of the user. In the multiuser system adopting full-multiplexing transmission mode, when the training sequences transmitted by different users overlap at the base station, if these training sequences are identical or partially identical in structure, the corresponding phase angle deviation will contain a plurality of users' carrier frequency offset information, i.e., the carrier frequency offset information of a single user will be lost. The interference between training sequences may lead to the failure of the synchronization algorithm of some users.

Cyclic training sequence generating method, communication system and communication method


A complementary metal-oxide semiconductor (CMOS) image sensor and a method for fabricating the same are disclosed. The CMOS image sensor a plurality of photosensitive devices formed on a semiconductor substrate, an interlayer dielectric formed on the photosensitive devices, and a plurality of color filter layers facing into each interlayer dielectric and filtering light for each wavelength, a planarization layer formed on each of the color filter layers, and a micro-lens layer formed on the planarization layer and having a refractive index distribution, in which light is focused to the photosensitive device facing thereto, based on an ion injection profile.

1. Field of the Invention
The present invention relates to an image sensor, and more particularly, to a complementary metal-oxide semiconductor (CMOS) image sensor and a method for fabricating the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for forming a micro-lens by an ion injection process without a reflow process, so as to obtain a desired refractive index distribution, thereby accurately controlling light concentration.
2. Discussion of the Related Art
Generally, an image sensor is a semiconductor device which converts an optical image to an electric signal. There are two kinds of image sensor devices: a charge coupled device (hereinafter referred to as CCD) and a complementary metal-oxide semiconductor (hereinafter referred to as CMOS). The CMOS image sensor includes a photodiode unit which detects irradiated light, and a CMOS logic circuit which processes the electric signal to form data. Moreover, as the amount of light received in the photodiode increases, the photo-sensitivity of the light sensor will increase accordingly.
In order to increase the photo sensitivity, either a fill factor of the photodiode area within the total area of the image sensor needs to be increased, or an optical path of the light irradiated process to the area outside of the photodiode needs to be changed so as to focus light onto the photodiode. The main examples of the light-focusing method would be to form a micro-lens. The related art shows a convex micro-lens formed of a material having an excellent light-transmission ratio is provided on the photodiode. Thus, the optical path of the irradiated light is refracted, so as to irradiate a larger amount of light to the photodiode. In this case, the micro-lens refracts the light being parallel to the optical axis, so as to form a focal point of the light on a specific point of the optical path.
A related art CMOS image sensor and fabrication of a micro-lens thereof will now be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a related art CMOS image sensor. As shown in FIG. 1, the related art CMOS image sensor includes a semiconductor substrate (not shown), a sub layer 11, an interlayer dielectric 12, R, G, and B color filter layers 13, a planarization layer 14, and a micro-lens 15. The sub layer 11 includes at least one photodiode area and metal lines, wherein the photodiode area generates electric charges depending upon the amount of irradiated light. The interlayer dielectric 12 is formed on an upper surface of the sub layer. R, G, and B color filter layers 13 formed on the insulation layer 12 enable light of each specific wavelength to pass through. The planarization layer 14 is formed on the R, G, and B color filter layers 13. And, the micro-lens 15 is formed on the planarization layer 14 and has a convex shape having a set curvature, so that light can pass through the color filter layers 13 facing thereto and that the light is focused onto the photodiode area.
Furthermore, although not shown in the drawings, an optical shielding layer is formed within the interlayer dielectric. The optical shielding layer is formed to prevent light from being irradiated onto an area outside of the photodiode area. Also, the photosensitive device may also be formed to have a structure of a photo-gate, instead of the structure of a photodiode.
Herein, the micro-lens 15 is mainly formed of a polymer group resin by using deposition, patterning, and reflow processes. Additionally, a curvature and thickness of the micro-lens 15 are decided by taking into account various factors, such as the focal point of a focused light. More specifically, the micro-lens 15 should be formed to have optimum size, thickness, and curvature radius, which is decided by the size, position, shape of the unit pixel, the thickness of the photosensitive device, and the height, position, and size of the optical shielding layer.
The most important process in the fabrication process of the micro-lens is a space CD controlling process, in which the space between the lenses is controlled, and also a curvature forming process, in which the optimum curvature of the lens is formed. More specifically, by adequately controlling the curvature of the lens, the optical signal passing through a color filter array is efficiently transmitted to the photosensitive device.
However, the related art CMOS image sensor and method of fabricating same have the following disadvantages. In the related art fabrication method, the CMOS image sensor is fabricated by first forming a rectangular lens array, which is spaced apart by using photoresist layers, and then forming the curvature of the lens by using a reflow process. Thus, it is difficult to provide an adequate space between the lenses. Moreover, when the lenses are not accurately spaced apart from one another, excessive noise may occur during an image processing step, or a sufficient size of the signal may not be provided.
Furthermore, when using the above-described semi-spherical micro-lens, the irradiated light, which is parallel to the optical axis, is refracted from the lens, so as to be transmitted to the photosensitive device facing into the lens, thereby driving the device. However, when light that is not parallel to the optical axis is refracted from the lens, the refracted light may be incorrectly irradiated to a photosensitive device located in a different optical path, thereby causing misoperation. And, finally, the difference in the amount of light being transmitted to the photosensitive device may vary depending upon the type of material and size used to form the lower layer of the micro-lens, thereby reducing light-focusing efficiency and deteriorating image quality.

CMOS image sensor and method for fabricating the same


A magnetic resonance imaging system comprises: a housing providing a medical diagnostic chamber for a subject therewithin lying along an axis. The housing contains: a transmit/receive inductor system having a coil about the axis in proximity with the housing, a gradient inductor system having a coil operatively associated with the transmit/receive inductor system, and a field inductor system having a coil operatively associated with the transmit/receive inductor system. The field coil establishes a supervening field about the entire system. The gradient coil initiates perturbations in the fields and produces signals derived responsively from the perturbations. The transmit/receive coil includes a series of electrical transmission line elements paraxially distributed with respect to the axis about the subject. Each transmission line element includes an outer conductor and an inner conductor spaced radially from the outer conductor relative to the axis. The transmit/receive coil initially transmits to the subject a radio frequency energy field and responsively receives from the subject a magnetic resonance energy field. The signals produced correspond to spatial indicia derived from the subject and are presented as such by a master controller.

