47 results about "Instrument design" patented technology

The invention discloses a while-drilling electromagnetic wave advanced detection sensitivity analysis method, and belongs to the field of oil-gas exploration and development. The method comprises the following steps: constructing a while-drilling electromagnetic wave advanced detection model, quantifying the influence of different measurement parameters on advanced detection signals, then analyzing the response characteristics of the advanced detection signals, extracting key sensitivity factors, and defining a single-parameter sensitivity function and a multi-parameter coupling sensitivity function; the sensitivity of advanced detection signals is qualitatively and quantitatively analyzed from the four angles of the distance to the interface, the formation resistivity, the interlayer and the stratigraphic dip angle, so that the while-drilling electromagnetic wave advanced detection range is optimized, and the adaptability in the well logging process is enhanced. And meanwhile, the advanced detection second-order sensitivity is approximately solved by adopting a central difference formula, influence factors suffered by advanced detection signals are analyzed from a numerical angle, the interaction of multi-parameter coupling is analyzed, and a scientific basis is provided for electromagnetic wave logging while drilling accurate inversion and instrument design.

The invention discloses an all-fiber vortex interference system and a phase variation measurement method, belongs to the field of optical precision instrument design and test, and aims to realize ultrahigh-precision phase variation measurement by using an all-fiber structure. The vortex interference system comprises a light source module, an optical fiber beam splitting module, an optical fiber sensing module, an optical fiber mode conversion module, an optical fiber mode interference module and an imaging module in sequence along an optical path. The phase variation measurement method is a phase variation demodulation method based on angular Fourier transform, which is provided for the all-fiber vortex interference system. The interferometer provided by the invention does not need a complicated light path alignment step of a traditional interferometer, and the sensitivity of the all-fiber vortex interferometer is further improved.

The application provides a design method and system of a porous balanced flowmeter with a center hole, and belongs to the field of fluid metering instrument design and numerical simulation. The method parameterizes the geometric configuration of a 1+N type balanced flowmeter, constructs a dimensionless parameter system, generates parameter sample points in a design space satisfying constraints, constructs a CFD simulation model, drives a CFD solver to perform flow field simulation calculation, and obtains a massive simulation data set; collects physical calibration experiment data of a standard flowmeter, compares the simulation data with the simulation data of the same standard, and obtains a correction factor; the correction factor is used to correct the simulation data set to obtain a training data set; a design proxy model is constructed, the optimization target of the design proxy model is set based on specific working conditions, and the optimized design proxy model is optimized to obtain optimal dimensionless parameters. The application improves the rationality of the distribution of the center hole and the peripheral hole, and improves the design rationality and efficiency of the flowmeter.

The application provides a kind of intelligent auxiliary getting-up equipment and getting-up method, belongs to the technical field of old people's aid instrument design and manufacture, including backrest plate, bottom plate, lifting unit, handrail unit, folding rocker, leg plate, turntable and main control box;Backrest plate is installed above bottom plate and is located in the upper limb bearing part of bottom plate, lifting unit is installed between backrest plate and bottom plate, backrest plate is lifted by the extension and retraction movement of electric cylinder, and the upper body of old people is lifted;The lower limb bearing part of bottom plate is provided with telescopic handrail unit, the force sensor on handrail unit detects the pressure data of old people's arm on handrail and transmits to main control box, main control box controls the movement of turntable and handrail unit, and helps old people to get up;Handrail unit can drive leg plate connected with lower limb bearing part to move through folding rocker, and help old people to stand with both feet on the ground;Handrail unit and leg plate are linked, can assist more old people to stand stably and safely, the whole equipment structure is compact, the degree of intelligence is high, and it is easy to use.

The present invention discloses an active-passive noise shaping successive approximation ADC, including DAC capacitor arrays DAC1 and DAC2, an active-passive noise shaping module (including a passive integrator PINT1 and a positive feedback active-passive integrator APINT2), a six-input comparator COMP, a successive approximation logic module SAR, a clock generation module CKG, and a reference voltage generation module BGVG. The present invention uses the simplest MOS transistor common source stage structure in the active-passive noise shaping module, combines a low-gain active amplifier with positive feedback, and consumes only tens of microwatts to obtain good noise shaping characteristics, which can increase the number of effective bits by more than 5 bits on the basis of a traditional successive approximation ADC. The invention can be used in low-power, high-precision analog-to-digital conversion scenarios, such as biomedical signal acquisition, high-precision instrument design and other fields, and has good application prospects.

