4316 results about "Electro-optics" patented technology

Systems and methods are disclosed for classifying objects using electro-optical and synthetic aperture radar images through multi-modal feature alignment and fusion. A computing system acquires and preprocesses image data, then aligns features across modalities using a multi-modal alignment engine. A cross-modal attention fusion network extracts and integrates complementary information using transformer-based attention mechanisms. A modality-specific feature extraction framework processes EO and SAR images through specialized branches, ensuring optimal feature representation. An adaptive fusion decision system dynamically determines the best fusion strategy based on image quality and confidence scores. A self-supervised consistency controller enforces alignment between EO and SAR features using contrastive learning. The fused representations are processed by a neural network to generate object classifications. This system improves accuracy and robustness in environments where one modality may be degraded or missing, enhancing applications such as remote sensing, surveillance, and autonomous navigation.

The invention provides a liquid crystal composite for an active-matrix-addressed electro-optical display device and application of the liquid crystal composite. The liquid crystal compound comprises a compound with a general formula (I) which occupies 10 percent to 30 percent of the total weight of the liquid crystal composite, a compound with a general formula (II) which occupies 5 percent to 30 percent of the total weight of the liquid crystal composite, a compound with a general formula (III) which occupies 10 percent to 40 percent of the total weight of the liquid crystal composite, and a compound with a general formula (IV) which occupies 10 percent to 60 percent of the total weight of the liquid crystal composite. The liquid crystal composite provided by the invention has a relatively high response speed and good low temperature storage stability. The invention further provides the active-matrix-addressed electro-optical display device comprising the liquid crystal composite.

Various embodiments provide for electro-photonic networks, including a plurality of processing elements connected by bidirectional photonic channels, suited for implementing neural-network models. Weights of the model may be preloaded into memory of the processing elements based on assignments of neural nodes to processing elements implementing them, and routers of the processing elements can be configured to stream activations between the processing elements based on a predetermined flow of activations in the model.

The invention discloses a repetition-frequency-adjustable high-energy nanosecond laser and a working method thereof, and belongs to the technical field of lasers. The laser comprises a synchronizing signal controller, a nanosecond seed source, an electro-optical selection system, a first end face pumping amplification stage, a second end face pumping amplification stage and a side face pumping bi-pass amplification stage, the synchronizing signal controller is adopted to generate a clock reference signal, a frequency division synchronizing signal and a clock synchronizing signal, and integrated control over system signals is achieved. The clock reference signal is used for triggering the seed source to generate nanosecond seed light pulses, the frequency division synchronizing signal is optimized and adjusted to control the electro-optical menu system to screen out frequency division seed light pulses, and the repetition frequency of the seed light pulses is adjustable. Meanwhile, a pulse pumping mode MOPA structure is adopted, the repetition frequency of each amplification stage pumping light pulse and the repetition frequency of the non-frequency-divided seed light pulse are kept consistent through a clock synchronization signal, it is ensured that the heat effect of the whole system is stable, and repetition frequency adjustable nanosecond laser output with high energy and good reliability is achieved.

The embodiment of the invention provides an electro-optical modulator and a light quantum computer. The electro-optical modulator comprises an electrode assembly and an optical waveguide assembly. The electrode assembly comprises a positive signal electrode, a negative signal electrode, a first grounding electrode and a second grounding electrode, and the positive signal electrode and the negative signal electrode are arranged between the first grounding electrode and the second grounding electrode. The optical waveguide assembly is configured to bear optical signals and comprises a first optical waveguide and a second optical waveguide, the first optical waveguide is located between the positive signal electrode and the negative signal electrode and used for bearing first optical signals, and the second optical waveguide is located between the first grounding electrode and the positive signal electrode or between the second grounding electrode and the negative signal electrode and used for bearing second optical signals. The carrier is used for bearing second optical signals. Constant-amplitude voltage signals with opposite phases are applied to the positive signal electrode and the negative signal electrode which are tightly coupled, so that the modulation efficiency can be improved, and the common-mode noise can be reduced.

