252results about How to "Increase horizontal resolution" patented technology

A substrate for use in providing an ionized target comprising a structured substrate has a plurality of recesses, at least a portion of the plurality of recesses containing an initiator, the substrate being capable of having a target loaded on it. In one methods, irradiation of the substrate can cause the initiator to restructure, releasing it from the recesses and thereby desorbing and ionizing the target. The target so desorbed and ionized can be detected by mass analyzers. The mass of the targets at a given point on the surface can be recorded to provide a spatial mapping of the targets on the surface.

The invented confocal microscope includes the light source part, the beam splitter mirror, the object lens, the worktable used for placing the sample, the conjugate diaphragm and the first detector. The beam splitter mirror splits the incident light into the transmission light and the reflected light. The conjugate diaphragm is conjugated with the focus point of the object lens. The light source part generates the coherent light. The microscope also includes the reflector. One of the transmitted light or reflected light through the object lens irradiates the sample. The other light irradiates the reflector. The light reflected from the sample passes the object lens, going to the beam splitter mirror where it meets the light reflected from the reflector so as to form the interference figure output from the conjugate diaphragm.

A lens includes a diffractive surface having an etched structure and a refractive surface having a curved structure. The lens reduces chromatic aberration of incident light and extends depth of focus. In one alternative, the etched structure is a calculated phase pattern or a pattern that is embossed or diamond tuned. In another alternative, the curved structure is convex shaped or concave shaped. In yet another alternative, the lens is an imaging lens wherein high lateral resolution of incident light is preserved.

The invention provides a method and device for predicating sand body thicknesses through logging constraint wave impedance inversion. The method includes the steps of acquiring corresponding seismic data and geological logging data after carrying out seismic exploration drilling sampling in a target exploration area, carrying out logging constraint wave impedance inversion on the target exploration area according to the seismic data with the geological logging data as constraint conditions to obtain a logging constraint wave impedance inversion model of the target exploration area, selecting a plurality of sampling points respectively and evenly for each sand group in the target exploration area on an inversion section of the logging constraint wave impedance inversion model to obtain sand body total wave impedance values of corresponding sand groups and sand body thickness relation curves of the corresponding sand groups through fitting, and obtaining the sand body thicknesses of the corresponding sand groups according to the relation curves. The method and device for predicating the sand body thicknesses through logging constraint wave impedance inversion improve reliability of sand body distribution and thickness prediction in stratums with complicated geological conditions, different reservoir stratum thicknesses and large physical property changes.

The invention discloses a method for improving an optical scanning holographic tomography effect, and belongs to the field of optical tomography. The method can solve the defect in the conventional optical scanning technology that restored section images have louder out-of-focus noise, in real time. The method comprises the following steps: utilizing a random phase in the optics encryption technique, changing a certain pupil function in a conventional optical scanning holographic system into a stochastic phase pupil function, and equaling restore of out-of-focus layer images into decryption under the condition of mistakenly decrypting a secret key, thereby enabling the out-of-focus layer images overlaid on the restored section images to be gaussian white noise with statistical independence and greatly reducing the influence of the out-of-focus noise on the focus layer images. Meanwhile the out-of-focus noise can also be filtered through design of a gaussian filter, so that the longitudinal resolution of the system can be improved; besides, through the adoption of the method, the bandwidth of the optical transfer function is wider, and the transverse resolution of the restored section images can be higher.

The present invention relates to two new wave field microscopes, type I and type II, which are distinguished by the fact that they each have an illumination and excitation system, which include at least one real and one virtual illumination source, and at least one objective lens (in the case of type II), i.e., two objective lenses (in the case of type I), with the illumination sources and objective lenses being so positioned with respect to one another that they are suited for generating one-, two-, and three-dimensional standing wave fields in the object space. The calibration method in accordance with the present invention is adapted to this wave field microscopy and permits geometric distance measurements between fluorochrome-labeled object structures, whose distance can be less than the width at half maximum intensity of the effective point spread function. The invention relates moreover to a method of wave-field microscopic DNA sequencing.