The invention relates to the technical field of thermodynamic property testing, and particularly discloses a multipurpose thermodynamic property demonstration method and a body measuring instrument, the body measuring instrument comprises a steel shell and a heat insulation cavity sealing cover, the outer wall of the steel shell is provided with a parameter display screen and an input panel, and the steel shell is internally provided with a storage cavity; the portion, located on the outer wall of the containing cavity, of the interior of the steel shell is filled with a heat insulation filling material. The instrument designed by the invention adopts the principle of the Boyle's law, so that the defects of a method for measuring the volume of an object by a drainage method can be overcome, the volume of the object can be quickly and conveniently measured without using water, and the problem that the volume of an object which is difficult to be soaked in water cannot be measured by the drainage method is solved; therefore, the instrument can also be used as a demonstration instrument for verifying the correctness of the Boyle's law and exploring the relationship between the temperature, the pressure and the volume.

The invention discloses an auxiliary traction system suitable for an oral endoscopic surgery. The auxiliary traction system comprises an auxiliary supporting second connecting block, a connecting column, a first joint ball, a second joint ball, a bent forceps module, a pressing plate and a connecting plate. By means of the integrated design of the arc-shaped rod, the mouth gag and the mouth opener, the requirement for additional auxiliary personnel is effectively reduced, only one or a small number of medical workers are needed for operation, the operation efficiency is improved, and meanwhile the device has the advantages of being flexible and changeable in joint, convenient to use, high in practicability and the like. The supporting instrument has the advantages that an operator can conveniently open an operation area from different angles, the supporting instrument designed through a double-joint assembly is adopted, the supporting instrument can be linked with an existing endoscopic instrument, the requirement for linkage with the existing instrument is met, the operation mode is improved, the position and form of the supporting instrument are flexibly adjusted, and the operation efficiency is improved. And accurate operation of doctors is facilitated.

1. The name of the design product: water quality instrument box. 2. The use of the design product: used for portable water quality instrument design, which can install various types of water quality instruments inside. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective view.

The present invention relates to the field of medical device design technology, and in particular to a color design method and system for a medical clip applier. The method comprises: acquiring surgical environment information and instrument application functions by collecting application scenario information, and based on the surgical environment information and instrument application functions, determining the selection range of color wheel templates by constructing a color wheel, and performing color sorting to generate application environment gradient color levels and instrument design gradient color levels, and generating a number of standby color groups based on the application environment gradient color levels and the instrument design gradient color levels, performing visual inspection and analysis based on the number of executed color groups, and acquiring a color design scheme for the clip applier. Through the present invention, the influence of surgical environment conditions and surgical site conditions on instrument visibility is effectively solved, and by accurately selecting colors based on surgical environment information and instrument function requirements, surgical efficiency is effectively improved and surgical risks are greatly reduced.

The utility model relates to a weighing instrument of a lifting machine. The weighing instrument structurally comprises a base, a weighing platform and a loading mechanism, the object carrying mechanism is composed of a main frame, a lifting mechanism and a bottom support, the main frame is installed on the weighing platform, the lifting mechanism is fixed to the main frame, and the output end of the lifting mechanism is connected with the bottom support and drives the bottom support to ascend and descend relative to the weighing platform so as to adapt to objects to be weighed of different heights. According to the weighing instrument, the lifting mechanism is integrated, the vertical lifting function is achieved, the flexibility of the weighing instrument is improved, the weighing instrument can be seamlessly integrated into an automatic production line, online weighing is achieved in cooperation with a moving tray, and the automation level is remarkably improved. In addition, the weighing instrument is compact in design and high in adaptability, the size can be telescopically adjusted according to needs, and diversified production line layout requirements are perfectly met. According to the utility model, the lifting function and the weighing function are combined, and an efficient and flexible solution is provided for weighing articles on a production line.