1. Field of the Invention
The present invention relates to magnetic resonance imaging and, more particularly, to a high resolution magnetic resonance imaging system and to components thereof.
2. The Prior Art
Magnetic Resonance Imaging (MRI) has proven to be an enormously useful technology both for the detection and diagnosis of human disease as well as for research into the understanding of basic animal physiology. However, current MRI equipment has been limited by achievable signal-to-noise ratio (SNR) and by limitations in the ability to generate homogenous transmit fields for signal excitation, particularly at high magnetic field strengths.
For the acquisition of data from a nuclear magnetic resonance (NMR) signal, four separate components are required. First a static magnetic field must be generated by a permanent magnet generally of the superconducting type. Pursuant to quantum mechanics, the presence of the static magnetic field causes in a subject an energy difference between atomic spins aligned with and against this static magnetic field. The magnitude of the energy difference depends on a variety of factors, including strength of the magnetic field, size of the magnetic moments of individual atomic nuclei, and temperature. In general, a majority of the atomic spins will align with the static magnetic field and a higher energy minority of the atomic spins will align against it. When exposed to an oscillating magnetic field of proper frequency, such as is generated by an alternating current in a radio frequency (RF) coil, some of the lower energy spins aligned with the static magnetic field will be excited to the higher energy state of being aligned against the field. Once the applied transmit RF magnetic field is removed, these excited spins will decay to the lower energy state of alignment with the static magnetic field. During the decay, these spins will generate their own RF magnetic field, which can be electronically detected by the same or a different RF coil and thereby be characterized. In order to determine spatial information about the quantity and properties of the atomic nuclei of the subject, a second set of coils, gradient coils, are used to perturb the static magnetic field. By generating magnetic field gradients, current in this separate set of coils spatially changes the oscillation frequency of the atomic spins by changing the frequency of the nuclear magnetic resonance (NMR) oscillation at appropriate times during transmit and receive, and spatial information regarding the atomic spins can be decoded and converted into an image. The generation and reception of the NMR signal in the RF coil and the currents in the gradient coils are controlled by a computer system which processes the information obtained and displays it on a computer screen or printed film for human interpretation.
The advantages of using NMR are several-fold. First, information can be obtained non-invasively on a wide variety of in vitro and in vivo subjects. The lack of non-ionizing radiation is particularly attractive when images are obtained from human subjects. Second, the properties of the magnetic spins are extremely sensitive to their surrounding chemical environment. This allows a great deal of information to be determined from the magnetic resonance signal, including chemical and molecular structure of a wide variety of materials as well as the chemical and structural characteristics of animal and human tissue. By obtaining spatially dependent information regarding the NMR signal, it is possible to obtain detailed images, which not only show great anatomic detail, but which also depend on the chemical properties of tissue. This provides additional image contrast, allows improved discrimination between healthy and diseased tissue, and permits researchers to obtain previously unavailable information regarding in vivo physiologic function.
Despite the multiple advantages of MRI, one major limiting factor in the usefulness of the NMR machine is the small magnitude of the NMR signal generated by a subject""s nuclei themselves. This weak signal is easily obscured by the noise present in all electronic detection devices. The presence of this noise then limits the maximum achievable resolution or sensitivity of the NMR machine, specifically, its ability to resolve small anatomic details or to characterize time dependent changes in signal intensity, which are important for understanding of a subject""s physiology.
In principle, one can improve the sensitivity of the NMR device by increasing the strength of the static magnetic field. While this does increase signal to noise ratio (SNR), it adds problems in terms of the interaction of high frequency magnetic fields and human tissue, leading to difficulties in achieving uniform image quality and even excitation of NMR spins. Simply increasing the magnetic field strength is a very expensive option: a 3T (3-Tesla) human size magnet costs roughly five times that of a 1.5T magnet. In general, such increased cost places a premium on maximizing SNR at a given field strength.
Most of the noise in human MRI comes from the resistance associated with conductive tissue within the human body. As this resistance is roughly proportional to volume of tissue, large coils, which couple to larger volume of tissue, inherently produce lower quality images than smaller coils. While sensitivity can be improved by making smaller coils, there is a limit to this approach in that eventually the desired body part or region of interest will not fit within the coil or field of view of the coil.
One prior art method designed to increase the field of view of small coils is to use multiple coils arranged in a xe2x80x9cphased arrayxe2x80x9d (U.S. Pat. No. 4,887,039). In this method, the images from each individual coil are processed separately and then combined in such a fashion as to maximize image quality. While this is a useful strategy, it has certain limitations. First the individual coils need to be carefully oriented to minimize their respective coupling. Despite proper orientation, there always will be residual coupling between four or more coils limiting the maximum number of coils and consequently the gains in sensitivity. Furthermore, in the standard geometry feasible with surface coils, this arrangement still produces inhomogeneous images, which can complicate their interpretation for diagnostic purposes.
A second problem is the efficient and uniform excitation of the NMR spins. For most imaging sequences, a homogenous excitation of all spins is required. In general, this requires a larger coil, which then reduces the sensitivity of the system. One commonly used technique is to use a larger coil, optimized for transmit with a second coil specialized for receive. However such systems, as presently implemented, suffer from several disadvantages, particularly when used in high field systems. One disadvantage of current volume transmit coils is the inability to control the field to compensate for variations in patient size and position. While, in principle these variations can be accomplished by manually tuning the coil (see J. Thomas Vaughan, Hoby P. Hetherington, Joe O. Out, Jullie W. Pan, Gerald M. Pohost, xe2x80x9cHigh Frequency Volume Coils for Clinical NMR Imaging and Spectroscopyxe2x80x9d, Magnetic Resonance in Medicine 32:206-218 (1994)) or by using electromechanical relays to switch in additional reactive circuit elements, such methods are time consuming and subject to the variability of mechanical connections.
Conventional MRI coils come in two basic categories. (1) The simpler, the surface coil, consists of one or more conductive loops. Additional reactive circuit components, such as capacitors and inductors, are used to tune the coil and couple energy to or from it to the rest of the NMR system. Importantly, active circuit elements, such as PIN diodes, can be added to allow specialization of coil function for receive or transmit. (2) Volume coils, such as birdcage coils, consist of one or more large surface coils oriented in such a fashion as to produce a homogenous magnetic field. While such coils are in common use, the large size of these coils makes them poor receivers of NMR signal. This difficulty can be overcome by using PIN diodes to xe2x80x9cdetunexe2x80x9d the volume coil for use with a more sensitive surface coil receiver.
In particular, at high fields, the use of volume coils becomes increasing problematic. The large size of these coils required to enclose a useful area of human anatomy, such as the torso or head, leads to them becoming efficient radiators of electromagnetic energy. Moreover, the interaction of large volume coils with tissue at high frequencies leads to non-uniform magnetic fields within human tissue complicating the ability to obtain uniform spin excitation.
The following U.S. Pat. No. 5,557,247 to Vaughn, U.S. Pat. No. 4,751,464 to Bridges, U.S. Pat. No. 4,746,866 to Roschmann and U.S. Pat. No. 4,506,224 to Krause, disclose volume coils based on cavity resonators. Conductive segments within the cavity interact to form a resonant structure. While this coil can offer improved efficiency over a conventional volume coil, several disadvantages exist. First, the structure being closed can give a subject a sense of claustrophobia and make it difficult to present visual stimulation for research purposes. Second, the closed shielded nature of the coil makes it difficult to specialize for the use of transmit or receive purposes. If circuit elements are added to detune the coil, the outer cavity shield will interact with smaller coils placed with the larger cavity, impairing their performance. Additionally, the cavity shield prevents the use of the coil for specialization as a smaller coil to use with receive only function or as its use as a phased array.
The present invention is an improved NMR coil design based on the use of transmission line segments rather than conventional inductive coil elements. The use of transmission lines has several benefits. Transmission lines have a concentration of electromagnetic fields between their elements. By adjusting the distance between these conductive elements, interaction of the magnetic fields of the transmission line with an external sample can be controlled and optimized for NMR signal generation and/or detection. The presence of two conductors also decreases the inductance of each conductor. This minimizes the electric fields associated with the conductors, which is advantageous since these electric fields can be associated with dielectric tissue losses which decrease coil efficiency and sensitivity. Moreover, the inherent shielded nature of transmission lines decreases the radiation of electromagnetic energy from the NMR coil, improving coil efficiency and sensitivity over conventional NMR coil design. The shielded nature of a transmission line also decreases the interaction or coupling between coil elements. This can be advantageous since under proper conditions, coil elements can operate with minimal interaction. This allows a large single coil structure to operate as multiple smaller individual coils. With proper combinations, these separate coils can be combined in such a way to optimize NMR signal generation and/or reception. In particular, by combining signals from individual coil elements, spatial information may be decoded regarding the NMR signal, increasing the sensitivity and speed of data acquisition for both high field and low field NMR systems.
The coil consists of N transmission line segments distributed in a circular, elliptical, or other geometrical arrangement. Each transmission line element is comprised of two or more individual conductors with or without additional lumped or distributed capacitive or inductive circuit components. In general, each transmission line element couples to the others through mutual inductance and capacitive coupling. Additional lumped or distributed inductive or capacitive elements may be placed between the transmission line segments to alter this coupling. The combined influences of the interaction between these elements gives rise to frequency dependent relations between the currents and voltages present on individual transmission line elements. By changing the individual circuit components and transmission line geometry, a given current distribution can be obtained on the transmission line elements at a given frequency. The magnetic field arising from the currents on each element add through superposition and create a given magnetic field configuration for use in either or both the generation and detection of the NMR signal.
In particular, with placement of properly valued reactive components between individual transmission line elements, mutual coupling between elements can be minimized. This allows the resonant structure of the N transmission line segment to become degenerate and allows the currents on each element to be relatively independent. This has the advantage for NMR signal generation in that the currents on each element can be individually controlled at will to generate a excitation field of a desired spatial and phase characteristic. Additionally in such an degenerate mode arrangement, received signals from each element are independent and can then be combined in such a way to optimize image homogeneity, sensitivity, or other desired parameters.
In order for the transmission line structure to be useful, energy needs to be transferred into the coil during signal generation and out of the coil during signal reception. This can be accomplished by inductively or capacitively coupling one or more circuit elements to one or more RF power amplifiers and/or RF receivers. This coupling can be adjusted to allow an arbitrary impedance of such equipment to be matched to the currents and voltages found in the transmission line structure. In particular, the phases of the current in two or more transmission line elements can be offset as to create elliptically polarized magnetic fields for improved efficiency in the generation and/or detection of the nuclear magnetic resonance signal.
In addition to passive components, active circuit elements such as diodes (either regular or PIN) can be added to this structure. With diodes, the tuning of individual transmission line elements or their mutual coupling can be changed in order to modify the current distribution and element impedance of the transmission line segments. When used with one or more additional coils (which may be a combination of transmission line structures or conventional NMR coils), these diodes can be arranged so that during transmit or receive functions, one coil has a desired magnetic field configuration while the other coil presents a high impedance so as not to interfere with the magnetic fields of the first coil. In this manner, each of the two or more coils can be optimized for either transmit or receive, resulting in improved generation and detection of the NMR signal.
Other active circuit elements can be added to the transmission line structure such as vacuum tubes or transistors (including but not limited to conventional bipolar transistors, field effect transistors, gallium arsenide field effect transistors, high electron mobility transistors, pseudomorphic high electron mobility transistors, or heterojunction bipolar transistors). These transistors can be used to provide amplification of either the transmit energy needed in the generation of the nuclear magnetic signal or the small magnitude received energy from the NMR spin decay. In this way, signal losses arising from matching circuits and connecting cables are minimized, leading to improved coil efficiency. If the coil is designed for both transmit and receive functions, diodes may be included to change the coupling between these active amplifier circuits and individual transmission line elements. In this manner, transistors designed for low-noise signal amplification are not damaged by the high element currents during the transmit function and transistors circuits designed for power amplification do not add noise during signal reception.
The addition of active vacuum tube or transistor circuits can provide additional advantages. With proper design, these circuits can present impedance mismatches to the transmission line structure while simultaneously preserving adequate amplifier function. These impedance mismatches can be used to change or minimize coupling between individual transmission line elements, allowing the elements to be decoupled and be relatively independent of each other. During transmit, this has the advantage that individual element currents can be changed electronically in magnitude or phase so as to modify the desired magnetic field for optimal transmit excitation without requiring change or variation of passive circuit elements. This is particularly advantageous at high frequencies where dielectric resonances in human tissue require non-uniform magnetic fields for uniform spin excitation. Additionally, during receive, decoupling of the currents on transmission line elements allows each element to function as a separate signal detector. By combining the signals from these elements electronically, either directly after amplification or at a later stage such as after image reconstruction, these signals can be added in a way such that sensitivity is maximized for one or more areas of interest. In particular, the spatially dependent information from each element can be combined after image reconstruction in such a manner that sensitivity is maximized at each point in an image.
Moreover, the geometric arrangement of the individual transmission line elements can be used to decode spatial information regarding the detected NMR signal. By decoding spatial information from individual coil elements, the steps required for the acquisition of an NMR image can be reduced, allowing the imaging process to be completed in less time.
The illustrated embodiments of the present invention demonstrate an actively decoupled transmission line resonator for use as a transmit coil in conjunction with surface coil receivers, as well as use of a transmission line structure as a receive array coil.
Other objects of the present invention will become apparent in light of the following drawings and detailed description of the invention.

