828results about How to "No error" patented technology

The invention relates to a comprehensive measuring and controlling device of a high voltage pole tower, mainly comprising a power supply unit, an intelligent bird driving unit, a flashover and lightning stroke location detection unit, a pole tower inclination detection unit, a pole tower meteorological environment detection unit, a pole tower intrusion alarm unit, an transmission line icing parameter detection unit, a central controller, a wireless transceiving device and a thermostat, wherein the power supply unit comprises two parts which are a solar battery and a wind turbine, the wind turbine also fulfills the functions of wind speed and wind direction detection and is an important component part of the pole tower meteorological environment detection unit, the power supply unit stores collected electric quantity into a storage battery through a collection circuit and supplies the power to the device, and the wireless transceiving device sends information collected in situ to a distant monitor center through a GPRS (General Packet Radio Service) or a wireless local network. The invention can fulfill the functions of intelligent bird driving, flashover and lightning stroke location, pole tower inclination detection, meteorological environment detection, intrusion alarm, icing parameter detection and the like and has strong environment adaptability because the wind power and the solar power generation accord with the environment self-powered requirement, thereby enhancing the maintenance free performance of a system. The device is an important component part of an intelligent power grid, accords with the requirement of intelligent power grid establishment of a national power grid and has higher practical value and wide application prospect.

The invention relates to delta-pack-based software upgrading method, and in particular provides a software upgrading delta pack acquiring method and device. Files of the same name, which have a difference, in an installing pack and an upgrading pack are subjected to differentiation in the form of source data, so that a delta pack with a smaller volume is obtained. Correspondingly, the invention further provides a software updating and upgrading method and a software updating and upgrading device. The delta pack is used for reducing the upgrading pack according to the inner structure of a zip file of the upgrading pack. According to the scheme, a user can quickly realize updating and upgrading of software in a more flow-saving manner by downloading the delta pack with the smaller volume.

The invention discloses an RFID management system for site construction worker safety. The RFID management system comprises a pair of safety shoes, a safety helmet, a gate, a camera, a wireless router, an optical transmitter and receiver, an interchanger, a hand-held terminal, an intelligent terminal, a server, a PC and a television wall; the safety shoes, safety helmet, gate and hand-held terminal are connected in a wireless mode through an RFID mode; the hand-held terminal, intelligent terminal, gate and server are connected in a wireless mode; the interchanger, television wall, PC and server have communication connection; the camera is electrically connected with the wireless router and optical transmitter and receiver; the wireless router, optical transmitter and receiver and interchanger are electrically connected; the hand-held terminal comprises a violation information acquiring module, a violation processing module and a data updating module; the violation processing module is connected with the data updating module; the server comprises a management inquiry platform and a central service platform; the management inquiry platform is connected with the central service platform; the management inquiry platform comprises a verification module, a personnel registration module, an attendance inquiry module, a violation inquiry module and a user management module.

The invention discloses a method for calibrating verticality of a magnetic shaft of a three-shaft magnetic sensor. A three-dimensional magnetic field generator and a nonmagnetic rotary table are adopted, the three-dimensional magnetic field generator and the nonmagnetic rotary table are arranged at first; the magnetic sensor which needs to be calibrated is fixed on the rotary table; a large magnetic field ranging from top to bottom is generated by the magnetic field generator, so that a numeric value measured by the sensor is not zero; the zero position of the rotary table is marked, the angle values of three shafts of the rotary table are recorded, and three shafts of the rotary table are rotated, so that the outputs of a shaft m and a shaft n of the sensor are zero and the angle values of the three shafts of the rotary table are recorded; the three shafts of the rotary table are rotated again, so that the outputs of a shaft m and a shaft n of the sensor are zero and the angle values of the three shafts of the rotary table are recorded; transformation relation between each shaft m, n and p of a coordinate O and each shaft x3y3z3 of the coordinate O3 can be obtained by calculating multiple recorded angle values so as to obtain a calibration result. The method is simple and feasible, high in accuracy and small in errors.