A burst-mode optical receiver for an optical line terminal (OLT) of a passive optical network (PON) comprises a variable optical attenuator (VOA), a photodiode (PD) which may be a pin-PD or an APD, a transimpedance amplifier (TIA), and a feedback / control circuit for adjusting a bias voltage of the VOA in response to a burst-mode optical input signal level, to provide an attenuated optical output signal to the PD having a narrower dynamic range. Providing signal level adjustment in the optical domain mitigates the requirement for a burst-mode TIA with a large dynamic range and provides for fast switching. The burst-mode optical receiver may comprise a waveguide configuration, wherein a first electro-absorption modulator (EAM) is operable as the VOA and a second EAM is operable as the photodiode. A monolithically integrated electro-photonic circuit comprising the VOA, PD, TIA and feedback / control circuit may be provided using InP-based semiconductor materials.

Apparatuses, systems and methods for optical coupling, optical integration, electro-optical coupling, and electro-optical packaging are described herein. Optical couplers may comprise various optical elements (e.g., mirrors as described herein) to relax optical assembly requirements and improve producibility. Optical couplers may improve fiber-to-chip, fiber-to-fiber and chip-to-chip optical connection. Optical couplers and optical components may be used to improve integration of, connection of, and / or packaging of optical systems and / or components with electrical systems and / or components.

The invention belongs to the technical field of inertia evaluation, and discloses a direct current delivery system minimum inertia demand evaluation method considering multi-frequency modulation resource support characteristic difference, and the method comprises the steps: firstly analyzing the frequency response characteristics of each frequency modulation resource in a direct current delivery system in a typical control mode; a system frequency response model considering wind power, photovoltaic and extra-high voltage direct current frequency response characteristic differences is established, and an influence mechanism of different frequency modulation resources on system frequency characteristics is disclosed. Secondly, constructing a system equivalent inertia calculation model considering a wind power and photovoltaic inertia support effect, and providing a minimum inertia demand evaluation method based on an initial frequency change rate as a constraint; and then, considering the influence of a direct current frequency limit controller on the maximum frequency deviation, designing a direct current delivery system minimum inertia evaluation scheme considering the frequency dynamic safety constraint so as to support efficient, stable and continuous delivery of new energy power generation.

The new media exhibit a ferroelectric nematic phase preferably at ambient temperature. They preferably comprise one or more compounds selected from the group of compounds of formulae IA, IB and IC,in which the variable groups have the meanings indicated in the text and in the claims. Use of the media for providing ferroelectric nematic materials and a method of operation of an electro-optical device are presented. The media may be useful for energy-saving displays and electrical appliances.

An adaptive modular multimodal communication and computing panel includes a multilayer stack with a protective layer transmissive in selected bands, a reconfigurable communication layer operable in phased array, reflectarray, hybrid phased reflector, free space optical, or quantum modes, and electronics with heterogeneous processors. A multi scale interconnect and input and output fabric couples electrical, radio frequency, guided optical, and free space optical domains through interfaces including electro optic transduction and RF or baseband conversion. The fabric may implement programmable true time delay, resonators, and comb referenced timing. A management system coordinates beamforming, sensing, routing, calibration, workload placement, and security. Panels tessellate and connect by electrical, radio frequency, and fiber optic interfaces, supporting hot swappable modules, blind mate connectors, robotic servicing, and anti tamper features. Power and thermal subsystems harvest, store, regulate, and dissipate energy. The architecture scales from chip level modules to vehicle, airborne, maritime, orbital, and deployable systems.

The invention discloses a micro-grid park integrated energy system planning method and device, a terminal and a medium. The method comprises the following steps: acquiring energy demand data, time-of-use electricity price information, natural gas price and meteorological information of a park to be planned, and equipment parameters, equipment investment cost and equipment maintenance cost in an integrated energy system of the park to be planned; the influence of temperature change on thermodynamic characteristics of steam is considered, and equivalent energy storage of a steam heat accumulator of the microgrid park is modeled by considering valley electricity heat storage; setting constraint conditions of a planning model according to the acquired data information, and taking the minimum comprehensive cost as an objective function, thereby constructing a cold-hot electro-optical storage and charging integrated microgrid park planning model considering electric power-steam multi-energy complementation; and solving the planning model, and outputting a planning scheme about whether each device in the integrated energy system is configured, the configuration capacity and the operation output curve of each configured device. According to the invention, the energy structure of the park is optimized, the resource utilization efficiency is improved, and the stability of the system is enhanced.

