109results about How to "Reduced precision requirements" patented technology

The invention provides a location method of a partial discharge fault source of a transformer, comprising the following steps: detecting radio-frequency signals generated by a partial discharge source in the transformer by a plurality of sensor modules, and recording the initial time at which a plurality of radio-frequency signals are detected; determining the measured time delay parameters of the radio-frequency signals according to the plurality of the initial time; setting wave speed parameters of the radio-frequency signals; making use of the space mesh division method to search and obtain the location of the partial discharge source according to the measured time delay parameters and the wave speed parameters. In the prior art, the time difference method is very sensitive to parameter errors generated in the transformer actual measurement process, and even tiny parameter errors can lead to problems like method failure or over-great location errors. The method in the invention overcomes the above problems.

The invention provides a system and a method for online recognition of road unevenness. The system comprises a power source module, an acceleration sensing system, a vehicle speed information collecting system, a signal preprocessing module and a road unevenness calculating module. The method includes that road tests are performed on a sample vehicle on two roads different in grade, a linear relation between a quotient of an unsprung mass vertical acceleration mean square value of the vehicle model and vehicle speed and a road unevenness coefficient is demarcated; when the vehicle travels, each unsprung mass vertical acceleration of the vehicle and vehicle traveling speed information are collected; the collected information is compared with a demarcation result of the sample vehicle of the vehicle model, and current road unevenness can be acquired in real time. Compared with current similar technology, the system has the advantages of high transportability, quickness in operation and the like, and is nonsensitive to stiffness damping coefficient change of a suspension and especially suitable for active and semi-active suspension control systems variable in stiffness damping, and robustness of the system can be guaranteed.

An efficient grinding device of a double autorotation grinding disc of a high precision ball comprises a frame, a grinding disc device installed on the frame and a load pressure device; the grinding disc device comprises an upper grinding disc; the load pressure device is installed at the upper end of the upper grinding disc; the efficient double autorotation V-shaped groove grinding device of the high precision ball further comprises an inner disc of a lower grinding disc and an outer disc of the lower grinding disc; the outer disc and the inner disc of the lower grinding disc are coaxially arranged; the inner disc of the lower grinding disc is inserted in the outer disc of the lower grinding disc; a conical grinding surface on the outer side of the inner disc of the lower grinding disc and a conical grinding surface on the inner side of the outer disc of the lower grinding disc form a V-shaped groove structure; the outer disc of the lower grinding disc is fixedly installed on the frame; the upper grinding disc is installed on a rotating shaft; the rotating shaft is connected with a drive motor of the upper grinding disc; the inner disc of the lower grinding disc is installed on a main shaft; and the main shaft is connected with a drive motor of the lower grinding disc. The efficient grinding device of the double autorotation grinding disc of the high precision ball has the advantages of simple structure, low processing cost, higher processing precision and processing efficiency.

The invention discloses a micro power grid wind and solar and energy storage model prediction control method, comprising steps of establishing a prediction model, predicting the maximal output of photovoltaic generation and a wind power set in the micro power grid in the future set time frame by the prediction model, using the predicted the wind power and photovoltaic maximal output as a constraint condition to perform on-line optimization on the output of the wind power set in the micro power grid, the photovoltaic generation and the storage battery to provide reference output, and performing feedback adjustment on the reference outputs of the wind power set, the photovoltaic generation and the energy storage battery according to the real-time adjustable capacity of the wind power set and the photovoltaic generation. Compared with the traditional micro power grid control method, the micro power grid wind and solar energy storage prediction control method reduces the accuracy requirement for the prediction model in the uncertainty process, remedies the defects that the wind power and photovoltaic prediction model is low in prediction accuracy and the high uncertainty in output, and effectively improves the operation characteristics of the micro power grid.