The invention discloses a speed reducer testing equipment which is used for testing the return difference and the elastic constant of a speed reducer to be tested. The speed reducer testing equipment comprises a support platform, and a servo motor, an input rotating wheel, an output rotating wheel, load equipment and an angle sensor which are arranged on the support platform, wherein an output shaft of the servo motor is connected with one of a first side shaft and a second side shaft, which are opposite, of the input rotating wheel so as to drive the input rotating wheel to rotate around a first rotating shaft defined by the first side shaft or the second side shaft; the speed reducer to be tested and the angle sensor are respectively connected with a third side shaft and a fourth side shaft, which are opposite, of the output rotating wheel; the output rotating wheel is meshed with the input rotating wheel to further synchronously rotate around a second rotating shaft which is defined by the third side shaft or the fourth side shaft and parallel to the first rotating shaft; the angle sensor is used for obtaining a torque angle of the speed reducer to be tested. Due to the adoption of the mode, according to the speed reducer testing equipment disclosed by the invention, the angle measurement precision of the speed reducer to be tested is improved.

The invention relates to a test method, in particular to a pull-off force test method, which mainly comprises the following steps: processing a specimen; processing a plunger, in which the plunger is installed at the top of a pipe piece; processing a pull-off force test fixture; carrying out a pull-off force test; and assessing the welding process according to the tensile strength value. The pull-off force test method has the advantages of simpleness in operation, low cost, convenience in use, safety and reliability, real and reliable test data, and no errors, and is very suitable for the assessment of the welding process.

A corrective / ophthalmic lens comprising an impact lip extending from an anterior lens edge and a radial groove adjacent and parallel to the lens lip posterior surface, an eyewear system containing a corrective / ophthalmic lens and a method of making a lens is provided. The lens impact lip size is variable, determined by frame function and the degree of impact protection that is necessary. A posterior surface of the lens impact lip is beveled with a curvature that preferably substantially matches and coincides with the lens anterior curves, producing a lip with no corrective, low residual power effect or negative image effects. Due to the absence of image change and effects through the lens impact lip, in one aspect the present invention eliminates restrictions to the size of the impact lip.

An air float multi-dimension force sensor and a multi-dimension force measuring method are characterized in that the invention is provided with a rectangle hexahedron floating plate; each surface corresponding to the floating plate is respectively provided with a nozzle; each nozzle and the surface corresponding to the floating plate form a nozzle baffle type pressure sensor; the rectangle hexahedron floating plate is led to be fully suspended and floated by the pressure air sprayed out from each nozzle; a pressure signal of a bearing cavity of each nozzle is a detecting output signal. The method for measuring multi-dimension force has no coupling among dimensions, needs no complex decoupling procedure and can effectively improve measuring precision.

The invention relates to a bi-pentabasic cross-array passive acoustic location integrating method and belongs to the technical field of acoustic signal processing and measuring. The bi-pentabasic cross-array passive acoustic location integrating method solves the problems that orientation and distance accuracy of an existing quaternary cross-array location method are related to directions of targets, but which areas the targets are located are incapable of being judged, error exists in ranging and side direction of an existing pentabasic cross array, particularly when the targets and a planar array form small included angles, ranging and side direction error is large, some distances are ignored in formula derivation and resultantly some errors are caused, estimation accuracy is decreased and actual engineering application is damaged. The bi-pentabasic cross-array passive acoustic location integrating method is structured by seven microphones, accurate coordinate calculation formulas of sound source points are derived by two pentabasic cross arrays respectively, and a calculation formula of the sound source coordinate values is structured by introducing a weighted arithmetic average method by means of the calculation formulas of the pentabasic cross arrays. The bi-pentabasic cross-array passive acoustic location integrating method is applicable to the field of passive acoustic source location on basis of delay estimation.

The invention discloses an online measurement device and a measurement method thereof for a pipeline flux instrument, comprising a detection terminal and a background management unit; the detection terminal comprises a flowmeter, a camera, a DSP module and a communication unit connected with the DSP module; the background management unit comprises a central control unit and a communication module connected with the central control unit; the detection terminal and the background unit carry out data communication by a GPRS wireless network and / or an Internet; the output terminals of the camera and the flowmeter are respectively connected with the image signal input terminal and the flux value signal input terminal of the DSP module; the camera of the detection terminal right faces to the dial plate of the instrument to be measured; the flowmeter is arranged on the pipeline; and the background management unit respectively obtains the accumulated flux in the pipeline within unit time by the camera and the flowmeter in the detection terminal so as to calculate the measurement error of the instrument to be measured.