The invention discloses a multi-sideband chirp modulation DAS system and a working method thereof, and relates to the technical field of distributed sound wave sensing. The DAS system comprises a narrow linewidth laser, an optical fiber coupler, a phase modulator, an electro-optical modulator, an erbium-doped optical fiber amplifier, an optical fiber circulator, a dense wavelength division multiplexer, a photoelectric balance detector, a data acquisition card, an arbitrary waveform generator, a direct current source and the like. The phase modulator is used for modulating constant-amplitude multi-frequency continuous light, the frequency number of light waves is related to the harmonic number of a microwave modulation signal, the frequency interval is determined by the fundamental frequency of the microwave modulation signal, the continuous light frequency can be flexibly modulated by adjusting the microwave modulation signal, and the modulation bandwidth is large; detected beat frequency signals are compressed into single-frequency signals through pulses, phase information of the single-frequency signals is demodulated, vibration signals along the sensing optical fiber can be detected, the spatial resolution of the system depends on the chirp frequency sweeping range, and the spatial resolution is high.

The invention provides a broadband tunable low-phase-noise photo-generated microwave signal source and device, and relates to the technical field of photo-generated microwaves. According to the invention, a low-frequency optical pulse and a high-frequency microwave signal are respectively input into the electro-optical sampling phase-locked loop; and the electro-optical sampling phase-locked loop determines the synchronization error of the optical pulse and the microwave signal based on the phase difference between the optical pulse center point and the microwave signal zero crossing point. And taking the synchronization error as a feedback signal, and continuously adjusting the frequency and the phase of the microwave signal by the voltage-controlled oscillation module until the frequency and the phase are synchronized with the Nth harmonic of the optical pulse. By setting different initial frequencies of the voltage-controlled oscillation module, microwave signals with different integral multiple optical pulse frequencies can be obtained, and broadband tuning of photo-generated microwave signals is realized. Furthermore, the repetition frequency of the frequency comb is locked through beat frequency of two beams of reference laser and two adjacent comb teeth, the stability of the reference laser is transmitted to the optical pulse, and the stability of the reference laser is further transmitted to the microwave signal through synchronization of the optical pulse and the microwave signal, so that the phase noise of the photo-generated microwave signal source is reduced.

The invention discloses a distributed feedback laser and a preparation method thereof, and relates to the field of lasers. The preparation method of the distributed feedback laser comprises the following steps: forming a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an upper limiting layer, a grating layer, a grating buried layer, a corrosion stop layer, an InP cladding, a barrier gradient layer, a contact layer and a sacrificial layer on a substrate, wherein the sacrificial layer comprises an InP layer and an InGaAs layer which are stacked in sequence; etching to form a ridge waveguide structure; forming an insulating layer; removing the insulating layer in a preset area on the ridge waveguide structure to expose the sacrificial layer; wherein the side wall of the InGaAs layer is completely exposed, and the side wall of the InP layer is partially exposed; and etching to remove the InGaAs layer and the InP layer to form an upper electrode layer and a lower electrode layer. According to the invention, the reliability and the electro-optical conversion efficiency of the distributed feedback laser can be improved.

The invention discloses a rapid polarized light acoustic imaging device which comprises an excitation source, a light beam shaping module, a rapid polarization modulation module, an energy feedback module, a rapid scanning module and an acquisition processing module. And receiving photoacoustic signals corresponding to the exciting light in four different polarization states for calculation, and extracting anisotropy information of the sample. Compared with multiple times of scanning a sample or modulating the polarization state by rotating a half-wave plate, the problems of dislocation of multiple times of polarization acquisition points and false positive calculation are avoided, meanwhile, the time interval generated by continuously modulating the laser pulses is short, and energy fluctuation among the four pulses and errors caused by fluctuation are reduced. According to the invention, the limitation of the precision and speed of polarized light acoustic microscopic imaging is overcome, the microstructure characteristics in the target sample can be rapidly, accurately and highly sensitively detected, and the method has great application prospects in biomedical imaging and high-precision material detection.