Magnetic resonance imaging system using coils having paraxially distributed transmission line elements with outer and inner conductors


In general, techniques are described to dynamically adjust a session detection time defined by a timer in accordance with a bidirectional forwarding detection (BFD) protocol. The techniques utilize existing hardware and BFD software infrastructure. An example network device includes a memory, programmable processor(s), and a control unit configured to execute a timer, receive one or more packets provided by the BFD protocol, detect, based on the received one or more packets, a congestion condition associated with a link via which the network device is coupled to a network, adjust, based on the detected congestion condition, a session detection time defined by the timer, and in response to a failure to receive a packet provided by the BFD protocol within the session detection time defined by the timer, detect a failure associated with the link.

A computer network is a collection of interconnected computing devices that can exchange data and share resources. In a packet-based network, such as the Internet, the computing devices communicate data by dividing the data into small blocks called packets, which are individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. Dividing the data into packets enables the source device to resend only those individual packets that may be lost during transmission.
Certain devices, referred to as routers, maintain routing information that describes available routes through the network. Each route defines a path between two locations on the network. Upon receiving an incoming packet, the router examines information within the packet and forwards the packet in accordance with the muting information. In order to maintain an accurate representation of a network, routers maintain control-plane peering sessions through which they exchange routing or link state information that reflects the current topology of the network.
Routers typically send periodic packets to each other via the peering sessions to confirm connectivity and to indicate operational status of each device. These periodic packets are sometimes referred to as "keepalives" or "hellos." The routers may use the periodic packets for network liveliness detection, i.e., to detect connectivity status with each other. For example, a router may send periodic packets to a peer router every 50 milliseconds (ms) to indicate that the router is still operational. Likewise, the router may detect reception of corresponding periodic packets from the peer router within the same period of time (e.g., 50 ms). When a packet is not received in the allotted time frame, the router determines that a network event has occurred, such as failure of the peer router or failure of a link or node connecting the two routers. Consequently, the router may update various routing information to redirect network traffic and may issue a number of routing protocol update messages to neighboring routers indicating a topology change.
As one example, routers may exchange periodic packets by establishing a session provided by the bidirectional forwarding detection (BFD) protocol. In accordance with BFD, a first router periodically sends BFD packets at a negotiated transmission time interval and detects a connectivity failure when the router does not receive a BFD packet from a second router within session detection time interval. The transmission time interval for BFD may be negotiated by the routers. The BFD session detection time interval is not negotiated. Instead, each receiving router independently calculates BFD session detection interval based on the negotiated transmit interval and a detection multiplier statically configured for that router. For instance, a router may negotiate to receive BFD packets every 50 ms from a peer router and may independently utilize a detection multiplier of three (3) times that interval, i.e., 150 ms in this example, for detecting failure. If the receiving router does not, receive a. BFD packet from the peer router within the 150 ms session detection time interval, the receiving router detects a connectivity failure with respect to the second router. Consequently, the receiving router may update its routing information to route traffic around the second router. Further details of the BFD protocol may be found in the proposed standard for RFD, by D. Katz and D. Ward (Juniper Networks, June 2010, ISSN: 2070-1721), the entire content of which is incorporated herein by reference.

Dynamically adjusting liveliness detection intervals for periodic network communications


Container filler apparatus having a bowl for receiving liquid and for dispensing the liquid into a multiple of containers, a plurality of liquid-outlet lower openings and collars depending from the bowl, a plurality of liquid-outlet control valve mechanisms cooperatively interfitted within respective ones of the collars, a distortable retainer spring between each valve mechanism and its respective collar for retaining the valve in its collar, and safety clips exterior of said bowl engaged between the valves and their respective collars whereby each said valve mechanism can be removed from the bowl solely at the exterior of the bowl by removing the safety clip and pulling the valve down a sufficient amount to release the retainer spring. The retainer spring is an annular canted coil spring. An annular seal is between each valve mechanism and its respective collar, adjacent to but spaced from the canted coil spring.

This invention relates to container filler apparatus, particularly apparatus for filling consecutive containers with flowable material, typically liquid, especially edible liquids such as milk, juice, water and the like.
Apparatuses of this type have a large filler bowl containing a quantity of liquid capable of filling many advanced containers such as bottles. Typically the bowl possesses a substantial number of underside depending valves per machine, usually ranging between 1 and 100 valves. These valves must be removed from the bowl fairly often for cleaning, maintenance and inspection, especially if dispensing dairy products and/or if changing from one type and/or flavor of product to another type and/or flavor of product. In fact, the dairy industry may remove the valves one or more times per day for cleaning and inspection, followed by replacement of the valves. To remove, clean and replace these valves on currently available filler apparatuses is a substantial time and labor consuming operation. The valves must be individually disconnected at the inside of the large bowl. Specifically, all current machines in the industry require removal of an internal retainer at the inside bottom of the filler bowl for each valve, to allow removal of the valve from the filling machine. To perform this removal, the bowl must first be emptied of product, and the bowl lid or cover removed or lifted to allow access to the valve internal retainers. The machine operator must then reach down inside the bowl and remove each valve retainer as the operator or another person holds the valve assembly from the outside of the bowl to prevent the valve from falling out of the machine. Since gravity fillers often have anywhere from 6 to 56 valves per machine as noted, this process of valve removal for all the valves is cumbersome and time consuming, but the filling industry has accepted it for years for lack of an alternative.
To reinstall valves in the presently available machines, the valve assemblies must be inserted up through the filler bowl, and then rest the valve on the machine lifter. The operator then has to climb up and reach into the filler bowl, pull the valve assembly further into place and lock it in place with the internal retainer, all from the inside of the bowl. The bowl cover or lid is then placed back on the bowl. When the bowl lid or cover is lifted or removed, the bowl must be resanitized prior to filling with product.

Container filler apparatus external disconnect valve


A saddle clamp assembly includes a hollow cylindrical body centered about a longitudinal axis and being diametrically split into semicircular top and bottom sections each having a pair of radially outwardly projecting connection flanges at their opposite ends. A pair of bolts are captively retained on the top section flanges and are threadable into nuts captively retained on the bottom section flanges. A base member is anchored to a central underside portion of the bottom clamp body section and has a pair of connection tabs positioned beneath the bottom clamp body section connection flanges on opposite sides of the clamp axis. A pair of bolts are captively retained on the base member connection tabs and are threadable into a pair of nuts captively retainable on a support structure. The connection tab and connection flanges on each side of the clamp body are axially offset in a manner permitting downward installation/removal tool access to the lower bolts past the connection flanges. An elongated retention tether is used to connect the top clamp body section to the balance of the clamp assembly to prevent loss of the top clamp body section when it is removed from the bottom clamp body section.