The present invention relates to an asphalt pavement automatic repair equipment for asphalt concrete roads, comprising a cutting device, a material conveying and rolling moving device, a crushing device and a grabbing device, and the cutting device is installed on the upper end of the conveying and rolling moving device On the front side of the conveyor, a crushing device is installed on the right side of the upper end of the material conveying rolling mobile device, and a grabbing device is installed on the upper left side of the material conveying rolling mobile device. The present invention can solve the problem that in the process of repairing the ground on the existing asphalt road, the waste materials are dug away manually and then grouted and rolled. There are deviations in the manual marking and cutting of the staff, and there are safety hazards at the same time. The construction personnel shatter the ground with the help of tools At the same time, the dead corner areas on the four sides cannot be completely shattered, and the surrounding small areas cannot be fully excavated. People use existing tools to grout the construction area and then use rolling props to roll the ground. The work is labor intensive and efficient. Low-level problems can realize the automatic repair function of asphalt pavement.

The invention discloses a pedestrian clothing color identification method based on digital image processing. The method comprises the steps that (1) a pedestrian detection method which combines an HOG feature description operator and a SVM classifier is used to acquire a pedestrian image; (2) a Sobel operator is used to detect the edge contour shape of a pedestrian to acquire an image to be searched; (3) a pedestrian contour shape template is produced and matches a corresponding region in the image to be searched to acquire upper and lower body images of the pedestrian; (4) a seed filling method is used to carry out communication region labeling on clothing colors of upper and lower body regions of the pedestrian; (5) color feature extraction is carried out on a color communication region; and (6) the SVM classifier is used to carry out color classification discrimination to acquire the clothing color of the pedestrian, and a final result is output. According to the invention, the identification accuracy of the clothing color of the pedestrian is improved; standardized dress in a dangerous region is ensured; and safety risks are eliminated.

The invention discloses a visual odometer realization method based on fusion of RGB and depth information. According to the existing visual odometer realization method, only environmental RGB information can be obtained based on a monocular or binocular camera and three-dimensional information of the environment can not be obtained directly, so that the application environment of the method is limited and the precision is high. Besides, an RGB-image-matching-based positioning method has characteristics of mature technology and fast processing speed; and a Depth-image-matching positioning method has the characteristic of high environment changing robustness. According to the invention, with combination of the advantages of the RGB-image-matching-based positioning method and the Depth-image-matching positioning method, an RGB-D sensor is used for obtaining RGB and Depth information of a scene simultaneously and a visual odometer realization method based on fusion of RGB and depth information is provided. Information of 2D and 3D modes is utilized reasonably; the dependence on the illumination condition by the visual system is broken; precision, robustness, and practicability of the speedometer system can be improved substantially; and the application time and space for the mobile robot can be expanded.

The invention provides a time domain analysis method for a transient response of lossy nonuinform multi-conductor transmission lines and aims to solve the problem that the coupling among the lossy nonuniform multi-conductor transmission lines interferes with the computation in the field of integrity of electronic circuit signals. The method comprises the following steps of: performing differential dispersion on space differential operators in an electric wave equation; and integrating time differential operators in the electrical wave equation by a trapezoidal integration method to ensure that the oscillation, which is caused by a central difference method, of a computed result can be eliminated effectively, voltage and current transient response waveforms of any point on the transmissionlines can be acquired; and the transient analysis of the transmission lines in a longer time period is effective, the waveforms can be analyzed in a longer duration without large errors, and the coupled transmission lines are not needed to be decoupled when a model of the transmission lines is built. By the method, the computational load is reduced, and the simulation efficiency is improved. The method can be used for analyzing the transient response of the lossy nonuinform multi-conductor transmission lines.

The invention discloses a micro capacitance measurement method and a special device. The device is provided with a sine wave voltage driving source, a current-limiting resistor, a preposed operational amplifier, a feedback resistor, a voltage follower, an amplifying unit, a reference signal generator, a multiplying unit, a low-pass filter, a selective switch and a detection processing unit. The precision and the resolution of the method are high to the micro capacitance measurement.