The utility model belongs to the technical field of design and manufacture of isotope magnetic mass spectrometers in analytical instruments, particularly relates to a cavity of an adjustable multi-receiver of a mass spectrometer, and aims to solve the problem that the original adjustable multi-receiver occupies a large space. A front panel, a left panel, a right panel, a rear panel, an upper panel and a lower panel are hermetically and fixedly connected together to form a hollow rectangular cavity; a plurality of left lower connecting holes are formed in the left panel, left lower connecting pipes are mounted on the left lower connecting holes, the left lower connecting pipes are fixedly connected with the left panel, the left lower connecting pipes are in sealed connection with the stepping motors, and one stepping motor is mounted on each left lower connecting pipe; an output shaft of the stepping motor penetrates out of the left lower connecting pipe to be connected with a Faraday cup in the cavity. According to the utility model, the position of the Faraday cup is directly adjusted by using a plurality of stepping motors, and the number of intermediate structures can be reduced, thereby reducing the volume of the cavity.

The present invention provides a transmission line temperature measurement method and system, comprising obtaining NTC resistor resistance data and dividing the obtained NTC resistor resistance data according to a preset resistance voltage division rule to obtain multiple corresponding divided voltage values; calculating the multiple divided voltage values ​​using a preset calculation module to obtain multiple corresponding calculation results; fitting the multiple calculation results using a preset fitting module to obtain a corresponding voltage signal; and determining the corresponding temperature value based on the obtained voltage signal. Based on the straight line temperature-voltage relationship within the operating temperature range, the present invention further develops the design of temperature measurement and control circuits. This design can be completed without digital calibration, thereby simplifying instrument design and commissioning.

The invention relates to the technical field of optical spectrum instrument design, in particular to an infrared light refractive index and transmissivity testing system and method for infrared optical glass, and the system comprises an infrared light source unit, a monochromator unit, a precise angle measuring unit, a general control unit and an upper computer data processing system. Incident light is divided into sample light and reference light through the double-beam light splitting module, the refraction angle and the light intensity of light beams penetrating through a sample are automatically tracked and measured by utilizing the self-positioning aiming mobile table, and meanwhile, an optical path compensation module and a full-automatic temperature control system are combined, so that the aim of measuring the light intensity of the sample within a set broadband and temperature range is achieved. And the refractive index, the reflectivity and the transmissivity parameters of a prism or window sample are subjected to integrated and high-precision synchronous measurement. The technical problems that in the prior art, multiple instruments are relied on, the operation process is complex, efficiency is low, and accurate measurement is difficult to conduct under the variable temperature condition are effectively solved.

The invention discloses a novel activated sludge cyclone separation device which comprises a cyclone cavity and a conical section, the cyclone cavity and the conical section are split, the cyclone cavity and the conical section are spliced through a flange, a tangential feeding pipe is arranged on the side face of the cyclone cavity, an overflow pipe is arranged at the top end of the cyclone cavity and is perpendicular to the center of the top of the cyclone cavity, and the tangential feeding pipe is connected with the overflow pipe. An underflow pipe is arranged at the bottom end of the conical section, the conical section is provided with an upper part and a lower part, and the upper part and the lower part are fixed through a fixing frame. The cyclone cavity (the pre-separation area) and the conical section (the main separation area) are independently designed and spliced together, and the pre-separation area and the main separation area with different size proportions are optimized and coupled according to the separation effect of an instrument, so that adjustment of design parameters of the instrument is facilitated; the tangential feeding pipe is provided with a spiral flow deflector for enhancing the tangential speed; the air column stabilizer improves the light floc enrichment efficiency.

The utility model discloses a light-emitting diode (LED) array light source light following system of a high-flux living cell imager, which relates to the technical field of instrument design and control and comprises an objective table and an LED light source which are relatively fixed, an objective lens moves relative to the objective table, the movement stroke of the objective lens is matched with the LED light source, and the light source light following system is respectively in signal connection with the objective lens and the LED light source. The control module is used for controlling the LED light source to be turned on or off. According to the utility model, the problem of cell phototoxicity is solved by lighting a light source only when the light following system controls imaging, the problem of mismatching of light and an objective lens is solved through the LED array, and based on an array LED circuit principle, the functions of light adjustability, constant current, RS485 control and the like are added, so that the light brightness of the LED array is more stable, and the light intensity of the objective lens is more stable. According to the invention, the LED light source can not change along with factors such as external voltage and temperature, has a more stable light supplement effect, realizes control of stable lighting of each lamp bead at any brightness, and improves the stability of light brightness and the light supplement effect.