The invention relates to underground water detection device and detection method based on the combination of nuclear magnetic resonance and transient electromagnetic method. The underground water detection device is formed by connecting a computer with a transient electromagnetic emission bridge circuit and a nuclear magnetic resonance emission bridge circuit through a high-power power supply with an adjustable output voltage, connecting the nuclear magnetic resonance emission bridge circuit with an emission coil through a harmonic capacitor, connecting the computer with the nuclear magnetic resonance emission bridge circuit and the transient electromagnetic emission bridge circuit through an emission control unit respectively, and connecting the emission control unit with the nuclear magnetic resonance emission bridge circuit and the transient electromagnetic emission bridge circuit respectively. The underground water detection device has the prominent advantages that the limit of a test site is avoided by using a hollow coil, thus increasing the transverse resolution of nuclear magnetic resonance detection. The underground water detection device can be much conveniently applied in underground engineering for narrow spaces such as tunnels and mine excavation roadways, the dimensions of a reception device are greatly reduced, and the spatial constraint is lower, thus the underground water detection device can be used for much accurately detecting a water-containing body; the problems of time consumption, cost consumption and labour consumption during pavement for a large coil are solved, the working efficiency is increased, and the working cost is reduced.

The invention provides an automatic fault interpretation device for a three-dimensional seismic data body. According to the automatic fault interpretation device for the three-dimensional seismic data body, a coherent body imaging module is used for detecting seismic faults, and outputting coherent bodies to depict the faults; an ant colony tracking module performs automatic three-dimensional fault tracking and judgment on the coherent bodies by using a directional ant colony algorithm, and outputs an automatic fault tracking result; an automatic fault separation module is used for judging and automatically separating each fault according to the automatic fault tracking result; and an automatic fault attribute calculation module measures and calculates geometric elements and dynamic attributes of the separated faults. The automatic fault interpretation device for the three-dimensional seismic data body can be used for automatically performing fault interpretation on various seismic data; the device has the advantages of high calculation efficiency, objectiveness and accuracy of fault interpretation results, and the like; and fault interpretation accuracy is effectively improved, and seismic interpretation efficiency is improved.

The invention provides a seismic diffracted wave separating and imaging method and belongs to the field of imaging processing and fracture-cave reservoir prediction in geophysical exploration of petroleum. According to the method, diffracted waves are separated from an original seismic record according to the difference between reflected waves and diffracted waves, and the separated diffracted waves are imaged independently. Diffracted wave information obtained through the method provided by the invention is complete, the diffracted wave imaging result has relatively high lateral resolution, and meanwhile, the result of independent imaging of the diffracted waves eliminates an interference effect on the diffracted waves caused by reflected waves, directly reflects the location information of a fracture-cave reservoir body and is conducive to improving the accuracy of identification of the fracture-cave reservoir body.

To provide an optical imaging apparatus capable of providing a high lateral resolution in a wide region and easily adjusting prior to imaging for imaging an optical image of an eye to be inspected which is an object, and a method for imaging an optical image. The optical imaging apparatus in which a beam from a light source is used as a measuring beam, and an image of an object is imaged based on intensity of a return beam formed of the measuring beam irradiated to the object has the following: first, an optical device for focusing the measuring beam on the object; next, a aberration detecting device for measuring a aberration of the return beam; and a focus adjusting device for adjusting the optical device based on the aberration detected by the aberration detecting device.

The invention relates to a multichannel nuclear magnetic resonance underground water detecting instrument and a field work method thereof. Working parameters of a transmitter and all receivers are configured by a computer, and operating modes of all receivers can be switched between a nuclear magnetic resonance measurement mode and a reference nuclear magnetic resonance measurement mode. Each receiver can connect receiving coils and reference coils, selection of the number of the reference coils can be determined according to a local environmental noise level, and at most eight reference coils can be connected. When the multichannel nuclear magnetic resonance underground water detecting instrument with the reference coils is used, denoising processing is conducted on an obtained nuclear magnetic resonance signal by a self-adaption denoising algorithm, and two-dimension detection on an underground water body is achieved by a multichannel measurement mode. When a transverse resolution of detection is effectively improved, simultaneously signal to noise ratio of the nuclear magnetic resonance signal is improved. The multichannel nuclear magnetic resonance underground water detecting instrument and the field work method thereof are beneficial to conducting nuclear magnetic resonance detection on a detected area under a complex geomorphological condition and a large-noise environment.