1. Field of the Invention
The present invention generally relates to equipment support and mounting apparatus, and more particularly relates to saddle clamp structures used to secure elongated tubing runs, wire bundles and the like to a support surface.
2. Description of Related Art
Devices commonly referred to as saddle clamps are conventionally utilized to firmly but removably secure longitudinally spaced apart sections of tubing runs, wire bundles and other elongated objects to suitable support structures to prevent undesirable lateral deflection of the elongated object. In a conventional configuration thereof, a saddle clamp typically comprises an elongated, plate-like arcuate body portion having connection tabs extending outwardly from its opposite ends, lying generally in a common plane, and having mounting holes extending therethrough.
To removably secure a given section of the elongated object to, for example, a plate-like support structure, the object section is positioned between two spaced apart mounting holes formed in the support structure, the clamp body is placed over the object section in a manner aligning the connecting tab holes with the support structure holes, a pair of bolts are extended through the aligned pairs of connecting tab and support structure holes, and suitable washers and nuts are placed on the bolts to secure them in place.
While simple in construction and theoretically easy to use, conventionally configured saddle clamps of this general type are subject to a variety of well known problems, limitations and disadvantages. For example, particularly in congested or limited access areas they can be difficult to install and remove without dropping, and possibly losing, their separate nut, bolt and washer components.
Additionally, when these conventionally configured saddle clamps are used to hold spaced apart sections of tubing runs, realignment of the tubing run (once one or more of the clamps have been removed) can be difficult, if not impossible, since removal of the clamp body easily permits its previously secured tubing run section to laterally deflect. When the clamp is to be reattached, it is often very difficult to move the freed pipe run section back into place, realign the clamp body and support structure mounting holes, and then reinstall the bolts, washers and nuts.
It can be readily be seen from the foregoing that it would be desirable to provide an improved saddle clamp that eliminated, or at substantially reduced the foregoing problems, limitations and disadvantages typically associated with conventionally configured saddle clamps of the general type previously described herein. It is accordingly an object of the present invention to provide such an improved saddle clamp.

The United States of America as represented by the Administrator of the National Aeronautics and Space Adminstration


A chirp switching circuit comprises a Mach-Zehnder modulator having a Y-branched part for branching an incoming optical signal into first and second optical signals and an X-branched part merging the first and second optical signals with each other, the Mach-Zehnder modulator causing phase modulation in the first and second optical signals by a modulation signal, and a directional coupling optical switch that switches first and second optical output signals output from the X-branched part of the Mach-Zehnder modulator by merging the first and second output optical signals in response to a chirp switching control signal.

The present invention relates to chirp switching circuits and optical transmission systems and more particularly to a chirp switching circuit for switching transmission chirp and an optical transmission system that uses such a chirp switching circuit.
In view of the needs of increasing transmission capacity, technical development is being undertaken with regard to optical transmission systems in the directions of achieving: higher transmission speed (increase of bit rate); wavelength multiplexing for enabling transmission of plural signals via a single optical fiber at different wavelengths; and increase of transmission distance.
With increase in the transmission speed, there occurs a distortion of signal waveform in the optical signals transmitted through an optical transmission path because of spreading of the spectrum of the optical signals resulting from signal modulation and further from the dispersion pertinent to the signal transmission path. Such distortion of the signal waveform limits the distance that the signal can be transmitted. This distortion of transmitted signal waveform depends upon the mutual relationship between the chirp (time-dependent wavelength shift) that is pertinent to the transmission part and the chirp caused by the dispersion of the transmission path and non-linearity of the transmission path.
In a Mach-Zehnder (MZ) modulator, it is possible to adjust the chirp (time-dependent wavelength shift) of the transmitter output by changing the ratio of phase modulation between the waveguides of two directions. The chirp caused by the transmitter induces a pulse compression or decompression in cooperation with dispersion and chirp of the transmission path, and thus, it is possible to relax the foregoing constraint imposed upon the transmission path length because of dispersion, by suitably choosing a transmission output chirp according to the transmission path condition.
Meanwhile, there arises a situation in which it is desired to switch the chirp of the Mach-Zehnder modulator, as in the case of switching the signal path from the current path to a path where the transmission path conduction such as transmission distance is different. FIGS. 1A and 1B show such an example of switching the signal path from a current (work) path to a reserve (protection) path in an optical transmission system of ring structure.
Referring to FIGS. 1A and 1B, the optical transmission system is constructed by nodes 10a-10f connected in the form of a ring, wherein each of the nodes 10a-10f achieves optical amplification and compensation of dispersion. Thus, when an optical signal is to be transmitted from a transmission part 11 to a receiving part 12, the node 10b usually chooses a current path A that reaches the node 10b from the node 10a in a clockwise direction as shown in FIG. 1A.
On the other hand, when there occurs a failure in the optical transmission path between the nodes 10a and 10b, the transmission path is switched to a reserve path B that reaches from the node 10a to the node 10d in the anti-clockwise direction via the nodes 10f, 10e, 10d and 10c.
Here, let us assume that the path A has a negative residual dispersion and the path B has a positive residual dispersion.
As can be seen from FIG. 3 that shows the relationship between the residual dispersion and the sign of the chirp, use of positive chirp is suited in the case there is a negative residual chirp, while in the case the residual dispersion is positive, it is suitable to use a negative chirp. Thus, when there is a need to switch the transmission path from the path A to the path B, there is a need of switching the transmission chirp from positive to negative.
FIG. 4 shows an example of the chirp switching circuit that uses a conventional Mach-Zehnder optical modulator.
Referring to FIG. 4, the Mach-Zehnder optical modulator divides the light coming in from an optical source 15 into two, different optical waveguides 17 and 18 at a Y-branching part 16, wherein the respective lights undergo phase change in the optical waveguides 17 and 18 and are merged again at a Y-branched part 19. Thereby, On/Off control is achieved for the optical signal based on the phase difference thus induced.
FIG. 5A shows input/output characteristics of the chirp switching circuit that uses such a Mach-Zehnder optical modulator, while FIGS. 5B-5F show input/output signal waveforms of the chirp switching circuit.
In the Mach-Zehnder modulator, the logic value of an input signal (electric signal) shown in FIG. 5B is inverted by a high-speed driver circuit 21 and the operational point of the Mach-Zehnder modulator is shifted by an operational point stabilization circuit 22 at the same time. With this, there is caused inversion in the transmission chirp. It should be noted that FIG. 5B shows the optical intensity in the optical waveguide 17 while FIG. 5C shows the optical intensity in the optical waveguide 18. Further, FIG. 5D shows the phase of the output optical signal while FIG. 5F shows the chirp caused in the output optical signal.
Because the optical amplifier in each of the nodes 10a-10f has a time-dependence in the response characteristics thereof, there occurs a change of output when there is caused a change in the input, wherein there are cases in which such a change is accumulated. It should be noted that such accumulated change of optical signals may cause overload or even damage in the optical components at the reception side or at the intermediate position on the signal transmission path. Thus, in the case there is provided optical amplifiers in the transmission path and in the case there is going to be made switching of chirp in correspondence to the switching of transmission path from the current transmission path to a transmission path of different path condition, it is desired that the change of optical output caused with the switching of chirp is suppressed as much as possible.
Parent Reference 1 teaches the technology of obtaining a chirped optical signal of inverted polarity by changing the operational point of the Mach-Zehnder optical modulator in correspondence to the chirp polarity.
PATENT REFERENCE 1 Japanese Laid-Open Patent Application 11-266200

Chirp switching circuit and optical transmission system


A cosmetics brush, and more particularly, to a cosmetics brush in which cosmetics liquid is discharged to a brush using the air pressure generated by pressing an inner body is provided. In the cosmetics brush, the lower part of the inner body whose upper part is thread coupled by a coupler and that includes a sealing ring in the inside thereof is pressed so that the cosmetics liquid stored in the inner body is discharged to the brush through liquid guiding passages and a discharge hole formed in a discharger and a liquid transporting tube due to the air pressure generated while the inner body ascends and descends to let a user apply make-up. Since the inner body thread coupled with the coupler can be separated and refilled with cosmetics liquid when cosmetics liquid is exhausted, the cosmetics brush is economical and convenient.