The invention discloses a ship behavior track recognition method. The method comprises the following steps of: obtaining a track of a ship according to a track parameter; carrying out region divisionon the current sea area in which the ship travels according to the geographic condition of the current sea area; dividing a sea area track section by using a corner method according to the divided seaarea, so as to obtain a plurality of ship sub-track fragment sets; carrying out error back propagation multilayer feed-forward network set clustering on the plurality of ship sub-track fragment sets,so as to obtain a typical ship behavior track mode; calculating a Hausdoff distance between a track of a to-be-recognized ship and the typical ship behavior track mode; setting a Hausdoff distance threshold value; and judging a behavior track mode of the to-be-recognized ship according to a comparison result between the Hausdoff distance and the Hausdoff distance threshold value, and if the Hausdoff distance is smaller than or equal to the Hausdoff distance threshold value, judging the behavior track mode of the ship as the typical ship behavior track mode. The method is capable of correctlyand rapidly judging behavior modes of ship tracks, avoiding the waste of offshore management resources and ensuring the personal and property safety of seamen.

The invention discloses a three-dimensional positioning and guiding device for penetrating a vertebral pedicle through skin. The three-dimensional positioning and guiding device for penetrating the vertebral pedicle through the skin comprises a base, dip angle measuring devices and a measuring device supporting rod, wherein guiding grooves are arranged in length wise frame edges of the base, two dip angle measuring devices are matched on the measuring device supporting rod in a sliding mode, and an arc-shaped guiding groove is arranged in each dip angle measuring device. A bar-shaped hole is arranged in the measuring device supporting rod, a puncture needle guiding tube is in hinge joint with the dip angle measuring devices, and the puncture needle guiding tube penetrates through the bar-shaped hole. A guiding pin is arranged on the puncture needle guiding tube and is matched with the arc-shaped guiding grooves, marking needle fixing holes are arranged in the middle portion of the measuring device supporting rod, and two ends of the measuring device supporting rod are cylindrical segments. The measuring device supporting rod is matched with the guiding grooves in a sliding mode through sliding blocks, the cylindrical segments of the measuring device supporting rod extend out of the sliding blocks and are connected with a positioning rod, and the positioning rod is in the same plane with the measuring device supporting rod and the puncture needle guiding tube. The three-dimensional positioning and guiding device for penetrating the vertebral pedicle through the skin is capable of three-dimensional positioning and guiding and shortening the operation time, high in efficiency, accurate in guiding and capable of improving the achievement ratio of operation.

The invention discloses an electroplastic incremental forming device for a plate and a working method thereof, and belongs to the field of metal processing. The device comprises a machine tool and a pulse power supply, wherein a plate clamping device is fixed on a workbench of the machine tool; a clamping block, an electric brush holder and a retainer are arranged on a main shaft of the machine tool; the clamping block is connected with a tool head used for processing the plate; the electric brush holder is L-shaped, one end of the electric brush holder is fixed on the main shaft, and the other end of the electric brush holder is connected with an electric brush used for being abutted against the clamping block; the retainer is U-shaped, one end of the retainer is fixed on the main shaft, and the other end of the retainer stretches to a place below the plate and is connected with a lower press head used for being abutted against the lower surface of the plate; the tool head faces the lower press head; and the two poles of the pulse power supply are connected with the electric brush and the lower press head respectively. The electroplastic incremental forming device for the plate disclosed by the invention is simple in structure, easy to control, and low in processing cost; the forming accuracy of the plate is high; and the forming limit and the forming quality of the plate are increased and improved.

Provided is a data block backup method which comprises that: a Hash table storing names of file data blocks and Hash values of all the data blocks is uploaded to a Hash database, and the data blocks are uploaded to a data login area of a server according to the segmentation sequence of the data blocks; repetition of uploading of all the data blocks is judged according to the sequence in which the data blocks enter into the data login area, when the judgment result is that the data blocks are in a storage area of the server, the data blocks are confirmed to be duplicated data blocks, and the data blocks in the data login area are deleted; when the duplicated data blocks have no backup, the duplicated data blocks are stored in a backup area of the server; and storage pointers of the data blocks and the pointers of backup blocks are additionally stored in the Hash database. The invention also provides a data block backup system. The situation that files cannot be used due to damage, tampering or loss of the data blocks which are cited for multiple times can be avoided by utilizing the method.