The invention relates to a transmitting-receiving antenna separation type nuclear magnetic resonance water exploring device and water exploring method. A computer is connected with a high power supply, a transmitting and control unit, a current collecting unit, a frequency-selecting amplifying unit and a signal collecting unit through serial ports, wherein a control bus is connected with a harmony matching capacitor, a transmitting coil and a diode through an H bridge circuit to form the transmitting and control unit. The water exploring device and water exploring method provided by the invention enable a transmitting antenna and a receiving antenna to be separated, thus a transmitting system and a receiving system can be mutually independent. The water exploring device and water exploring method provided by the invention have the advantages that the high and low voltage separation of transmitting and receiving is realized, thus the reliability of the systems is enhanced; the multiple aspects such as the turn number, dimension, wire diameter, laying type and the like of the transmitting antenna and the receiving antenna are not mutually restricted, thus the amplitude of receiving signals is enhanced, the detecting depth is increased and the detecting speed is enhanced; the far-end reference can cancel interference to enhance the signal-to-noise ratio; and the more comprehensive underground water distribution information can be obtained through three-component measurement, thus the detecting efficiency, accuracy and horizontal resolution are enhanced.

The invention provides a detection device and method for splicing measurement of a surface shape using pinhole diffraction wave front. Light emitted by a laser passes a filtering hole, a first collecting lens, a spatial filter, a beam expanding mirror, a lambda / 2 wave plate, a lambda / 4 wave plate, and an attenuation plate to be transmitted by a beam splitter, reflected by a reflection mirror, subsequently reflected by the beam splitter, and irradiated by a first optical adjusting frame and a second collecting lens set into a pinhole. Partial diffraction light produced by the pinhole is irradiated to a mirror surface to be detected, reflected light of the mirror surface to be detected is reflected by a pinhole frame to produce interference fringes with a part of diffraction wave surfaces of the pinhole, and the interference fringes pass s convergence optical unit and then are collected by an optical detector. The mirror surface to be detected is placed on a second optical adjusting frame and can move along a normal direction of the mirror surface to be detected for annular aperture splicing measurement, and meanwhile, rotation and translation of the first optical adjusting frame can be controlled for performing scanning and splicing measurement on the mirror surface to be detected.

The invention discloses a bolt faying face supersonic wave detection apparatus and a data processing method thereof. The apparatus comprises a mobile platform which is composed of a mobile support and a micro-motion measuring mechanism, and is suitable for measurement of any large-scale bolt faying face. An accurate angular displacement bench in the mobile platform can adjust an angle of an ultrasonic transducer accurately, and detection precision and efficiency are raised. According to the data processing method, a problem of image processing difficulty caused by a measuring result when detecting the bolt faying face is overcome, and a problem of an unsatisfactory image restoration result by employing a traditional Wiener filtering method is solved. According to the method, lateral resolution of an ultrasonic c scanning image is greatly raised.

The invention discloses a device and method of interferometry for a large-scale optical plane. Wherein, the interferometry device comprises an adjustment platform for the two-axis linear motion of an interferometer, a two-dimensional tilt adjustment platform for the measured plane mirror located at the front of the adjustment platform, a laser wave-front interferometer installed in the adjustment platform for the two-axis linear motion of an interferometer and a control computer contained the program of measured data processing algorithm, which is connected to the laser wave-front interferometer. With the device, a plurality of obtained error surface maps of partial region can be spliced to an error surface map containing medium-high frequency (MHF) band on the whole caliber according to the measured data processing algorithm through the control computer, which includes a method for determining the initial position, an algorithm for extracting data from the overlap region and an algorithm for splicing the area data. The invention is a device and method of interferometry for a large-scale optical plane with low cost, high precision and high efficiency.

The invention discloses an intravascular ultrasonic focusing method, focusing diagnostic device and focusing energy transducer. The intravascular ultrasonic focusing method comprises: sending an intravascular ultrasonic focusing diagnostic device to a far-end of a site of lesion; emittingultrasonic signals at 360 DEG to the inside of a blood vessel. The intravascular ultrasonic focusing diagnostic device includes an ultrasonic catheter, awithdrawing / drive apparatus and anelectronic imaging system. The front end of the ultrasonic catheter is provided with the intravascular ultrasonic focusing energy transducer. The rear end of the ultrasonic catheter is connected to the withdraw / drive apparatus which is connected to the electronic imaging system. The intravascular ultrasonic focusing energy transducer includes ultrasonic energy transducer units and a focusing unit. The ultrasonic energy transducer units serve to emitultrasonic signals and receive an ultrasonic signal that is reflected. The focusing unit serves to focus the ultrasonic signalemitted by the ultrasonic energy transducer unit. According to the invention, the resolution of the diagnostic device is increased and the signal to noise ratio of the imaging of the diagnostic deviceis increasedby using intravascular ultrasonic focusing technology, so that the diagnosis precision is increased.