1. Field of the Invention
The present invention relates to a cosmetics brush, and more particularly, to a cosmetics brush to which cosmetics liquid is discharged using air pressure generated by pressing an inner body. The lower part of the inner body whose upper part is thread coupled by a coupler and that includes a sealing ring in the inside thereof is pressed so that the cosmetics liquid stored in the inner body is discharged to the brush through liquid guiding passages and a discharge hole formed in a discharger and a liquid transporting tube due to the air pressure generated while the inner body ascends and descends to let a user apply make-up. The inner body thread coupled by the coupler can be separated when cosmetics liquid is exhausted so that the inner body is refilled. Therefore, it is possible to easily refill the inner body with cosmetics liquid and to easily assemble the inner body.
The number of parts that constitute the cosmetics brush is small so that it is possible to easily assemble the cosmetics brush. The inner body is assembled in package units of two parts to be supplied to a company before filling the inner body with cosmetics liquid so that it is possible to easily fill the inner body with cosmetics liquid and to easily assemble a container.
2. Discussion of Related Art
A cosmetics liquid filled cosmetics brush in which cosmetics liquid and cosmetics goods used for applying the cosmetics liquid are integrated with each other is know.
However, since the conventional cosmetics brush is composed of independent parts that are connected to each other, the number of parts that constitute the cosmetics brush is large so that manufacturing expenses increase. In particular, when the independent parts are connected to each other, it is difficult to keep the parts tightly sealed up so that it is difficult to reduce a defective proportion to no more than a predetermined level.
Also, since the number of parts that constitute the cosmetics brush is so large that assembling and manufacturing processes are complicated and that the parts assembled in minimum package units are assembled in package units of no less than four parts to be supplied to a company before filling cosmetics liquid, the number of parts to be assembled after filling the cosmetics liquid is large so that assembling processes are complicated.


A mounting structure for mounting a steer-by-wire vehicle steering apparatus on a vehicle body side, comprising: a housing for rotatably retaining therein one end of a steering shaft of the steering apparatus, while retaining therein an actuator for exerting reactive force in order to impart reactive force in response to turning of an operating member fastened to an other end of the steering shaft that projects from the housing and rotatable together with the steering shaft; and a plurality of mounting portions disposed about a turning axis of the operating member so as to extend diametrically outwardly, the mounting portions fastened at respective fastener portions thereof to a vehicle body side at multiple locations, at least one of the fastener portions of the mounting portions is fastened to the body side via a rubber elastic body so that the housing is elastically supported on the body side.

1. Field of the Invention
The present invention relates to a steering apparatus for use in a vehicle, which apparatus employs a "steer-by-wire" system in which mechanical linkages between wheels and control components for controlling the wheels in a vehicle are replaced with electrical signals. The present invention is also relates to a mounting structure for mounting the apparatus on the vehicle.
2. Description of the Related Art
Conventional steering mechanisms developed and tested to date include those incorporating steer-by-wire technology, such as the mechanism described in non-patent Citation (Sumio Motoyama, "Steer-by-wire and Vehicle Motion Control" Jidosha Gijutsu Kai, February 2003, Vol. 57, pp. 39–43), for example. The greatest concern regarding such systems is how to ensure reliability in the event of system malfunction. A number of types have been proposed, such as one that switches over to conventional mechanical linkage in the event of a system malfunction, or one equipped with a backup actuator. In JP-A-2001-213342, JP-A-2003-137124 and JP-A-2003-165460, for example, these have been disclosed steering apparatus of various kinds employing steer-by-wire systems.
Each of these implementations of steer-by-wire technology has the advantage that by replacing steering control with electrical signals, it is relatively easy to make the devices compatible with ITS (Intelligent Traffic Systems), which dramatically expand controllability of maneuver stability control of vehicles. Additionally, eliminating mechanical linkages between steering control components and the wheels has the promise of reducing direct transmission of vibration from the wheels and engine.
However, the steering wheel or other control component that transmits the intention of the driver must be fastened to and supported by the vehicle body side, and thus in the same way as before, input load from power train components and the road surface as well as vibration amplified by various kinds of resonance systems belonging to the vehicle body side are transmitted from fastener portions to the control component, creating an unpleasant feeling for the driver.

Vehicle steering apparatus and mounting structure for mounting the apparatus on vehicle


An system and method to automatically disconnect a retrofit electrical unit from an electrical system in the event of an emergency situation and maintain power to the retrofit electrical unit.

1. Field of the Invention
The present general inventive concept relates to system power switching and, more particularly, to system and method of switching power provided to an electronic aircraft system.
2. Description of the Related Art
Aircrafts utilize a combination of mechanical and electrically based instrumentation to convey the state of the aircraft to the pilot or flight crew. Mechanically based instruments typically use fluid pressure, such as air, oil, and fuel, to cause deflections in needles located within instrument housings located in the cockpit to indicate the corresponding state of a system on the aircraft. Electrically based instruments typically use solid-state sensors to convert mechanical forces into electrical signals, which can then be displayed on various types of equipment located within the cockpit.
Aircraft also make extensive use of electronic instrumentation systems for purposes of navigation, communication, and surveillance.
Smaller, lighter aircraft types, which are typically referred to as "general aviation aircraft", have electrically based systems are typically powered by a 14 or 28 volt direct current ("DC") power source. These power systems typically include a battery, a power generation mechanism attached to the aircraft's engine(s), and a voltage regulator. Energy provided by the running engine is used to both power electrical devices on the aircraft and maintain the charged state of the battery. When the engine is not running, energy is obtained solely from the battery. The regulator is used to maintain a constant voltage level regardless of the engine speed. A single, sealed lead-acid battery, a regulator, and an automotive style alternator is a commonly employed configuration.
The alternator functions by converting mechanical energy created by the engine into electrical energy by spinning the shaft on the alternator, which creates electrical power by inducing voltages and currents into coil windings. During normal engine operation, this electrical power is regulated to a voltage such as 13.2 to 14.4 volts, which is slightly higher than the normal quiescent voltage of a lead acid battery. This elevated voltage level is sufficient to charge the lead acid battery. When this charge voltage is removed. i.e. the engine stops or the alternator fails, the lead acid battery voltage returns to a slightly lower voltage such as 12.6 to 12.8 volts.
Because the battery is directly tied to the overall electrical supply system for the aircraft, the voltage of the overall electrical system of the aircraft directly reflects whether the alternator is actively capable of generating power based entirely on the voltage of the aircraft's electrical system. This voltage can be used as an indicator of the aircraft's electrical system health, and indicate whether a failure has occurred.
Because of the relatively high energy density requirements and the mechanical nature of the engine and alternator, aircraft with this type of electrical system are highly susceptible to loss of electrical generation ability. Wiring, alternator, and regulator failures are a fairly regular occurrence in general aviation aircraft. This is especially true for older aircraft that are retrofitted with additional electrically based avionics that place an additional strain on very old electrical components.
For single engine aircraft, loss of the one engine is also sufficient to cause loss of electrical generation capability. For twin engine aircraft, loss of both engines is typically required for loss of electrical generation capability. In multiple engine aircraft, loss of electrical generation capability is typically related to common-mode failures, and may occur due to fuel starvation, fuel contamination, or other factors. Some aircraft support an air-driven electrical generator, but this configuration is not common given the additional weight, cost, and complexity of these systems.
When power generation capability is lost, the aircraft's electrically based systems must be powered solely from the aircraft's battery. When this occurs, it is a common practice to reduce or shut down power to or "load-shed" non required systems. This is implemented by turning off such systems such as entertainment equipment and other non-essential loads such as cabin lights, and air conditioning. Items that are required for the continued safe flight and landing of the aircraft are considered "essential loads" and cannot be turned off under these circumstances.
The objective of the load-shedding exercise is to reduce the overall power consumption of the aircraft such that essential loads or critical systems can continue to operate until such time that the aircraft can be safely landed. Thirty (30) minutes is industry-accepted minimum time period for general aviation aircraft. To achieve this time objective, the aircraft manufacturer must design the capacity of the electrical charge system, battery size, and wiring in consideration of the required loads for a given avionics system installed on the aircraft.
The architecture of these aircraft systems makes it more difficult to add electrically based equipment to the aircraft, and a new load analysis must be performed to ensure that adequate battery power reserve is still provided as each new piece of equipment is added. Performing a load analysis is very difficult and time consuming. It may also result in the requirement to increase the size of the battery, which may increase the size, cost, and weight of related components.
Modification of the battery may be required especially in the scenario where essential systems that are electrical in nature are being added. This is typically encountered when a mechanical instrument is being replaced by its electrical equivalent. In this scenario, an additional electrical load is being added to the aircraft, but for a piece of equipment that cannot be load-shed as it is an essential instrument. The replacement of the primary mechanically based attitude, airspeed, and altimeter with an electronic equivalent is an example of this scenario.
Accordingly, there is a demand for a system that allows for the replacement of essential and/or non-essential mechanically based instrumentation with more modern electronically based equipment without effecting the safety margins designed into an aircraft's electrical power generation system, and does not require a new load analysis, upgrading of the aircrafts electrical system, or provisioning for a larger battery.