The invention discloses an optical memristor, and relates to the field of photon integrated circuits and optical computing, and the optical memristor comprises a waveguide layer, a ferroelectric film layer, an electrode structure and a substrate. The ferroelectric film layer is located on the upper surface of the substrate; the waveguide layer and the electrode structure are located on the upper surface of the ferroelectric film layer; the waveguide layer is used for propagating an incident light signal and performing amplitude modulation on the incident light signal; the electrode structure is used for applying an electric field to the ferroelectric film layer; and the ferroelectric film layer is used for carrying out phase modulation on optical signals transmitted in the waveguide layer under the action of the electric field. The ferroelectric material is used as the optical switch of the optical memristor, efficient modulation of the optical phase is achieved through the non-volatility and the high electro-optical effect of the ferroelectric material, and meanwhile the optical memristor has the advantages of being low in energy consumption and rapid in response.

The invention belongs to the technical field of optical communication, and particularly relates to a high-integration-level direct insertion type circular active connector optical cable assembly which comprises a modified connector, a shell connected with the assembling end of the modified connector, a printed board assembly fixedly arranged in the shell and an optical cable assembly. The printed board assembly comprises a rigid printed board I which is in welding fit with a pin contact element in the modified connector, and two end parts of the rigid printed board I are connected with flexible printed boards. According to the high-integration-level in-line circular active connector optical cable assembly in the technical scheme, the photoelectric / electro-optical conversion chips mounted on the rigid printed board II are all vertical emitting light and vertical receiving light, and the photoelectric / electro-optical conversion chips are coupled by adopting the lenses, so that on one hand, the lenses play a role in protecting the photoelectric / electro-optical conversion chips and the gold wires, and on the other hand, the optical cable assembly is not damaged; on the other hand, the optical path can be rotated by 90 degrees to be parallel to the second rigid printed board, it is guaranteed that the optical cable center line and the active electric connector optical cable assembly are located on the same center line, and coaxial fiber output is achieved.

The invention discloses an optical frequency comb generation method and device based on Brillouin scattering and an electro-optical modulator, and belongs to the field of photoelectric measurement. The method comprises the steps that a first laser and a second laser are used for generating pump light and seed light respectively, multi-wavelength pump light is generated through a cascade electro-optical modulator, the pump light and the seed light are emitted into a Sagnac loop, an optical frequency comb is output through the forward Brillouin scattering effect of an optical fiber and the electro-optical modulator, and the seed light and the pump light are output. The polarization controller is adjusted to optimize polarization state matching of the pump light and the seed light, so that the Brillouin scattering effect reaches the maximum value. The device is composed of a laser, an electro-optical modulator, a signal generator, an optical amplifier, an optical isolator, an optical coupler, a polarization controller and an optical fiber. The optical fiber forward Brillouin scattering effect and the electro-optical modulator are combined, the optical frequency comb giving consideration to the wide frequency spectrum and the narrow interval is generated, meanwhile, the comb tooth interval of the optical frequency comb can be accurately controlled by independently adjusting the frequency of the signal generator, and accurate measurement of signals or objects is achieved.

The invention discloses an ultra-low phase noise microwave signal generation method and system based on an electro-optical comb. The method comprises the following steps: 1) locking two lasers with continuously tunable wavelengths in the same FP cavity through two links with different modulation frequencies to realize a dual-wavelength laser with a frequency interval of (v2-v1); 2) reducing the electronic noise of each link to a quantum noise limit by using a residual amplitude modulation noise control technology; 3) coupling the lasers with the center frequencies of v1 and v2 into one path, inputting the laser into an electro-optical frequency comb generator, and generating two sets of electro-optical frequency combs with spectrum overlapping; (4) beat frequency signals of the two electro-optical frequency combs are obtained; the beat frequency signal and a reference signal from a reference signal source are accessed to a phase discriminator for phase discrimination; an output signal of the phase discriminator is sent to a proportional-integral-differential control circuit; and 5) controlling the phase noise of the radio frequency source by using the output feedback of the proportional-integral-differential control circuit to obtain an ultra-low phase noise microwave signal.

The invention discloses a laser coaxial beam combining system for improving the repetition frequency of laser pulses, which comprises p polarization pulse lasers, a pulse time sequence controller and n stages of beam combining devices, each stage of beam combining device comprises an s polarization pulse laser, a polarization beam combiner and an electro-optical Q switch, and n is a non-negative integer and is greater than or equal to 1. The invention has the following advantages: a plurality of beams of laser in different polarization states can be combined, the pulse repetition frequency and the output average power of the laser are improved, the optimal pulse energy and peak power are maintained, and coaxial output of pulses in the same polarization state is realized.