The invention discloses a process design collaborative management method, electronic equipment and a storage medium, and the method comprises the steps: disassembling to-be-designed instrument structure data in preset design software into a plurality of first data packets according to components of a to-be-designed instrument, and transmitting the plurality of first data packets to a plurality of corresponding responsibility nodes; the first data packet comprises design information of components corresponding to a plurality of responsibility nodes; component design is carried out based on the design information in the first data packet, a second data packet is obtained, the second data packet is authorized, and the authorized second data packet is sent back to the host node; the second data packet comprises designed component information; and after the completely authorized second data packet is obtained, assembling data in the second data packet to obtain an assembly of each component, and issuing the assembly of each component. Different task nodes can participate in instrument design at the same time, and the data security is improved while the design efficiency is improved.

The application provides a horizontal instrument with constant relative error, and relates to the technical field of horizontal instrument design. The horizontal instrument with constant relative error comprises a base and a main level tube, the main level tube is arranged on the base, the main level tube is provided with a cavity for containing liquid, the top wall of the cavity is a curved surface, the projection of the curved surface on a preset plane is a preset curve, the preset plane is parallel to the length direction of the main level tube, and the equation of the preset curve is as follows: f(x) = a-a·e cx By adopting the arrangement, the horizontal instrument with constant relative error solves the problem that small range and large range can be measured, and the relative error is constant during measurement. The horizontal instrument with constant relative error can be popularized and applied to deformation monitoring of bridges, culverts and aqueducts, and inclination monitoring of geological disasters such as slopes and landslides.

The invention relates to the technical field of medical instrument design, in particular to a medical clip applier color design method and system.The method comprises the steps that operation environment information and instrument application functions are obtained by collecting application scene information, and based on the operation environment information and the instrument application functions, a medical clip applier is obtained; the method comprises the following steps: respectively determining a selection range of a color wheel template by constructing a color wheel disc, carrying out hue sorting, generating an application environment gradient color gradation and an instrument design gradient color gradation, generating a plurality of to-be-executed color groups according to the application environment gradient color gradation and the instrument design gradient color gradation, and carrying out visual detection analysis according to the executed color groups. According to the color design method and device for the clip applier, the influence of the operation environment condition and the operation site condition on the visibility of the instrument is effectively solved, the color is accurately selected according to the operation environment information and the function requirement of the instrument, the operation efficiency is effectively improved, and the operation risk is greatly reduced.

This invention discloses a method for screening and determining the configuration of a gear measurement center in multiple scenarios, belonging to the field of precision testing technology and instrument design. The method takes candidate configurations of the gear measurement center as the object, and sequentially establishes a configuration error score model, a configuration stiffness score model, and a structural compactness score model. The measurement scenarios are divided into small module, medium module, and large module scenarios according to the gear module. Based on the upper bound of the three-dimensional axis depth geometry related to the module, a design domain for the axis depth interval of each scenario is generated, and a unified reference scale for the scenario is determined. An interval hierarchical structure model is constructed, using three types of score intervals as inputs to the scheme layer interval judgment matrix. The criterion layer uses the Saaty scale to construct the judgment matrix, obtaining the global priority interval of the candidate configurations and completing the sorting output. This method can be used for configuration adaptability evaluation and selection of gear measurement centers under multiple scenarios and parameter uncertainty conditions.

The invention relates to the technical field of optical instrument design, and discloses a line-distance-variable grating spectrometer performance and tolerance collaborative optimization method, a spectrometer, a system, a terminal and a medium, and the method comprises the steps: constructing a performance evaluation function of the spectrometer; determining an optimization variable, and obtaining a target optimization result meeting requirements according to the performance evaluation function and the optimization variable; performing tolerance analysis according to the target optimization result to obtain an evaluation result; and determining a design result of the spectrometer according to the evaluation result. According to the method, a strict ray tracing method is adopted to replace an approximation formula, the calculation precision is improved, high performance is pursued, and meanwhile it is ensured that the design scheme has the high yield under existing machining and assembling tolerances.

The present invention relates to a percussion instrument which generates sound by knocking a resonance device. The technical result of the proposed invention is that a complete chord can be produced using one tongue element, each complete chord having its own tongue element, regardless of whether the entire musical instrument is used or the tongue is used individually. This is achieved in that, compared to the prior art, a percussion instrument designed to generate different frequencies has at least one vibrating tongue element with grooves designed to generate different frequencies forming chords. Various embodiments of the tongue element are presented to solve the technical problem of generating a chord.