The invention discloses an intelligent inter-row mechanical weeding machine, which comprises a stander, a crop recognizing machine vision system, a sideslip compensation control system, a depth adjusting system and an inter-row weeding device. The intelligent inter-row mechanical weeding machine is towed by a farm tractor to move ahead through the connection between a three-point suspension mechanism on the stander and a three-point suspension mechanism on the farm tractor; the crop recognizing machine vision system is used for collecting row information of crops and position information of each crop; the sideslip compensation control system can adjust the inter-row weeding device to follow the crop rows; the depth adjusting system is used for controlling a depth of a weeding blade tooth in the soil, and profiling land wheels are used for controlling the consistency of the depth of the weeding blade teeth in the soil; and the inter-row weeding device is used for controlling each weeding blade tooth to enter an inter-row area or to get out of the way of the crop. Due to the adoption of the intelligent inter-row mechanical weeding machine, the requirement on the precision of a towing tractor for following the crop rows is low, and the dependence of the inter-row weeding device on the high-precision following of a weeding robot or the towing tractor to the crop rows can be reduced.

The invention discloses a method and device of three-dimension shooting and printing. The method for the three-dimension shooting and printing comprises a step of acquiring a deep point cloud of a target by utilizing a low-precision plane distance measuring device, a step of fitting the deep point cloud into an initial surface, a step of acquiring a color image of the target by utilizing a color photographic device, a step of processing the color image to acquire a human face area and a background area, a step of detecting facial feature points, a step of fitting the feature points of the facial features into a facial curve, a step of modifying a face curved surface included in the initial surface with the facial curve as a standard to improve the precision of the face curved surface and to obtain a modified face curved surface, a step of mapping a color photo to the modified face curved surface to obtain a color three-dimension model of the photographic target, and a step of outputting the color three-dimension model to a three-dimension printer to obtain a three-dimension printing image. According to the technical scheme, face feature information in the color image is fully utilized, the precision requirement for the plane distance measuring device is reduced, and complete automation of the three-dimension modeling process of three-dimension printing is achieved.

The invention discloses a large-field-of-view super-resolution dynamic phase non-lens micro-imaging device and a reconstruction method. The device includes a partially coherent or coherent light source, parallel flat plates, a sample table and a camera which are arranged in sequence to constitute an imaging system. The partially coherent or coherent light source is placed at an uppermost plate ofthe entire imaging system, and the position of the light emission center of the light source is located on an optical axis of the entire imaging system. The device can achieve large stepping and smalldisplacement without any precise sub-pixel displacement device, and therefore the system structure is simplified, the microscope size is reduced, and the cost is greatly reduced; according to the method, the requirement on the mechanical structure accuracy is reduced, great resistance capability to noise in acquired images is achieved, and a large-field-of-view super-resolution phase image can bereconstructed very steadily and accurately.

The invention discloses a flexible alternating current/direct current electronic transformer checking device based on mixed sampling. The flexible alternating current/direct current electronic transformer checking device comprises a primary rising current circuit, a high-precision alternating current AD acquisition circuit, a high-precision direct current AD acquisition circuit, a standard transformer, an I/U converter, a main-control CPU module and a digital value acquisition module; an electronic transformer body to be checked is connected in series with the standard transformer and the primary rising current circuit sequentially through an optical fiber; the standard transformer is connected with the high-precision alternating current AD acquisition circuit; the primary rising current circuit is connected with the high-precision direct current AD acquisition circuit; the high-precision alternating current AD acquisition circuit and the high-precision direct current AD acquisition circuit are connected with the main-control CPU module; a merging unit is connected with the main-control CPU module through the digital value acquisition module; the main-control CPU module also sends synchronous signals to the high-precision alternating current AD acquisition circuit and the digital value acquisition module. Through the adoption of the device, alternating current and direct current checking of the transformer in a UPFC can be realized, the use is convenient, and the application prospect is excellent.

The invention relates to a light path tester, which comprises a shell body, a power supply device, a light signal display circuit, an optical module and a light receiving detection circuit, wherein the optical module is provided with a light input interface and an output level interface; the light receiving detection circuit is connected with the output level interface and the light signal display circuit; the power supply device supplies power to the optical module and the light receiving detection circuit; the optical module further comprises a light output interface and an input level interface for optical signal illumination; and the power supply device, the optical module and the light receiving detection circuit are all accommodated in the shell body. Compared with the existing optical tester, the light path tester adopts qualitative test and indicating lamp display to judge whether the optical signal exists or not, the requirements on test precision, test display and maintenance personnel quality are reduced, the manufacturing cost is far lower than the price of the existing optical tester, the requirement of light path detection can be satisfied, the maintenance cost and investment are also greatly saved, and furthermore, more economic benefit is produced.