The present invention discloses a three-dimensional imaging laser radar system based on high-speed electro-optic modulation technology. The system mainly comprises a main control circuit module, a laser lighting module, a laser emitting optical system, a laser receiving optical system, a high-speed electro-optic modulation module, an EMCCD imaging module, and a host computer. Under the control of the main control circuit module, the high-speed electro-optic modulation module modulates the echo signal detected by the laser receiving optical system, one path is modulated as an optical signal whose light intensity is monotonically increased with time, and the other path is modulated as an optical signal whose light intensity is monotonically decreased with time. The two modulated optical signals are collected by two paths of EMCCD cameras with photon detection ability at the same time and then are transmitted to the host computer. The host computer processes two images and reconstructs the three-dimensional image of a target scene. The system has the advantages of high imaging speed and high resolution and is especially suitable for the three-dimensional detection imaging of a high dynamic target.

The invention discloses a rapid super-resolution micro-imaging method which comprises the following steps: modulating a first light beam and a second light beam according to corresponding modulation functions; combining the light beams into a path of light by using a beam splitter prism; radiating to the surface of a sample; collecting signal light emitted from different scanning points of the sample to be detected; dividing the signal light into two bundles, wherein the first light beam and the second light beam are imaged simultaneously; controlling the fragrance of the first light beam to be v, by taking the fragrance v as a reference signal, extracting signal light intensity I1(x, y) corresponding to the first light beam from one bundle of the signal light according to the reference signal, and by taking intensity of the other bundle of the signal light as I0(x, y), calculating the signal light intensity I2(x, y)=I0(x, y)-I1(x, y) corresponding to the second light beam, and achieving super-resolution imaging by using final effective signal light intensity I (x, y), wherein x and y are two-dimensional coordinates of the scanning points. The invention further discloses a rapid super-resolution micro-imaging device. As conventional respective imaging of hollow spots and solid spots is converted into simultaneous imaging, the scanning speed is accelerated while the transverse resolution is not changed.

The invention relates to a series resonance mode nuclear magnetic resonance detection device and detection method. According to the series resonance mode nuclear magnetic resonance detection device, a three-component magnetic field measuring circuit is connected with a computer; a high power supply with adjustable output voltage, an emission control unit and a signal collection unit are connected; the high power supply with the adjustable output voltage is connected with a high power emission bridge circuit; the emission control unit is connected with a high-voltage relay; one end of the high-voltage relay is connected with a first receiving unit, and the other end of the high-voltage relay is connected with a Nth receiving unit. By the adoption of the series resonance mode, the size and the weight of a receiving device are greatly reduced, the transverse resolution of nuclear magnetic resonance detection is improved, a small-size receiving probe has better adaptability, and by the adoption of the series resonance mode receiving units, consumed manpower, material resources and time when a large coil is paved on spot are avoided, and working efficiency is improved. A plurality of resonance receiving units which are connected in series in each series resonance mode receiving unit work at the same time, and the amplitude of a received nuclear magnetic resonance signal is improved.

The invention discloses a super-resolution microscope method based on random fluorescence bleaching. The super-resolution microscope method comprises the following steps of: 1, focusing a laser beam on a to-be-detected sample with a fluorescence mark, exciting the to-be-detected sample by the laser beam to emit fluorescent; 2, collecting the fluorescent emitted by the to-be-detected sample to obtain fluorescent strength information; 3, arranging an area-of-interest on the to-be-detected sample, bleaching the area-of-interest, collecting the fluorescent strength information of the fluorescent emitted from the to-be-detected sample in a bleaching process; and 4, comparing and analyzing the fluorescent strength information by a computer to obtain position information of a fluorescent molecule in the area-of-interest, and obtaining a super-resolution image by using a restructing algorithm. The invention also discloses a super-resolution microscope device based on random fluorescence bleaching. The super-resolution microscope device has the advantages of simple structure, high transverse resolution and high signal to noise ratio.