The invention discloses a method for synchronously inhibiting radar clutter and multiple interferences based on power distinction, and is suitable for a signal processing system of sky-wave over-the-horizon radar. The method realizes the separation of strong clutter, interferences and target signal using the power difference among the clutter, interferences and target signal, and can effectively inhibit clutter and multiple interferences including transient interference and shared-frequency asynchronous interference. The specific steps are showed in the figure 1. Compared with the prior method, the method does not need to detect and analyze the clutter and multiple interferences complicatedly, has obvious effect on the randomly varied interferences of all parameters and clutter, and has strong applicability. The invention uses the separated strong clutter as a standard signal to correct phase pollution, can realize phase correction and inhibit the clutter and interferences synchronously, and simplify the signal processing process of the sky-wave over-the-horizon radar. The invention is not limited to the sky-wave over-the-horizon radar system, can be widely applied to multiple large-scale phased array radars, and has wide application value.

The invention discloses a method used for obtaining the three-dimensional attitude of a carrier and based on horizon and polarized light. The method comprises: firstly, detecting the horizon by usinga foresight camera of a carrier, and reckoning the roll angle and the pitch angle of the carrier according to the position of the horizon in an image and the parameters of the camera; secondly, obtaining a sky polarization information image according to a polarization camera, extracting a polarization neutral point from the polarization degree image by using an ellipse fitting method, and establishing a carrier three dimensional attitude equation according to the transformational relation of the polarization neutral point between a camera coordinate system and a geographic coordinate system; and finally bringing the roll angle and the pitch angle obtained from horizon navigation to the three dimensional attitude equation to solve the course angle of the carrier, thereby obtaining the threedimensional attitude of the carrier. The method is full-autonomous and passive.

The invention relates to optical measuring equipment. The optical measuring equipment comprises an equipment cabinet, a positioning device, a measuring system and a project control system, wherein a working table is arranged at the upper end of the equipment cabinet, and the working table is provided with a gantry structure frame; the positioning device is arranged on the working table, and the positioning device is used for bearing and fixing a workpiece and can drive the workpiece to move on the working table; the measuring system is arranged on the gantry structure frame and located above the positioning device, and is used for measuring the data of the inner length, the inner width, the outer length and the outer width of the workpiece as well as the width, the profile tolerance, the flatness, the parallelism, the height difference and the like of a specific face; the project control system is arranged in the equipment cabinet, and is used for controlling the positioning device and the measuring system, and calculating and analyzing the data fed back by the measuring system. The optical measuring equipment achieves multi-project automatic detection, and has the advantages of being high in precision, few in man-made interference factors, low in cost and high in efficiency.

The invention discloses a low-power Bluetooth intelligent asset management apparatus with an identity recognition function. The apparatus comprises electronic tags, an APP loading body and a server, wherein the electronic tags actively send out signals used for the APP loading body to receive, and the single APP loading body receives the signals sent by the electronic tags at the same time; an APP loaded on the APP loading body performs asset check through identity authentication, system updating, data downloading, tag configuration, tag locating and asset management; and during asset management, tag broadcasts are scanned through a Bluetooth module of the APP loading body, then identification and classification processing is performed through a fast addressing algorithm, and the asset management and statistics are finished. The deficiencies of low asset management efficiency, poor timeliness and high error rate caused by existing electronic tag collision and environment interference are overcome; and the apparatus has the characteristics of real-time asset management, high efficiency, no errors, localizability, rechargeability, reusability and the like.

The invention belongs to the electronic invoice application technology field, and relates to an electronic invoice issuing method. Valid effective invoice issuing of an electronic invoice is realized by setting a plurality of servers of a cloud platform and invoking tax control devices of taxpayers. The electronic invoice issuing method mainly comprises an invoice issuing information uploading step, an invoice issuing information preprocessing step, an invoice issuing processing step, and an invoice pushing step. The set cloud platform is used to guarantee the stability of the issuing of the electronic invoice safely and reliably, is used to improve the issuing efficiency, and is used to guarantee the safety of the storage of the electronic invoice, and is also used to realize automatic price and tax separation, discount calculation, and invoice reissuing processing automatically and correctly by the set preprocessing servers, and therefore issuing efficiency is improved. The above mentioned three invoice issuing ways are used to satisfy the requirements of the various taxpayers on the issuing of the electronic invoices. The set servers are stable and safe. The issuing method is simple to operate, and is easy to understand, and the electronic invoice issuing is valid and errorless, and application environment is friendly.