The invention discloses a method for manufacturing technics of a bipolar transistor with vertical type and a bipolar transistor with vertical type. The method comprises the following steps: after ion implantation is carried out to obtain an intrinsic base region and a collector region which is under the intrinsic base region, a buffer layer is further deposited; the buffer layer is etched by a single-step dry method to form a side wall; a wet method is adopted to etch and wipe off the film to expose the intrinsic base region; emitter heteromorphic silicon is deposited; an emitter is obtained by chemical wet etching; then an external base is formed by using chemical wet etching again. The invention guarantees the dimensional precision of the emitter, and at the same time has a low requirement for the precision of an etching plate. The invention is simple in technics and cost-efficient.

A non-interference precise locating mechanism for multi-position machining system is disclosed. A following table can move along guide tracks. A leading screw matched with nut is parallelly arranged between two guide tracks. The locating pin on the following table is matched with the locating sleeve tubes on the bottom of bench, which is controlled by a cylinder for moving up and down relatively to the following table. The locating holes at both ends of bench are matched with the locating pins on locating table of working positions. Its advantages are high locating precision, small size, light weight and low cost.

The invention discloses a T-BOX anti-dismantling method and system based on an MD5 dynamic encryption algorithm. The method comprises the following steps: setting private keys for the T-BOX and an ECU; timing the ECU by the T-BOX; randomly generating 8-byte data inside the ECU and sending the 8-byte data to the T-BOX; calculating a key according to the clock by the T-BOX; adopting the MD5 encryption algorithm to obtain a result and sending the result to the ECU by the T-BOX; calculating to obtain a result by the ECU according to the same method for comparison; and comparing the two results, ifthe two results are the same, then judging that handshake verification is correct, and a vehicle works normally, and if the two results are not the same, then waiting for 5 seconds and sending the handshake verification again, if the two handshake verifications are wrong, then performing vehicle locking control on the vehicle by the ECU. The T-BOX anti-dismantling method based on the MD5 dynamicencryption algorithm provided by the invention solves the problems in the prior art that the vehicle cannot be supervised and controlled, and the vehicle is maliciously owed or stolen since the vehicle Internet of Things monitoring terminal, namely the T-BOX, assembled on a financially mortgaged vehicle of the construction machinery industry is maliciously dismantled.

The invention provides an air inlet flow guide pipe, which comprises an air inlet, a first rigid pipeline, an air inlet hose pipe and a second rigid pipeline, wherein one end of the first rigid pipeline is fixedly connected with the first air inlet, the other end of the first rigid pipeline is fixedly connected with the air inlet hose pipe, one end of the air inlet hose pipe is connected with the first rigid pipeline, the other end of the air inlet hose pipe is connected with the second rigid pipeline, and the air inlet pipe is a hollow pipeline which is of a corrugated structure and is formed by spirally winding and welding porous non-woven fabric and fiber fibers in an ultrasonic way. The invention also provides a preparation method of the air inlet hose pipe. The pipeline of the air inlet flow guide pipe is flexible and variable, and is automatically applicable to the clearance difference of the assembly fixing point, so the precision requirement on the assembly fixing point is low, and the assembly efficiency is improved; the contradiction between the layout space and the property requirement of the air inlet pipeline in an engine compartment can be solved by the air inlet flow guide pipe; in the premise of not needing the complicated cavity structure, the good silencing and noise degrading functions are realized, the assembly weight is reduced, and the NVH (noise, vibration and harshness) level of vehicles is improved.

A hollow optical slip ring comprises a stator, a rotor, an input optical fiber channel, an annular inclined optical fiber grating, and an output optical fiber channel. Both the stator and the rotor are composed of annular base bodies, the annular radial outer circles the stator and the rotor are the same, the annular radial inner circles of the stator and the rotor are the same, the axis of the stator and the axis of the rotor coincide with each other, and a hollow structure is formed. A part of the inclined optical fiber grating is arranged in the stator, a full-grating area is engraved on the circumference of the inclined optical fiber grating, when light beams in the input optical fiber channel is shot to the inclined optical fiber grating, the inclined optical fiber grating which is designed with a certain gradient can reflect a part of the input light beams, and reflected light passes optical fibers with a wrapping layer peeled, then is vertically transmitted upwards and enters the output optical fiber channel. The hollow optical slip ring is simple in structure and easy to achieve, the requirement for precision of a mechanical device is not high, and gases, liquids and other flow media can be transmitted in a hollow state.