The invention discloses a radial polarized lighting ellipsoidal surface pupil amplitude filtering confocal imaging device which belongs to the optical microscope measurement field. After passing through a collimated beam expander, a polarizer, a radial polarized converter and a spectroscope in sequence, laser beams emitted by a laser of the confocal imaging device are converged onto the surface of an ellipsoidal reflector by an objective lens with large numerical aperture, are returned along a symmetric path after being reflected twice by the ellipsoidal reflector and a sample, and are reflected when passing through the spectroscope again. The reflected beams are firstly converged by a coupling lens, and are transmitted to a photomultiplier through an optical fiber for imaging. The focus of the objective lens with large numerical aperture overlaps with the distal focus F1 of the ellipsoidal reflector; and the proximal focus F2 of the ellipsoidal reflector is located on the surface of the sample. The ellipsoidal reflector is in a zonal structure; the reflectivity of two separated zones is identical; and the reflectivity of two adjacent zones is respectively 0 and 1. By using the confocal imaging device disclosed by the invention, the transverse resolution can be improved, and the ratio of the maximum axial electric energy current density to the maximum radial electric energy current density at the focus can be increased.

The invention provides a multiple visual field stereo display, containing plural equivalent pixels and at least one oblique fence protective screen; wherein the equivalent pixels also contains plural first, second, third and fourth visual angle secondary pixels. The first, second, third and fourth visual angle secondary pixels of the equivalent pixels form a line from left to right in recursive sequence of first, second, third and fourth visual angle secondary pixels; the oblique fence protective screen is provided with plural transparent areas and plural shielding areas, the transparent areas and the shielding areas are in long strip and oblique parallel arrangement, and the arrangement direction of the transparent area is not parallel or vertical to the line. The length-width ratio of the equivalent pixels of the stereo display of the invention is more close to 1, and the transparent area of the oblique fence is provided with an oblique angle, thus improving the lateral resolution of the multiple visual field stereo display, causing the present image picture to be more delicate and reducing interference ripple generated by the display panel and the fence protective screen.

The invention provides a high-resolution photoacoustic imaging method based on multi-angle observation, which comprises the following steps: when a pulse laser irradiates on biological tissues, producing a photoacoustic signal; simultaneously observing the photoacoustic signal by a multi-element array ultrasonic probe, and collecting, storing and uploading all the collected photoacoustic signals to a computer; quickly reconstructing the photoacoustic image on the computer on the basis of a phased dynamic focusing algorithm and a reverse coordinate transformation algorithm; and realizing the multi-angle observation on the biological tissues to be observed by changing dynamic focusing parameters, and carrying out the data fusion treatment on the images observed from different angles. The method realizes the multi-angle observation on the biological tissues to be observed and effectively enhances the lateral resolution and the signal-to-noise ratio of the image; by adopting a distributedquick reconstruction algorithm on the computer, the method increases the imaging speed and realizes the digitalization of the device; and the method realizes the multi-angle and multi-position imagingon the biological tissues to be observed by using the array probe so as to enhance the adaptability and the application range of the system.

The invention discloses a non-linear super-resolution microscopic method adopting photon recombination. The method comprises steps as follows: 1), an illuminating beam after collimation and beam expanding is converted into linear polarization light, the linear polarization light is modulated into circular polarization light and is focused on a fluorescence sample, and hollow light spots are formed for illumination; 2), the fluorescence sample is stimulated to emit saturated fluorescence, and fluorescence imaging is realized by a detector array consisting of multiple photoelectric detectors; 3), the hollow light spots detected by the detectors are subjected to corresponding translation and then are overlaid, an image of a first solid light spot is obtained, and imaging of a corresponding scanning point is realized. The invention further discloses a non-linear super-resolution microscopic device adopting the photon recombination. According to the method and the device, the non-linear effect of fluorescence is realized through high-power laser illumination, a single pinhole detector arranged on an image surface in traditional confocal microscopic imaging is replaced with the pinhole detector array, the photon recombination technology is adopted, the device is simplified, and the imaging speed is increased.