The invention relates to a horizontal well segmented temporary blockage fracturing method and belongs to the technical field of hydraulic fracturing of oil and gas field development. The method comprises the steps of: carrying out temporary blockage on a perforation of a horizontal well; forming a new crack around the temporary blocked perforation; and repeating the process above. The horizontal well segmented temporary blockage fracturing method achieves a segmented fracturing effect on a well section of a horizontal well and provides a more effective, rapider and more convenient mode for development of the horizontal well. Meanwhile, after a temporary blockage agent is degraded, a crack end port also can be supported so as to improve a fracturing success rate; the temporary blockage agent cannot be left in a shaft, meanwhile, has a very high degradation rate in fracturing fluid, and cannot generate pollution to the stratum, so that the transformation effect is greatly promoted.

To enable to display a scale indicative of a reference length on a screen of a display at an accurate length even when exchanging the lens in an image pickup apparatus to any lens.In a case of mounting an exchange lens (4F, 4Z) to an image pickup apparatus main body (3) and displaying an image of an object picked up by an image sensor (2) and a scale (5) indicative of a reference length in juxtaposition on a screen of a display (6), a previously measured optical magnification or an actual magnification is outputted from optical magnification outputting means (8) provided to the exchange lens (4F, 4Z) is outputted, an actual magnification on the screen of the display (6) is calculated based on the optical magnification, the size for the image sensor and the screen size, and the size of the scale on the screen is set based on the actual magnification and the reference length of the scale by a scale setting means (17).

A scanning probe (1, 10) according to the present invention includes a measurement stylus (stylus) (6) movably supported via elastic members (5D, 5E, 5F) on a probe body (4), fine feeders (3, 7) for moving the probe body (4) and the measurement stylus (6) against a workpiece within a fine range, a contacting force detector (5G) for detecting a contacting force between the measurement stylus (6) and a surface of the workpiece, and a contacting force adjuster (8) for adjusting the contacting force by removing the inertial force acting to the measurement stylus (6) because of acceleration from the contacting force. Because of this feature, a measuring force can be adjusted by providing feedback controls to the fine feeders (3, 7), so that the tracking capability is ensured to provide a high response rate and high precision in measurement. Further by eliminating influence of the inertial force of the measurement stylus (6), a measurement error is corrected to obtain a correct measuring force, and high precision measurement can be executed.

The two-dimensional image area positioning method based on the grating projection can determine the source and characteristic of image noise for noise inhibition. The method includes the following steps: taking the datum picture with CCD camera before projecting one coarse set or fine set of grating to the object before taking one image and obtaining coarse positioning image through threshold parting, image filtering, etc; filtering the image with fine grating image to obtain the fine grating grey image; non-interlaced traversing the pixels in the coarse positioning image and processing in compensation algorithm to divide the measured object space into narrow zonal areas and obtain the corresponding coarse positioning result image; and superposing the above boundary information onto all the fine grating grey images to be analyzed, non-interlaced traversing, performing quadratic curve fitting and final superposing the extreme points of all the fine grating grey images as the ultimate object space dividing result.

The invention relates to a steel pipe and section steel blanking production line. The production line includes a feed line, a discharge line, and a steel pipe and section steel processing device; the feed line includes a feed roller table, a hydraulic lifting roller table, and a steel pipe hydraulic pressure Lifting roller table, a steel scale is arranged on the feeding frame of the feeding roller table, a positioning block is provided at the zero point of the steel scale, and at least one set of feeding lines is provided on one side of the feeding roller table, and the feeding line It includes a sliding feeding device, a raw material conveying device and a raw material storage device; the discharge line is provided with a discharge roller table, a hydraulic lifting roller table and a steel pipe hydraulic lifting roller table, and one side of the discharge roller table is provided with at least one A group of blanking lines, the blanking line includes a sliding discharge device, a processed part delivery device and a processed part storage device The present invention is provided with a steel ruler on the material delivery frame, and a positioning block is arranged at the zero point of the steel ruler, and the cut material Standing on the zero point, the steel ruler on the transport rack can quickly determine the size of the material to be cut, accurate, fast, and error-free; the hydraulic lifting roller table of the steel pipe can be raised when cutting the steel pipe, and the steel pipe can rotate to achieve the purpose of cutting; The invented production line can cut both steel pipe and H steel, with simple, fast loading and unloading, and accurate cutting.