Airborne power system disconnect system and method


A WLAN baseband chip and an FDMA PPDU generation method are disclosed. The WLAN baseband chip obtains a subcarrier coefficient corresponding to a subcarrier set, m LDR SYNC sequences, and n−m HDR SYNC sequences. The WLAN baseband chip performs duplicating processing on m data streams in n data streams, to obtain m data sequences on which the duplicating processing has been performed and n−m remaining data streams. The WLAN baseband chip obtains m pieces of to-be-modulated data based on the m LDR SYNC sequences and the m data sequences on which the duplicating processing has been performed, and obtains n−m pieces of to-be-modulated data based on the n−m HDR SYNC sequences and the n−m remaining data streams, to obtain n pieces of to-be-modulated data. The WLAN baseband chip performs postprocessing to obtain a frequency-domain symbol sequence, to obtain an FDMA PPDU.

Institute of electrical and electronics engineers (IEEE) 802.11 is a series of wireless local area network (WLAN) communications standards. The IEEE 802.11 supports two types of physical layer frames. The two types of frames include a frequency division multiple access (FDMA) physical layer convergence procedure protocol data unit (PPDU). The FDMA PPDU includes a plurality of sub PPDUs, and each sub PPDU corresponds to one WLAN device. A network device may send an FDMA PPDU, to communicate, through FDMA, with a plurality of WLAN devices having a wake-up radio (WUR) receiver. The FDMA essentially is multiple access connection implemented by using a frequency division method, to divide a total bandwidth of a transmission channel into several orthogonal sub-channels. Each WLAN device occupies one sub-channel, and one sub-channel corresponds to one sub PPDU. WUR is a WLAN energy-efficient mechanism defined in IEEE 802.11ba. A new physical layer format is introduced into the WUR. A WUR frame has a high data rate (HDR) mode or a low data rate (LDR) mode.
A current method for generating, by a network device, a WUR frame in a form of an FDMA PPDU includes: The network device stores an On-WG time-domain symbol whose length is two microseconds (μs) (a 2 μs On-WG time-domain symbol) and an On-WG time-domain symbol whose length is 4 μs (a 4 μs On-WG time-domain symbol) that correspond to different communicable WLAN devices. The network device first determines, based on an HDR mode or an LDR mode configured for a sub PPDU corresponding to a WLAN device, to use a 2 μs On-WG time-domain symbol or a 4 μs On-WG time-domain symbol in a time-domain symbol corresponding to the WLAN device to perform on off keying (OOK) modulation processing, to obtain a modulated symbol corresponding to each WLAN device. Then, the WLAN device obtains an FDMA PPDU based on the modulated symbol. In other words, currently, the network device performs OOK modulation processing for each WLAN device based on a time-domain symbol, and then obtains an FDMA PPDU based on a modulated symbol. A current process of generating, by the network device, an FDMA PPDU is: performing processing separately for different WLAN devices in time domain, namely, "distinguishing between" a plurality of users in time domain.
However, a common WLAN chip performs processing for different WLAN devices in frequency domain, namely, "distinguishes between" a plurality of users in frequency domain.

WLAN baseband chip and FDMA PPDU generation method


A method for forming an angled plastic article of varying density whereby a blowing agent is added to a plastic material and the material is injected into a mold cavity of a mold unit. The interior walls of the mold cavity are maintained at a temperature sufficient to prevent the outer skin of the hardening plastic article from producing gas bubbles. The volume of the mold cavity is increased to allow bubbles to produce and uniformly distribute themselves throughout the mold cavity and then a reconversion phase is instituted whereby the desired density of the finished plastic article is achieved without voids or aberrations appearing in the surface of the plastic article. The mold unit is provided with extensible beveled edges which extend and retract as the mold cavity is enlarged and compressed. By this method, a resulting plastic article of varying density is produced having grooves running the length of the article. After the molding process is complete, an adhesive is applied to the grooves and the molded article is bent whereafter the adhesive maintains the article in the angled orientation. By this method, a complex structure having a smooth outer skin and a lightweight interior may be produced quickly and efficiently.

This invention relates to a method for forming an angled plastic article of varying density and, more particularly, to a method for molding and bending a plastic article to form a smooth dense outer shell and a rare interior.
Injection molding machines generally include a two-section mold unit wherein one of the mold sections is stationary and includes an end gate opening for the injection of mold material into a mold cavity formed by the two mold sections. The other mold section is generally movable between an open position away from the stationary mold section and a closed position wherein the two mold sections are in sealed contact engagement to form the mold cavity. Once the mold cavity has been formed, a screw or similar injection device is used to inject a plastic material into the mold cavity where the material is cured under pressure. Injection molding provides an efficient means for producing plastic articles both quickly and economically.
It is often desired to create a plastic article of a decreased density which reduces the amount of material required to make the part and which significantly decreases the weight of the part. One way of creating a plastic part of reduced density is through the use of a blowing agent. Blowing agents are well-known in the art with most blowing agents being heat-activated. When mixed with a plastic material under controlled conditions these blowing agents produce bubbles. If a blowing agent is evenly distributed throughout the plastic material the bubbles are generally trapped evenly throughout the plastic article as the article cures. These trapped bubbles form a cellular structure within the finished article.
While it is often desirable to have a cellular structure within a plastic article, this cellular structure is typically undesirable on the outer shell of a finished plastic article. Bubbles forming near the outer shell of a curing plastic article often result in unaesthetic holes appearing on the surface of the article. Such surface bubbles may also compromise the integrity of the surface by creating sink holes or weak points where the article is unable to sustain pressure.
As described in co-pending U.S. patent application Ser. No. 08/082,266, now U.S. Pat. No. 5,437,823 it is desirable to mold a plastic part with a uniform cellular structure on the interior, which allows the part to be molded lighter and with less material, while at the same time having a denser outer skin, which increases the aesthetic and structural aspects of the finished article. To mold a plastic article without surface defects, the co-pending application describes a process whereby a two-section mold unit is filled with a plastic injection material having a blowing agent incorporated therein. As the injection material contacts the cool sides of the mold unit, the blowing agent is deactivated and the material near the sides of the mold cavity hardens into a smooth exterior. The warm interior of the material, however, has a cellular structure caused by the heat activation of the blowing agent within the injection mixture.
Because an article produced by the above process produces a lightweight article with a smooth aesthetic exterior appearance, it would be desirable to produce large containers and other objects which could benefit from the weight decrease of the interior cellular structure. Given that this process requires that the mold units move in relationship to one another during the molding process, the process is very well suited for producing flat sheets of material. While it is possible to produce more complex shapes with the above process, the mold units for producing such articles would necessarily be larger and more complicated owing to the requirements of moving the mold sections in relationship to one another during the molding process.
Another difficulty associated with molding a plastic article with a rare cellular interior and a smooth plastic exterior is the difficulty in maintaining an exterior skin of a constant thickness around corners in the mold cavity. Typically, in a molding process, the increased cooling effect of the mold cavity at places where two sides of the mold cavity meet leads to a thicker skin being formed at that point. This added thickness not only increases the amount of material which must be added to the mold cavity, thereby increasing costs, but the increased thickness also adds additional weight to the finished plastic article. Additionally, because the necessity of moving the mold sections in relationship to one another, and due to the limitations of mold cavity shape in plastic injection processes, it has not been possible to mold certain shapes with a cellular interior and smooth exterior. It would therefore be desirable to mold a flat sheet which could then be transformed after molding into a more complex shape.
The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention.

Method for forming an angled plastic article of varying density


The ferry boat has a rectangular main deck with superstructure above and hull structure below. The superstructure is essentially rectangular in all views and has one or more decks with a plurality of traffic lanes on each deck in addition to those on the main decks with optional passenger carrying compartments. The lanes are straight and parallel and there are no deck-to deck ramps. The hull structure has two sidewalls, one along each of the long sides of the main deck and two skirts, one at each end of the main deck. The skirts extend between the sidewalls and have vertical aft surfaces and front surfaces which slope downward and aft. The lower extremities of the sidewalls are further from the main deck than the apexes of the skirts. The volume enclosed by the sidewalls, skirts, main deck and water surface is filled with entrapped air which will compress to provide a major part of the support of the boat. There are two hydrofoils, one forward, one aft and extending between the sidewalls. Each foil is supported from the deck structure by several struts. The struts and foils have blunt trailing edges ventilated by air ducted down the struts. The foils are submerged about one chord length below the lower edges of the sidewall and the lower edges extend below the apexes of the dams.

