158 results about "Quasi periodic" patented technology

A method and system of interference lithography (also known as interferometric lithography or holographic lithography) which utilizes phase-locked, scanning beams (so-called scanning beam interference lithography, or SBIL). The invention utilizes a high-precision stage that moves a substrate under overlapped and interfering pairs of coherent beams. The overlapped beams interfere, generating fringes, which form a pattern “brush” for subsequent writing of periodic and quasi-periodic patterns on the substrate. The phase of the fringes in the overlapped region is phase-locked to the motion of the precision stage. The invention includes methods for forming, overlapping, and phase-locking interfering pairs of beams on a variety of substrates; methods for measuring and controlling the period, phase, and angular orientation of fringes generated by the overlapping beams; and methods for measuring and controlling the effects of stage mechanical and thermal drift and other disturbances during the writing process.

Several techniques are provided for use by wireless devices to avoid interference with signals that are of a periodic or quasi-periodic nature that may operate in the same frequency band and proximity. In some cases, the periodic signals are detected and their timing is determined so as to predict when a next interfering event will occur. Devices that are affected by the periodic signal (such as an affected device with information to be transmitted or devices that have information to be transmitted to the affected device) are controlled to prevent transmissions during the interfering intervals. In addition, a process is provided to dynamically fragment a transmit frame of information to transmit part of the information before the interfering interval and the remainder of the information after the interfering interval, rather than waiting to transmit the entire frame until after the interfering interval. Moreover, techniques are provided to correct for clock drift between the periodic signal and a device affected by the periodic signal, as well as for clock drift between a device affected by the periodic signal and other devices that communicate with that device. These techniques prevent interference with periodic signals and in so doing, improve the quality of service of the communication link for both the interfering devices and the other devices.

The invention relates to a physiological signal quality evaluation method and system based on constrained estimation. The method comprises the following steps: receiving to-be-evaluated signal sections of a quasi-periodic physiological signal, performing pretreatment, waveform analysis identification and signal period segmentation to the signal sections, carrying out feature point detection to each cycle of signal section, and extracting preset physiological feature parameters of the physiological signal; for each signal section, combining the extracted physiological feature parameters to form feature vectors, performing constraint-based modeling according to transcendental knowledge of the physiological signal, and further establishing an analyzable evaluation system with constraint timing; and using a constraint evaluation model to trace sequential change of physiological parameters, combing a preset rule base and sequential change information, rating the signal quality of the quasi-periodic physiological signal, evaluating the validity of signal data of the signal sections of the quasi-periodic physiological signal, updating a time sequence evaluation system, and rating according to iteration of the periodic signal sections until the signal quality rating of all the signal sections of the quasi-periodic physiological signal is finished.

The present invention provides a system and method for representing quasi-periodic (“qp”) waveforms comprising, representing a plurality of limited decompositions of the qp waveform, wherein each decomposition includes a first and second amplitude value and at least one time value. In some embodiments, each of the decompositions is phase adjusted such that the arithmetic sum of the plurality of limited decompositions reconstructs the qp waveform. These decompositions are stored into a data structure having a plurality of attributes. Optionally, these attributes are used to reconstruct the qp waveform, or patterns or features of the qp wave can be determined by using various pattern-recognition techniques. Some embodiments provide a system that uses software, embedded hardware or firmware to carry out the above-described method. Some embodiments use a computer-readable medium to store the data structure and/or instructions to execute the method.

An apparatus for emitting light with a controlled directionality and optical divergence from at least one opening includes a light impervious surface structure having the at least one opening, a periodic or quasi-periodic surface topography including one or several surface feature(s) and associated with the at least one opening on the surface structure, whereby light emerging from the opening(s) interacts with surface waves on the surface structure (20) thereby providing controlled directionality and optical divergence of the emitted light.

The present invention provides a system and method for representing quasi-periodic (“qp”) waveforms comprising, representing a plurality of limited decompositions of the qp waveform, wherein each decomposition includes a first and second amplitude value and at least one time value. In some embodiments, each of the decompositions is phase adjusted such that the arithmetic sum of the plurality of limited decompositions reconstructs the qp waveform. These decompositions are stored into a data structure having a plurality of attributes. Optionally, these attributes are used to reconstruct the qp waveform, or patterns or features of the qp wave can be determined by using various pattern-recognition techniques. Some embodiments provide a system that uses software, embedded hardware or firmware to carry out the above-described method. Some embodiments use a computer-readable medium to store the data structure and/or instructions to execute the method.