The invention discloses an optical path system of a ball-borne ultraviolet spectrograph, which belongs to the field of optical instrument design, solves the problems of low broadband efficiency and poor image quality of the existing optical path, and comprises a front-end receiving and transmitting module comprising a light collecting lens (f is equal to 200mm), an ultraviolet enhanced integrating sphere (the reflectivity is greater than or equal to 90%) and an ultraviolet optical fiber; and the rear-end spectrum detection module comprises a slit (10 [mu] m wide), a collimating lens (f = 79 + / -0.4 mm), a reflection blazed grating, an imaging lens (f = 106 + / -0.4 mm) and a back-illuminated ultraviolet CCD (6.5 [mu] m pixel). The lenses are all made of fused quartz or calcium fluoride materials suitable for the ultraviolet band, and other elements are processed through film coating and the like, so that it is guaranteed that an optical path covers 200-400 nm. And a long slit and aberration optimization design is adopted, so that the spatial dimension image quality is remarkably improved. The optical path has the advantages of being wide in wave band, high in luminous flux, high in image quality and high in integration level.

The invention provides an orthopedic implantation instrument design method based on a structure-material-tissue regeneration relationship, which comprises the following steps: S1, acquiring anatomical structure, bone characteristics and mechanical property data of an implantation part of a patient, obtaining structure-material and tissue regeneration quantitative data in combination with an animal experiment, and constructing a data set; s2, based on the data set, establishing a quantitative mapping model among the structure, the material parameters, the biomechanical property and the tissue regeneration effect by using deep learning, and improving the model precision through historical data training and cross validation; and S3, decomposing functional requirements and design parameters by applying axiom design, generating a structure and material scheme which is matched with anatomical features and meets functional requirements through Z-shaped mapping and deep learning reverse optimization, and obtaining a final design of the personalized implant instrument after iterative verification. The method is based on a deep learning data driving model and an axiom design theory, it is ensured that design parameters achieve expected performance, and design accuracy and reliability are remarkably improved.

This disclosure relates to the field of oil and gas exploration, and discloses a drilling azimuth electromagnetic resistivity antenna system structure and logging tool, including: a transmitting coil and a receiving coil; the normal directions of the transmitting coil and the receiving coil are both perpendicular to the drilling direction; the transmitting coil is used to transmit electromagnetic waves to the target formation; the receiving coil is used to receive electromagnetic waves reflected from the target formation. This disclosure overcomes the limitations of other azimuth electromagnetic resistivity measurements in horizontal wells and highly deviated wells, solves the problems of complex instrument design and low radial azimuth detection efficiency, and fully utilizes the accuracy, simplicity, and applicability of dual-transmitter, dual-receiver horizontal coil antenna systems. It achieves a more convenient instrument for radial measurement of azimuth electromagnetic resistivity and a higher standard for radial measurement accuracy, which plays an important role in saving costs and improving measurement efficiency. It can effectively solve the major problems of complex instrument design and operation, time-consuming maintenance, and low radial azimuth measurement efficiency.

Methods and apparatus for producing images of the retina or fundus with improved quality and visualization of its features. This is accomplished by adjustment of specific pupil size, pupil position, detector pinhole size and wavelength parameters of the instrument to give improved image quality as described by a chosen image quality metric. Methods are less complex than adaptive optics and give an improved image in a region of interest and potentially over a larger field of view. Thus, it will be useful in instruments designed for the screening of retinal disease(s). The methodology is applicable to an individual's eye, on the basis of either the group that said individual falls into or measurements of the quality of their eye's optics. As described herein, the settings (including optimum pupil size, pupil position, detector pinhole size and / or wavelength for imaging) can be chosen to give improved the retinal image quality.