There is well known prior art in all the fields cited above, including ferry boats having multiple decks with a plurality of lanes on each deck.
The patents listed below are a sampling of the prior art:
U.S. Pat. Nos. 1,799,456 2,672,840 3,742,888 4,008,675 4,227,475 4,196,686 4,422,517 4,766,829 5,146,863 5,415,120 PA1 Japan 60-163788 PA1 Soviet Union SU-532-548 PA1 British 895-341
U.S. Pat. No. 3,590,762 issued to Yuan discloses a land and water based vehicle equipped with hydro/air foils generally oval in shape with slotted trailing edges for jet flow therefrom and for circulation control of the flow around the foil to impart high lift to the foil for controlling the vehicle without the necessity for changing the angle of attack of the foil.
U.S. Pat. No. 3,742,888 issued to Crowley discloses a soft riding-stable multiple-chamber air cushioned boat hull having a plurality of high pressure air chambers around the periphery automatically providing heave stability as well as roll and pitch stability. The hull may further include a vent slot proving a means for exhausting the spill out of the continuously charged high pressure chambers and further makes a sharp reduction in the bow wave pressure. In addition to providing stability the high pressure chambers lift the boat providing a low friction, soft riding air cushioned support.
U.S. Pat. No. 3,968,762 issued to Meyer, Jr. teaches a water craft combining the physical and hydrodynamic features of a catamaran, hydrofoil and rigid sidewall air cushioned vehicle. The water craft is intended to operate as a multi-modal vehicle in the approximate speed range of 0-100 knots. The vehicle from at rest to operational speed, obtains its lift at first from 100% buoyancy of catamaran hulls, then from dynamic lift of hydrofoils, and finally from powered aerostatic lift from a captured air cushion. A combination of two or all lift modes may be used through speed changes and at intermediate speeds.
U.S. Pat. No. 4,008,675 issued to Johansson discloses a ship comprising a hull in which vehicles can be readily loaded and unloaded from at least two ramps at about the same level, the ramps communicating with a cargo-carrying portion extending through two decks and comprising fully separated cargo volumes, in which straight blind alleys emanating from lobbies within the hull at opposite ends of the hull communicate with mutually inclined decks extending upwardly and downwardly forward-aft and aft-forward, respectively, and in communication with respective opposite lobbies.
U.S. Pat. No. 4,196,686 issued to Moran teaches a sidewall drag reduction system for captured air bubble type surface effect ships having rigid surface-piercing sidewalls. Pressurized air is discharged vertically down into the surface effect ship air cushion chamber from platform ports, and horizontally into the air cushion chamber from nozzles located near the bottom of the internal surface of the sidewalls.
U.S. Pat. No. 4,422,517 issued to Hammerschlag discloses bow and stern seals for sidewall type air cushion vehicles for contacting , together with the sidewalls, the air cushion under the vehicle. They consist of a substantial number of more or less equidistant rods connected by flexible membranes, these rods being designed to hinge around a more or less common axis at substantially the top of the air cushion, the rods extending beyond their hinge points and being positioned by two sets of opposing air bags, one set of air bags acting on the extensions of the rods above the hinge points and the other set on the sections of the rods just below the hinge points. The membranes are attached with a large amount of slack so that the rods can rotate a very substantial amount relative to each other. As the air bags will allow the rods only to rotate a limited amount relative to each other, the membranes will not get tight, and the membranes and rods will not be exposed to the accompanying shock loads leading to membrane tear and rod breakage. The bags react upon the ship structure, which has air chambers connected to the bags with openings that can be closed off partially or completely, to change the response characteristics of the air bags and thereby of the seal.
U.S. Pat. No. 4,227,475 issued to Mattox discloses a waterborne air cushion vehicle having a flat rigid upper rectangular sheet like platform, a plurality of flat rigid longitudinal walls attached substantially at right angles thereto and depending therefrom substantially parallel with the major axis of the platform. The outermost two walls are disposed as sidewalls along respective edges of the platform. The vehicle is provided with flexible trough shaped skirts which are independently movable with respect to the walls. A source of pressurized air forces air into the skirts and also into air cushion chambers located beneath the platform. The flexible skirts provide for less shock and resistance from wave formations due to the compression of the skirts.
U.S. Pat. No. 4,350,107 issued to Mattox teaches a water borne air cushion vehicle having a flat rigid upper rectangular sheet-like platform, and a plurality of flat rigid longitudinal walls attached substantially at right angles thereto and depending therefrom substantially parallel with the major axis of the platform. Two of the walls are disposed as side walls along respective edges of the platform, and a plurality of longitudinally spaced laterally aligned arrays of flexible trough-shaped skirts are looped with a space therein and fastened along the longitudinal edge of the underside of the platform flush with, but movable with respect to adjacent pairs of the walls. The skirts are extendible to a lesser depth than that of the walls, and a source of pressurized air is admitted through apertures of fixed size at a relatively high pressure to the skirts. Also, low pressure air is admitted through variable sized openings remotely controlled and located beneath the platform in communication with at least four square or rectangular open bottom air cushion chambers disposed laterally in pairs. Each of the four square air cushion chambers is bounded by an adjacent pair of skirts and by an adjacent pair of walls, the depth of the walls and of the skirts being so related to the flow rate of the air that the vehicle is buoyant upon water. The walls protrude into the water sufficiently to prevent air spillage when the vehicle is urged longitudinally through the water by a propulsion system. The skirt air inlet openings are adapted to re-admit by reverse flow at least part of the compressed air in any one of the skirts independently in response to fugitive deflection of the skirts. The skirts are bag like structures attached along one side to the underside of the platform via a brace comprising a flexible sheet extending through the width of the skirt.
U.S. Pat. No. 4,766,829 issued to Schlichthorst discloses a catamaran-type cushion craft having two floats arranged space apart parallel to one another which are connected together at the top by a connecting structure which carries built in structures and which is sealed at the bottom by an air tight transverse deck. The connecting structure includes at least two transverse trussed girders arranged spaced apart behind one another, which at least partially contain transverse hollow cavities for passageways and line accommodating hollow cavities, with containers and longitudinal passage and supply elements being mounted at the front and/or rear sides of the double transverse trussed girders.
U.S. Pat. No. 5,146,863 issued to Ford discloses an air cushion displacement hull water vehicle that defrictionizes water flowing under the hull as the vehicle is propelled through the water. The hull includes a forward bow portion, an opposing aft end portion, a pair of sidewalls spaced from each other and extending there between the forward bow portion and the aft end portion, and a bottom wall extending between the forward bow portion and the aft end portion and between the pair of sidewalls. The bottom wall of the hull is recessed to define an air cushion region. An air supply device positioned within the interior of the hull communicates with the hull cushion region and is operable to supply pressurized air to the air cushion region to defrictionize water flow under the air cushion region.
U.S. Pat. No. 5,415,120 issued to Burg teaches a marine surface vehicle that includes pressurized supporting gas cushions in multiple hulls, normally catamaran-like sidehulls, where such pressurized supporting gas cushions support a majority of boat weight in operation. The preferred embodiment of the invention utilizes long fine pointed bow catamaran-like sidehulls that are in mechanical communication with a connecting hull structure. The long fine sidehulls offer performance advantages over a single large supporting gas cushion. Sidehull gas cushion outer sidewalls are preferably wider and deeper than inner sidewalls which insures maximum resistance coupled with maximum transverse stability in roll. Further, sidehull gas cushioned sidewalls optionally have angled to horizontal flatter surfaces forward and then transition to more rounded shapes aft which provides for a good pitch stability and minimum hydrodynamic resistance. The invention may include a hull on centerline that adds to stability in rough seas and gives a racy yacht-like appearance. Recesses in the sidehulls may include, at least in part, fixed and/or movable seals. Fixed seals may include inset vented steps to reduce wetted surface area. The recess gas pressurization system may include a controller to control pressures in individual recesses which allows at least some control of boat motions in rough seas. A further feature is the use of vertically oriented vented steps in the sides of the sidehulls to reduce wetted area drag when operating in rough seas. Another feature is the use of air flow turbulence generators on the underside, or wet deck, of the connecting hull structure to thereby increase static pressure lifting forces acting on the connecting hull structure.
PCT application No. WO 90/05660 filed by Brown discloses a ferry vessel having a main vehicle deck space and twin extended longitudinal casings having at their extremities large longitudinally closing watertight doors to divide the main vehicle space into three watertight compartments thereby limiting possible flooding of the vehicle deck in a side compartment due to damage such as collision, or to the center compartment upon breaching of bow or stern door. In the event of center compartment flooding, the intact outboard compartments provide substantial righting moment against listing. To further reduce the likelihood of flooding arising from side damage, the vehicle deck levels outboard of the casings may be raised to increase the vehicle's freeboard and the hull subdivision transverse bulkheads carried up such that their tops form a stepped V. Still further reduction of floodable areas is achieved by a system of transversely located floodgates.
Japanese patent publication 60-163788 discloses a car ferry with car carrying decks arranged in multilayers in a ship. The car carrying decks are formed into multiple band like partial decks serving as travel paths for car wheels. The band like partial decks are fitted on support cross beams arranged at a distance from each other. Since the car carrying decks are arranged only where car wheels are located, the hull weight can be largely reduced and the production cost of the hull can be decreased.
Russian patent publication No. SU-532-548 teaches a multideck car ferry having loading recesses that are positioned one above another on both sides of the ship. Ramps are mounted in loading recesses for car access to the main deck of the ship.
In metropolitan areas involving islands and related waterways, increasing population generates increasing needs to facilitate traffic flow across the waterways. These needs can be met by building bridges and/or by using and improving ferry systems. Obviously each approach to meeting the increasing needs has its relative advantages and disadvantages.
A need thus exists to improve the ratio of advantages to disadvantages for ferry systems, particularly the vessels used in the system, by improving the ratio of traffic flow rate capability of the vessels relative to their sizes as expressed in terms of their displacements.
A further need exists for a vessel capable of high speed, such as 40 to 50 knots, without creating unacceptable wake and with a low power to weight ratio and good fuel efficiency.
An additional need exists for a maximized ratio of usable to total deck space.
Another need exists for traffic flow onto, through and off the vessel virtually free of impediment caused by lane changing and/or use of ramps and ramp adjustment.
A final need exists for a vessel that is economical to construct and operate, and provides passenger comfort.