A method of detecting impairment of a driver of a vehicle. The method includes sensing, using a sensor, a position of the driver's head at a plurality of time points; determining, using a microprocessor, changes in the position of the driver's head between the plurality of time points; evaluating, using a microprocessor, whether the changes in the position of the driver's head between the plurality of time points exhibit at least one of a periodic and a quasi-periodic pattern; determining whether the driver is impaired based on the pattern of the changes in the position of the driver' s head; and if the driver is impaired, alerting the driver using an alarm.

Accommodative and vergence systems training method and multifocal ophthalmic lenses of Horizontal periodic or quasi-periodic Optical Power Stepless Alternating (HOPSA-lenses) therefor are proposed. Reading the text with HOPSA-lenses worn, while the head is stationary, provides a continuous alternating of accommodation and vergence strain/relaxation and, therefore, provides dynamic training of both systems. The method is applicable for human visual system therapy, eye diseases treatment/prevention and ophthalmology researches. The method enables combining the effective visual trainings with documents reading/processing, visual target examining, watching TV/video, playing computer games, etc., as well as combining the training with conventional vision correction. Several embodiments of HOPSA-lenses are disclosed, such as multi- and mono-cyclic, multi-layer, splitting the basic correction and training functions between lens' sides or layers, having left and right lenses' surfaces individually configured to provide the congruence of optical power for fixation, and/or the convergence invariability for fixation during the training.

Metrology methods and targets are provided, that expand metrological procedures beyond current technologies into multi-layered targets, quasi-periodic targets and device-like targets, without having to introduce offsets along the critical direction of the device design. Several models are disclosed for deriving metrology data such as overlays from multi-layered target and corresponding configurations of targets are provided to enable such measurements. Quasi-periodic targets which are based on device patterns are shown to improve the similarity between target and device designs, and the filling of the surroundings of targets and target elements with patterns which are based on device patterns improve process compatibility. Offsets are introduced only in non-critical direction and/or sensitivity is calibrated to enable, together with the solutions for multi-layer measurements and quasi-periodic target measurements, direct device optical metrology measurements.

Cardiac computed tomography (CT) has been a hot topic for years because of the clinical importance of cardiac diseases and the rapid evolution of CT systems. In this application, we disclose a novel strategy for controlled cardiac CT (CCCT) that may effectively reduce image artifacts due to cardiac and respiratory motions and reduce the scan time. Our approach is radically different from existing ones and is based on controlling the x-ray source rotation velocity and powering status in reference to the cardiac motion. By such a control-based intervention the data acquisition process can be optimized for cardiac CT in the cases of periodic and quasi-periodic cardiac motions. Specifically, we present the corresponding coordination/control schemes for either exact or approximate matches between the ideal and actual source positions.

The invention discloses a quasi-periodic handoff triggering mechanism based on handoff invitation sending. The quasi-periodic handoff triggering mechanism based on handoff invitation sending comprises, according to the mobile line diagram and the moving speed of a mobile terminal as well as the localization information of the base station of a serving cell and the base station of a neighboring cell to structure a cell cluster and to determine the reference time, the basic period and the quasi-period for transmitting handoff invitation; transmitting the handoff invitation to the mobile terminal periodically through every substation in the cell cluster and accordingly triggering handoff. The quasi-periodic handoff triggering mechanism based on handoff invitation sending overcomes the shortcomings of traditional handoff triggering mechanisms based on signal strength receiving and enables handoff triggering to be timely, accurate and reliable, and meanwhile, shortens the executing time for handoff, improves the handoff speed and efficiency and avoids ping-pong handoff, thereby having a broad application prospect in wireless communication environments with relatively fixed mobile lines and relatively high moving speed such as high-speed railways, highways, urban BRT (bus rapid transit) and the like.

A device for sorting and concentrating electromagnetic energy impinging a surface of the device, the surface including at least one plasmonics-based surface structure or similar structure of periodic or quasi-periodic surface topography. The device is characterized in that the surface (V) is provided with at least two such surface structures (2), acting as individual concentrator structures, which are at least partially spatially overlapped or superposed.

Disclosed is a method for preparing quasi-periodic micro-lens arrays through femtosecond laser wet etching. The method comprises that the velocity of a target material moved by an accurate processing platform is controlled according to the individual average size of quasi-periodic micro lenses needed to be processed, femtosecond lasers act for one pulse on the target material surface at a fixed interval, and a light damage area is produced on the target material with the acting focus of each femtosecond laser pulse serving as a center; chemical corrosion is performed on the target material processed by the femtosecond lasers through a hydrofluoric acid solution with a volume concentration in a range of 1% to 10%, and ultrasonic water-bath heating is assisted; and the corroded target material is cleaned thoroughly in deionized water to obtain a template finished product of mass quasi-periodic micro-lens arrays. The method has the advantages of being high in efficiency, low in cost, controllable in micro-lens individual shape size and the like, and negative effects of air breakdown effects of laser focusing, periodic light field coupling stacking effects and the like generated in a dodging process can be prevented effectively.