The invention discloses a resistance high-precision measuring system and method with combination of a differential method and a proportion method. The system comprises a constant current source, a reference resistor, a first differential amplifier, a programmable gain amplifier, an analog-to-digital converter, a microprocessor, a digital-analog converter and a measured resistor interface, the measured resistor interface is connected to a measured resistor, the reference resistor and the measured resistor are connected in series to form a serial connection branch circuit connected between the constant current source and the ground, two input terminals of the first differential amplifier are respectively connected with two terminals of the reference resistor, an output terminal of the firstdifferential amplifier is connected with a voltage reference terminal of the analog-to-digital converter, a first input terminal of the programmable gain amplifier is used for being connected to a to-ground single-end voltage of the measured resistor, a second input terminal of the programmable gain amplifier is connected with an analog output terminal of the digital-to-analog converter or the ground in a controlled manner, an output terminal of the programmable gain amplifier is connected with an analog input terminal of the analog-to-digital converter, and digital output terminals of the analog-to-digital converter and the digital-to-analog converter are both connected with the microprocessor. According to the system, the influence of power supply fluctuation can be overcome, the cost islow, and the measuring precision is high.

The invention discloses an optical fiber beam expanding contact based on a self-focusing lens. The optical fiber beam expanding contact comprises a ceramic sleeve with a lens and a pin flange with a ceramic pin. The ceramic sleeve with the lens comprises the self-focusing lens and the ceramic sleeve. The self-focusing lens is adhered in the left end of the ceramic sleeve, and a gap is left between the self-focusing lens and the left end surface of the ceramic sleeve. The pin flange with the ceramic pin comprises a ceramic pin and a pin flange. The pin flange 4 comprises a first step hole and a second step hole. A bare optical fiber is inserted into the ceramic pin, and the optical fiber and the ceramic pin are connected as a whole. The right end of the ceramic pin is interference-pressed into the second step hole of the pin flange. The right end of the pin flange 4 is provided with a circular hole cavity through which the optical fib passes. The pin flange with the ceramic pin is combined with the optical fiber to form an optical fiber pin body. The right end of the ceramic sleeve is adhered in the first step hole of the pin flange. The ceramic pin is in contact with the self-focusing lens.

The invention discloses a seven-degree-of-freedom space manipulator ground microgravity equivalent experiment device and method, and belongs to the field of space manipulator microgravity simulation ground experiments. The mechanical arm comprises a shoulder suspension supporting frame air foot device B, an elbow support air foot device C, a wrist suspension supporting frame air foot device D, a seven-degree-of-freedom mechanical arm A, a joint suspension shaft device E, an air cylinder device F and an air cylinder device G. The seven-degree-of-freedom mechanical arm comprises a first arm rodA-8, a second arm rod A-9, three rotating joints including a shoulder rotating joint A-5, a shoulder rotating joint A-6 and a shoulder rotating joint A-7, an elbow rotating joint A-4, a wrist rotatingjoint A-1, a wrist rotating joint A-2 and a wrist rotating joint A-3. The shoulder part and the wrist part are of a symmetrical structure. According to the invention, the influence of the seven-degree-of-freedom space manipulator on the attitudes of other satellite loads and equipment in the moving process can be simulated, and the experimental effect of microgravity equivalent simulation of thespace manipulator on the ground is significantly improved.

The invention provides an LED display device. The LED display device comprises a front box body, a rear box body, a display module, a first connecting structure, a positioning sleeve, an accommodatingdimple and a locking piece, wherein the front box body and the rear box body are connected with each other, and the display module is arranged on the front box body; the first connecting structure isarranged between the front box body and the rear box body, the first connecting structure comprises a rotating piece rotatably arranged on the front box body, and the rotating piece comprises a connecting column extending towards the rear box body; the positioning sleeve is detachably arranged on the connecting column, and a position adjusting mechanism is arranged between the positioning sleeveand the connecting column; and the accommodating dimple is arranged on the rear box body, the positioning sleeve is arranged in the accommodating dimple, the locking piece is arranged on the rear boxbody and located between the accommodating dimple and the positioning sleeve. According to the technical scheme, the LED display device solves the problems that a front maintenance LED display screenin the prior art cannot slightly adjust splicing seams and the flatness between display units, the maintenance efficiency of the display units is low, the assembly is easily affected by manufacturingerrors, and the front maintenance cannot be carried out due to the limitation of the point spacing.