The invention relates to a 4-amino-1, 2, 4-triazole nitrate second-order nonlinear optical crystal material and preparation and application thereof, the chemical formula of the crystal material is (C2H5N4) (NO3), the crystal material belongs to a monoclinic system, the space group is Cc, the cell parameters are # imgabs 0 #, alpha = gamma = 90 degrees, beta = 94.4-98.5 degrees, Z = 4, and the cell volume is # imgabs 1 #. The crystal material disclosed by the invention has a relatively strong frequency-doubled effect, and the frequency-doubled effect is about 3.50 times that of a KH2PO4 (KDP) crystal. Besides, the crystal material has relatively large birefringence of 0.13 at 546 nm and relatively short ultraviolet transmission cut-off edge of 241 nm, and has wide application prospects in the fields of nonlinear optics, electro-optical modulation, photorefractive information processing and the like.

Disclosed in the present invention are a photoelectric terahertz hyperspectral imaging system and method based on a swept-frequency dual-comb. The system comprises: a swept-frequency laser, a distributed feedback laser, a dual-comb generation module, a coupling beam splitter, a spectrum analyzer, a variable optical attenuator, a terahertz mixer, an off-axis parabolic mirror group, a zero bias detector, an electric amplifier and a signal analyzer, wherein the tunable distributed feedback laser is mixed with electro-optical dual-comb light to generate a swept-frequency terahertz dual-comb signal, point-by-point imaging of an object is realized by means of grid scanning, the swept-frequency dual-comb breaks the trade-off between a spectral bandwidth and a frequency resolution in a dual-comb system, and a frequency resolution of 50 MHz is achieved under a spectral bandwidth ranging from 220 GHz to 320 GHz. Scanning dual-comb terahertz imaging has a higher data collection rate, a more flexible spectral tuning range and a higher frequency resolution at room temperature, and the system is flexible and configurable, and has a simple structure and a high detection efficiency.

The invention provides a bent waveguide structure, an electro-optical modulator and a light quantum computer, and relates to the technical field of electro-optical modulation.The bent waveguide structure comprises an input waveguide, a bent waveguide and an output waveguide which are sequentially connected, and the bent waveguide comprises a substrate transmission waveguide layer, an input coupling part and an output coupling part; the input coupling part and the output coupling part are arranged at the two ends of the substrate transmission waveguide layer respectively, a shallow etching groove is formed between the input coupling part and the output coupling part, the input coupling part is connected with the input waveguide, and the output coupling part is connected with the output waveguide. Compared with the prior art, the shallow etching groove is formed between the input coupling part and the output coupling part, so that the thickness of the waveguide film at the bending part is reduced to ensure that the substrate transmission waveguide layer is of a single-mode structure, the transmission loss is reduced, and the bending waveguide is relatively independent from the input waveguide and the output waveguide, so that the transmission efficiency is improved. Therefore, the process precision of the bent waveguide can be independently adjusted, the process time is reduced, and the efficiency is improved.

Electro-photonic integrated circuits comprising optical transmitters and receivers are disclosed, wherein a monolithically integrated electro-absorption modulated laser (EML) is operable bidirectionally, in a transmitter mode and in a receiver mode. Vertically stacked waveguides are provided for a laser and an electro-absorption modulator (EAM). The laser and EAM are optically coupled using a laterally tapered vertical optical coupler. The EML comprises monolithically integrated electronic circuitry, e.g., driver and control electronics for the driving the laser and EAM as an EML, in transmitter mode. The control circuitry comprises a transimpedance amplifier (TIA). The EAM has first and second parts that can be independently biased. In receiver mode, the laser current is reduced to close to the threshold, and a first part of the EAM is biased to absorb residual laser light, and the second part of the EAM acts as a photodiode receiver to provide a photocurrent to the TIA.

Nonlinear optical chromophores having one or more diamondoid groups covalently attached to the chromophore, methods of making nonlinear optical chromophores, their use in thin films and electro-optical devices containing such nonlinear optical chromophores and thin films comprising the same.