A bulk, quasi-periodic phase-matched difference-frequency (DFG) process in field-poled LiNbO.sub.3 bulk crystal permits continuous tunability of the output radiation in the 3.0-4.1 .mu.m wavelength range through grating rotation. DFG in QPM-LiNbO.sub.3 crystal, carried out using a Nd:YAG laser and a high power semiconductor laser at the quasi-phased matching (QPM) degeneracy point, results in an ultra wide 0.5 .mu.m acceptance bandwidth, permitting crystal rotation-free wavelength tuning of 4.0-4.5 .mu.m, with 0.2 mW output power at 4.5 .mu.m.

A thin-film optoelectronic module device (100) and design method comprising at least three monolithically-interconnected cells (104, 106, 108) where at least one monolithically-interconnecting line (250) depicts a spatial periodic or quasi-periodic wave and wherein the optoelectronic surface of said thin-film optoelectronic module device (100) presents at least one set of at least three zones (210, 220, 230) having curves of substantially parallel monolithic interconnect lines. Border zones (210, 230) have a lower front-contact sheet resistivity than th at of internal zone (220). Said curves of substantially parallel interconnecting lines may comprise peaks of triangular or rounded shape, additional spatial periods that are smaller than a baseline period, and mappings from one curve to the adjacent curve such as in the case of non-rectangular module devices (100). The device (100) and design method are advantageous to reduce costs and materials to manufacture thin-film optoelectronic module devices (100) while increasing production yield, reliability, aesthetic appearance, and range of applications.

A lithographic method related to Talbot imaging for printing a desired pattern of features that is periodic or quasi-periodic in at least one direction onto a substrate surface, which method includes providing a mask bearing a pattern of mask features, arranging the substrate parallel and in proximity to the mask, providing an illumination source having a central wavelength and a spectral bandwidth, forming from said source an illumination beam with an angular distribution of intensity, arranging the distance of the substrate from the mask and exposing the mask pattern to said beam so that each angular component of illumination exposes the substrate to substantially the entire range of lateral intensity distributions that occur between successive Talbot image planes for the illumination wavelengths, wherein the angular distribution of the beam is designed in conjunction with the pattern of features in the mask and the distance of the substrate from the mask.

A composite material that may be used for a thin membrane is disclosed. This composite material includes first material that has a quasi-periodic system of vertical trenches (nanotrenches) with wavelength period that may be in the range between 20 and 500 nm. These nanotrenches are formed as openings between bordering elongated elements. The nanotrenches are at least partially filled with a second material that has physical-chemical characteristics substantially different from the first material.

A light-emitting device includes a substrate, a semiconductor stacked structure positioned on the substrate, a transparent electrode positioned on a first region of the semiconductor stacked structure, and at least one photonic crystal positioned in a second region of the semiconductor stacked structure. Preferably, the first region surrounds the second region, the area of the first region is larger than that of the second region, and the width of the second region is smaller than 40 micrometers. The structure of photonic crystals can be holes, pillars, continuous protrusions or depressions, discontinuous protrusions or depressions or the combination thereof, and the lattice of photonic crystals can be square, hexagonal, rectangular, periodic, multi-periodic, quasi-periodic or non-periodic.

A system includes an electronic stethoscope producing a quasi-periodic signal, a processor, and a memory device with stored instructions that, when executed by the processor, cause the system to receive a representation of the quasi-periodic signal, to remove a DC component from the received representation of the quasi-periodic signal to produce a purely time-varying signal, and to filter, the time-varying signal to produce a pre-processed signal. A portion of the pre-processed signal is auto-correlated with itself, and a corresponding auto-correlation output is stored. A biphasic tapering function is applied to the auto-correlation output and produces a first maximum, the function including a time constant parameter that is a function of the quasi-periodic signal. A representation is stored, based on the first maximum, as an indication of a rate or frequency of the quasi-periodic signal.

A spatially modulated waveguide Bragg grating mirror is suspended over a substrate by plurality of fingers extending laterally away from the waveguide centerline. The positions of the fingers are coordinated with the positions of crests and valleys of amplitude or phase modulation of the Bragg grating, to avoid disturbing the Bragg grating when it is tuned by heating. When the Bragg grating is heated, the heat flows through the fingers creating a quasi-periodic refractive index variation along the Bragg grating due to quasi-periodic temperature variation created by the heat flow from the grating through the supporting fingers. Due to coordination of the positions of supporting fingers with positions of the crests and valleys of modulation, the optical phase coherence is maintained along the Bragg grating, so that the spectral lineshape or filtering property of the Bragg grating is substantially preserved.