Displacement, submerged displacement, air cushion hydrofoil ferry boat


A multifunctional optical sheet for a liquid crystal display device includes a substrate diffusing incident light; a light-concentrating layer on the substrate and including a plurality of patterns that arranged to form alternating peaks and valleys; and reflection patterns between the substrate and the light-concentrating layer corresponding to the valleys of the light concentrating layer.

1. Field of the Invention
The invention relates to a liquid crystal display device, and more particularly, to a multi-functional optical sheet for a liquid crystal display device.
2. Discussion of the Related Art
With the rapid development of information technology, flat panel display (FPD) devices, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), electroluminescent display (ELD) devices and field emission display (FED) devices, have been developed and have replaced cathode ray tubes (CRTs).
Among these devices, liquid crystal display (LCD) devices widely used for monitors of notebook computers, monitors of personal computers and as displays for televisions because the LCD devices are excellent at displaying moving images and have a high contrast ratio.
LCD devices are not self-luminescent and require an additional light source. By disposing a backlight unit at the rear side of a liquid crystal (LC) panel to emit light into the LC panel, discernible images can be displayed. Backlight units may include cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs) or light-emitting diodes (LEDs) as a light source.
Backlight units are classified as edge type or direct type according to the position of the light source with respect to the display panel. In edge-type backlight units, one or a pair of lamps are disposed at one side or at each of two sides of a light guide panel of a backlight unit. In direct-type backlight units a plurality of lamps are disposed directly under a display panel.
FIG. 1 is a cross-sectional view illustrating a liquid crystal display (LCD) device including a direct-type backlight unit according to the related art. The related art LCD device includes a liquid crystal panel 10, a back light unit 50, a support main 60, a top cover 70 and a cover bottom 80. The liquid crystal panel 10 includes upper and lower substrates 13 and 15. A printed circuit board (not shown) is attached at a side of the liquid crystal panel 10. The support main 60 surrounds side surfaces of the liquid crystal panel 10 and the backlight unit 50. The top cover 70 covers edges of a front surface of the liquid crystal panel 10, and the cover bottom 80 covers a rear surface of the backlight unit 50. The top cover 70 and the cover bottom 80 are combined with the support main 60 to thereby constitute one-united body.
The backlight unit 50 includes a reflection sheet 40, a plurality of lamps 30, a diffuser plate 22, and a plurality of optical sheets 20. The plurality of lamps 30 are disposed over the reflection sheet 40, and the diffuser plate 22 and the plurality of optical sheets 20 are sequentially disposed over the plurality of lamps 30.
The plurality of optical sheets 20 includes a diffuser sheet and at least one light-concentrating sheet. The plurality of optical sheets 20 will be described in more detail with reference to FIG. 2.
FIG. 2 is a view schematically illustrating the diffuser plate and the plurality of optical sheets of FIG. 1. As shown in FIG. 2, the plurality of optical sheets 20 includes a diffuser sheet 24 and a light-concentrating sheet 26 sequentially disposed over the diffuser plate 22.
The diffuser plate 22 may be formed of transparent acrylic resin, polymethylmethacrylate (PMMA) or thermoplastic polyethylene terephthalate (PET) including irregular particles therein. The diffuser plate 22 may have various haze properties. The diffuser plate 22 directs light emitted from the plurality of lamps 30 of FIG. 1 towards the liquid crystal panel 10 of FIG. 1 and diffuses light such that light is incident on the liquid crystal panel 10 of FIG. from a relatively wide range of angles.
The diffuser sheet 24 positioned over the diffuser plate 22 is generally composed of a base film of PET and acrylic resin layers on both sides of a base film that includes a light diffuser such as beads. The diffuser sheet 24 diffuses light from the diffuser plate 22 so that there may be no patched portion due to partially centralized light, and the diffuser sheet 24 directs light towards the light-concentrating sheet 26.
The light-concentrating sheet 26 includes a base film of PET and prism patterns 28 regularly arranged on an upper surface of the base film. The prism patterns 28 generally reflect and concentrate light.
FIG. 3 is a view illustrating paths of light passing through the light-concentrating sheet of FIG. 2.
As shown in FIG. 3, light incident on the light-concentrating sheet 26 has an angle of about 5 degrees with respect to the normal to a lower surface of the light-concentrating sheet 26. Light incident on a light-concentrating region A is refracted by the prism patterns 28 and is concentrated toward the liquid crystal panel 10 of FIG. 1 to thereby cause an increase of brightness. Light incident on a total reflection region B is reflected downward at a surface of the prism patterns 28.
The reflected light is re-reflected by the reflection sheet 40 to be re-supplied to the light-concentrating sheet 26. Therefore, a loss of light is minimized.
However, in addition to the concentration and reflection of light in the light-concentrating sheet 26, there is a loss of light due to side lobes. This loss decreases light efficiency and adversely affects viewing angle properties of the display.
More particularly, in the figure, a region designated by C means a region where there occur side lobes, wherein the region C is referred to as a side lobe region. Light incident on the side lobe region C is refracted at the surface of the prism patterns 28 in an undesired direction and not toward the liquid crystal panel 10 of FIG. 1, and is wasted. In other words, there is light leakage in the side lobe regions C.
FIGS. 4 and 5 are graphs of illustrating distributions of brightness and distribution of light versus viewing angles for a backlight unit that includes the related art light-concentrating sheet of FIG. 3. As may be appreciated from FIGS. 4 and 5, there are bright areas at both sides with respect to a center region O, and there are side lobe regions C.
To solve the problems described above, a reflective polarizing sheet or a diffuser sheet for recycling light may be further disposed over the light-concentrating sheet to decreased or removed the side lobes to thereby improve a light efficiency and viewing angle properties. This solution increases the number of optical sheets used in a display and increases the manufacturing time for producing a liquid crystal display module. Accordingly, manufacturing process efficiencies are lowered and costs are increased.

Multifunctional optical sheet and liquid crystal display device including the same


An anti-notch filter in a servo control loop is phase locked to a nonrepeatable runout component of a servo control loop signal. The phase locked anti-notch filter may thereby more effectively track time varying characteristics of the nonrepeatable runout component so that they can be at least partially reduced in the servo control loop signal.

The present invention generally relates to controlling transducer movement and, more particularly, to controlling transducer movement responsive to a position error signal within a servo control loop.
A typical data storage disk drive includes a plurality of magnetic recording disks which are mounted to a rotatable hub of a spindle motor and rotated at a high speed. An array of read/write heads is disposed adjacent to surfaces of the disks to transfer data between the disks and a host device. The heads can be radially positioned over the disks by a rotary actuator and a closed loop servo system.
The servo system can operate in two primary modes: seeking and track following. During a seek, a selected head is moved from an initial track to a target track on the corresponding disk surface. Upon reaching the target track, the servo system enters the track following mode wherein the head is maintained over the center of the target track while data is written/read. During track following, prerecorded servo information sensed by the head is demodulated to generate a position error signal (PES), which provides an indication of the position error of the head away from the track center. The PES is then converted into an actuator control signal, which is fed back to an actuator to position the head.
In general, there are two forms of head positioning errors: repeatable and non-repeatable. Repeatable errors, which are generally caused by mechanical irregularities in the structure of the disc drive or errors introduced when writing the servo tracks, can be predicted and therefore theoretically can be cancelled out as they occur. In general, these repeatable runout errors (RRO) are removed by introducing a compensation signal into the servo loop that cancels the repeatable positioning error. Techniques for generating such compensation signals are generally referred to as feedforward cancellation.
Nonrepeatable runout (NRRO) disturbances can arise as a result of a variety of factors and the characteristics of the disturbance often vary depending on the source of the disturbance. Disc flutter disturbances have high energy concentrated at specific frequencies. Suspension windage-induced disturbances occur at higher frequencies and have wider bandwidths. Also, unlike RRO errors, NRRO errors do not occur with predictable magnitudes or frequencies. Moreover, the magnitude and frequency of NRRO error generally changes over time.

Phase locked anti- notch filter in a servo control loop