The invention discloses an electro-optical-acoustic cooperative partial discharge detection device and method, and belongs to the field of equipment discharge fault detection. The device integrates a high-frequency current detection module, a photoelectric coupling detection module and an acoustic emission detection module; a high-frequency pulse current signal of a cable grounding loop, a pulse electric field of an insulating surface and an ultrasonic signal in a solid medium can be collected at the same time; all the collected signals are sent to the signal integrated processing module for alignment, noise reduction and multi-signal homologous conformity test; after detection, the signal integration processing module extracts combined feature vectors from the signals and inputs the combined feature vectors to the classification discriminator; finally, the discriminator outputs the probability of partial discharge, and if the probability exceeds a preset threshold value, it is judged that partial discharge exists in the cable. Therefore, by implementing the method and the device, the problems that single-mode detection in the prior art is poor in anti-interference capability in a complex field environment, and false alarm or missing alarm is easy to occur can be solved.

An electro-optical device is fabricated on a semiconductor-on-insulator (SOI) substrate. The electro-optical device comprises a silicon dioxide layer, and an active layer having ferroelectric properties on the silicon dioxide layer. The silicon dioxide layer includes a first silicon dioxide layer of the SOI substrate and a second silicon dioxide layer converted from a silicon layer of the SOI substrate. The active layer includes a buffer layer epitaxially grown on the silicon layer of the SOI substrate and a ferroelectric layer epitaxially grown on the buffer layer. The electro-optical device further comprises one or more additional layers over the active layer, and first and second contacts to the active layer through at least one of the one or more additional layers. Methods of fabricating the electro-optical device are also described herein.

The invention relates to an integrated microcavity optical comb repetition frequency and optical frequency locking device and method, and belongs to the technical field of integrated microcavity optical combs. The locking device comprises a pumping module, a power amplification module, a phase modulation module, an electro-optic driving module, an acousto-optic modulation module, an acousto-optic driving module, a band-pass filtering module, a micro-ring resonant cavity and a beam splitting module; the device comprises a soliton detection module, a control module, a repetition frequency detection module, a first feedback control module, an acetylene frequency stabilized laser, a beat frequency module, an optical frequency beat frequency detection module and a second feedback control module. The locking device can achieve full frequency locking of the microcavity optical comb, has the advantages of being high in frequency stability, wide in servo bandwidth, simple and compact in structure, tight in locking, low in noise, high in reliability and low in cost, and can provide a powerful tool for the field of precision measurement.

Disclosed in the present invention are a dual electro-optic frequency comb-based laser tracking interferometric spatial coordinate measurement system and method. Multiple target mirrors are identified by means of a vision module, to guide a rotating mirror to direct laser light toward each target mirror individually. A laser tracking interferometric ranging module obtains a tracking error of the laser beam deviating from the center of the target mirror to be used for closed-loop tracking control. A light source module outputs single-frequency laser light traceable to a gas absorption peak. By controlling a light source modulation module to enable or disable an electro-optic phase modulation drive signal, dual electro-optic frequency combs or dual-frequency continuous-wave laser light is outputted. In a tracking state, the laser tracking interferometric ranging module respectively uses the two light sources to measure the absolute distance and the relative displacement of a target mirror, and the real-time distance between the target mirror and an original point is computed by means of distance fusion; the elevation angle and the azimuth angle of the target mirror are obtained in real time by means of an azimuth angle and elevation angle measurement module; tracking control and coordinate computation are carried out by means of a tracking control and signal processing module and a computer, and finally three-dimensional spatial coordinates of all the target mirrors are measured.

The invention relates to the technical field of lighting electrical testing, in particular to a lamp testing system and method, and the system comprises an electrical parameter collection module, a harmonic analysis module, an optical collection module, a light fluctuation analysis module and an abnormality judgment module. Wherein the electrical parameter acquisition module is used for acquiring a real-time voltage waveform of an input end of a lamp; the harmonic analysis module is used for extracting a fundamental wave and each harmonic component and calculating a harmonic distortion rate; the optical acquisition module is used for synchronously acquiring light signal time sequence data of the light emitting surface of the lamp; the light fluctuation analysis module calculates the light fluctuation frequency of the light source; and the abnormity judgment module is used for generating an electrical-optical relevance index and comparing the electrical-optical relevance index with a preset threshold value so as to output a stroboscopic qualification judgment result of the lamp. According to the method, the accuracy of lamp stroboscopic detection and the causal identification capability are effectively improved by constructing the electrical-optical correlation index and realizing synchronous judgment.