The invention provides a physical wave optics demonstration instrument, and relates to the technical field of physics teaching and science popularization instruments.The physical wave optics demonstration instrument comprises a demonstration instrument shell, a demonstration instrument frame and background cloth, a sliding groove is formed outside the demonstration instrument shell, the exterior of the demonstration instrument frame is slidably connected with a first sliding block, and the first sliding block slides on the inner wall of the sliding groove; a steel wire ring is fixedly installed outside the background cloth, the second telescopic rod is connected with a folding fixing assembly, and the folding fixing assembly comprises a first fixing block, a second fixing block and a third fixing block. The device is designed to better show double-slit interference and thin film interference of light rays, the fluctuation property and interference phenomenon of the light are proved through an optical double-slit interference experiment, and the fluctuation property of the light is further verified through a thin film interference experiment.

The present application relates to a kind of vehicle-mounted fish-eye camera MTF test collimating lens, belong to the field of photoelectric testing instrument design.The technical problem of existing vehicle-mounted fish-eye lens transmission function test equipment needing foreign import, high cost of matching equipment is solved.The collimating lens of the present application includes aperture diaphragm, first lens, second lens, third lens, fourth lens, imaging plane arranged in turn along the direction of light propagation;The light emitted by the object arranged at aperture diaphragm reaches imaging plane after first lens, second lens, third lens and fourth lens in turn;First lens is convex-concave positive lens, second lens is concave-convex negative lens, third lens is concave-convex negative lens, and fourth lens is concave-convex positive lens.The vehicle-mounted fish-eye camera MTF test collimating lens of the present application can provide infinite target when used for vehicle-mounted fish-eye lens MTF test, and the collimating lens has large tolerance limit, is easy to process and adjust, has low processing cost and high test efficiency.

The utility model relates to the technical field of precise instrument design, automatic control and safety engineering, in particular to a limiting device for a vertical X-ray diffractometer, which comprises a frame, an angular instrument is fixedly mounted at the center of the front surface of the frame, and a detector arm is fixedly mounted on the front side of the angular instrument. According to the utility model, the problems that the light tube arm and the detector arm are relatively poor in measurement precision and easy to collide with each other when rotating and moving in the current measurement process are solved, expensive and precise parts such as a light tube and a detector can be protected, the maintenance and replacement cost is reduced, accidental collision caused by human errors or software faults is avoided, and the measurement accuracy is improved. The safety level of overall operation is improved, mechanical operation is stable, accidental collision is avoided, the continuity and precision of the measurement process are ensured, the reliability and repeatability of experimental results are improved, abrasion and damage caused by excessive movement and collision are reduced, and therefore the service life of equipment is prolonged, and the rate of return on investment is increased.

According to the lens capsular bag drag hook device provided by the invention, through the structural design of pre-integrating the suture, the drag hook part and the suture needle, the operation safety and operability are remarkably improved; the pre-fixing design of the suture, the drag hook part and the suture needle eliminates the tedious steps of manufacturing the drag hook on site during the operation, shortens the learning curve and ensures the standardization of the instrument; the long needle scheme is matched with the cornea size, repeated puncture caused by insufficient length during intraocular operation is avoided, the short needle scheme is combined with the sleeve design to provide stable guidance, and tissue damage caused by shaking of the needle body is prevented; the size of the drag hook part is optimized and accurately matched with the bag space, and the accidental injury risk is reduced; the sleeve structure enhances the operation hand feeling, the bottom through opening prevents the drag hook from causing obstruction, and the safety is further improved. In conclusion, by means of the integrated and standardized instrument design, the core problems that in the prior art, operation is complex, the injury risk is high, and adaptability is poor are solved.

The utility model discloses a device for comprehensive measurement of an elevator landing door, which belongs to the technical field of safety measurement of elevator equipment and comprises a main body device and a movable sliding block, a touch screen is arranged right above the main body device, a T-shaped force sensor and a detachable cylinder are arranged at the front part of the main body device, the detachable cylinder is provided with protruding external threads, and the movable sliding block is connected with the touch screen. The movable sliding block is fixed with the force sensor through threads, the upper half portion of the force sensor is connected with the electric push rod and the linkage rod, two shifting pieces which are bent downwards and perpendicular are arranged in front of the movable sliding block, the shifting pieces and the force sensor form an opposite extending structure, and the movable sliding block is fixed and connected with the main body device through a sliding rail. The parallel movement of the movable sliding block relative to the main body equipment is realized; the elevator landing door data measuring device has the advantages of being integrated in aluminum alloy instrument design, firm, durable, small in size and convenient to carry, and measuring various elevator landing door data through one device through the detachable cylinder and the customized force sensor.