The invention relates to the technical field of medical apparatus and instruments, and provides an OCT (Optical Coherence Tomography) miniature probe, an imaging system and a use method applied to endoscopic high-resolution OCT imaging. The OCT miniature probe is characterized in that the working distance of the OCT miniature probe can be changed through a lens assembly, and the clear aperture of a self-focusing lens is enlarged so as to improve the numerical aperture and the lateral resolution of the OCT miniature probe. According to the OCT miniature probe, the problems of low lateral resolution of the OCT miniature probe in the traditional OCT system and big possibility of deforming of a scanned image can be solved. Therefore, OCT endoscopic scanning imaging with the OCT miniature probe can be applied to human body tissue narrow space, such as blood vessels, digestive tracts and respiratory tracts.

The invention discloses a steel plate full covering supersonic wave detection device, and a method. The steel plate full covering supersonic wave detection device comprises a mechanism capable of walking on a steel plate freely, a multichannel supersonic wave flaw detector, a plurality of probes which are connected with the multichannel supersonic wave flaw detector in corresponding connection andare arranged in linear arrays, a laser movable inductor, a coupling device, a host computer, and a power source; the axis of the probes is vertical to a steel plate plane to be detected; the multichannel supersonic wave flaw detector is used for controlling the probes to send / receive supersonic wave signals, performing analog-to-digital conversion, and sending signals to the host computer; the laser movable inductor is connected with the plurality of probes in linear arrays and the host computer respectively; the host computer is used for obtained real-time two-dimensional position signals from the laser movable inductor for subsequent defect signal analysis, processing, and positioning; the coupling device is used for supplying the probes in linear arrays with a couplant; the power supply is used for providing the multichannel supersonic wave flaw detector, the host computer, and the laser movable inductor with electricity. The advantages are that: detection transverse resolution isincreased, and rapid, accurate, and comprehensive detection of steel plate internal defects is realized based on the limit number of the probes of a conventional portable steel plate detection vehicle.

The invention discloses a measuring method of non-aberration-point sub-aperture stitching for a high and steep convex second non-spherical surface, which divides the measured second non-spherical surface into a plurality of sub-apertures so that the test beam emitted by a surface wave interferometer roughly irradiates a divided first sub-aperture region thereof, measures the surface error of the sub-aperture with the surface wave interferometer under the test condition of non-aberration-point and saves the data, measures the second sub-aperture region and all the remaining sub-apertures in the same way and inputs all the measured data of the sub-apertures to process, and reconstructs the all-caliber face through non-aberration-point stitching algorithm so as to obtain the surface error of the measured second non-spherical surface. The invention needs no non-spherical surface compensator, and is a measuring method for high and steep convex second non-spherical surface with low cost and high precision.

The invention discloses an ocean oil spill detection laser radar system, which uses good transmission characteristics of laser wavebands in seawater to detect underwater submerged oil and perform high-precision detection on targets such as green tide, sea ice, seabed and the like. According to the system, 532 nm and 1064 nm dual-wavelength high-repetition-frequency laser emission is used for carrying out optical active detection on underwater and overwater targets; two-dimensional scanning of laser radar targets is realized by utilizing an optical scanning system, thereby acquiring three-dimensional positions of the targets; in a laser transceiving coaxial design form, the implementation difficulty of the optical scanning system is lowered; a large-caliber, large-view-field and multi-channel optical receiving system is adopted for enhancing the detection capability of underwater relatively weak targets; a signal processing system with a high sampling frequency is adopted for realizingthe target distance detection of the sub-meter precision; a polarization detection channel is adopted for measuring a target surface depolarization coefficient, so that target distinguishing is facilitated; and a laser radar is provided with an airborne mounting device and a shipborne mounting device, so that the use requirements of different carrying platforms can be met.

The invention discloses a single-frame color composite grating stripe reflection mirror surface three-dimensional surface shape measuring method. An experiment system comprises a digital camera, a display screen, a mirror surface to be measured and a computer. The experiment system is adjusted to enable the digital camera to observe the display screen through the mirror surface to be measured, horizontal stripes and perpendicular stripes of different colors are generated simultaneously on the display screen, the digital camera is used for recording deformed stripes through an object with the mirror to be tested, horizontal and perpendicular gradients can be obtained by only projecting one frame of color composite grating stripe to the mirror to be tested throughout the measuring process, and the gradients are integrated to obtain three-dimensional shape information. According to the method, rapid and high-accuracy mirror surface object three-dimensional shape measuring can be achieved.