The invention discloses a method for measuring ship percussive force. The method is characterized by: installing a sealed steel enclosing box on a bridge pier, dividing a striking meeting area on the steel enclosing box, arranging a square striking meeting box on the striking meeting area, setting a front panel of the striking meeting box as a striking meeting surface, fixedly installing a plurality of X direction, Y direction and Z direction force transducers in array distribution at a back panel, left and right panels and a bottom panel of the striking meeting box respectively, using a ship to strike the striking meeting surface, measuring respective percussive force Fx, Fy and Fz with the X direction, Y direction and Z direction force transducers in the striking meeting box, and calculating total percussive force that the ship strikes the bridge pier through a resultant force formula. The method has the following advantages: the striking meeting box is installed on the sealed steel enclosing box, thus the striking meeting box can floats up and down according to the change of a water level, it is ensured that a striking position of the striking meeting box by the ship remains unchanged, X, Y and Z directions of the striking meeting box are provided with the force transducers, the percussive force of the ship is obtained through a mode of calculating resultant force, and measured ship percussive force is comparatively in accordance with an actual working condition.

The invention discloses a positioning method for single-phase earth fault sections of an isolated neutral system. The method comprises the following steps: firstly, collecting synchronous stable zero sequence current instantaneous values at two ends of the previous section of a to-be-detected line; calculating the difference value of the two synchronous stable zero sequence current instantaneous values; and determining the fault position regions by virtue of the polarity of the difference value and polarities of the two zero sequence current instantaneous values. The method disclosed by the invention can be used for positioning the fault regions for the condition that a transitional resistance is relatively great and the change of length of the line is inconsistent in the system and has a low requirement on the precision of equipment, so that the accuracy of positioning the fault regions is improved.

Provided is a multi-degree-of-freedom industrial robot which can be applied to teaching demonstration. The industrial robot is low in price, superior in performance and simple in structure, a manipulator of the industrial robot has multiple degrees of freedom, and students can perform programming themselves to change the motion state of the manipulator. According to the industrial robot, an 89C51 single chip microcomputer is used as a controller, a direct-current motor is driven by a PWM power amplifier, and the control mode is simple and easy to learn. The manipulator adopts a chute lever design, and the frictional resistance in the control process is greatly reduced. A stepping motor is adopted to drive a screw-nut transmission mechanism to produce linear motion in arm extension and retraction. When an arm and wrist mechanism is driven by a nut to extend and retract, transmission is performed by a common screw. Therefore, the multi-degree-of-freedom teaching robot is light in weight and compact in structure.

The invention relates to the field of radio-frequency power amplifiers, in particular to a method for enhancing linearity and efficiency of a radio-frequency power amplifier, which is realized in a way that: a capacitor is connected to the output end of the radio-frequency power amplifier, and the other end of the capacitor is connected to the ground. As the output end of the radio-frequency power amplifier is connected with the capacitor which is connected with the ground in parallel, the radio-frequency power amplifier is in the Class-F operating state. The capacitor can reduce the even harmonic impedance of the output end of the radio-frequency power amplifier and enhance the odd harmonic impedance; and the change of the harmonic impedance can affect the amplitude-amplitude distortion and the amplitude-phase distortion of the radio-frequency power amplifier as well as the voltage waveform and the current waveform of the output signal, thereby enhancing the linearity and the efficiency of the radio-frequency power amplifier. The method can have the same effect as an LC harmonic oscillation network, eliminates the influence on the efficiency of the radio-frequency power amplifier due to low inductance Q value in the LC harmonic oscillation network, and has the advantages of simple and easy implementation and low cost.

This quantitative powder fetching device comprises of a sliding sleeve with an inside powder inlet groove through it, a sliding hopper with a quantitative groove inside it and pressed by the elastic components to the sliding sleeve to form a siding pair or rotating pair and elastic components, and when the quantitative groove of the sliding hopper connects with the powder inlet groove of the sliding sleeve to let the powder it, a No.1 position of the sliding hopper's moving path is fixed and when the quantitative groove of the sliding hopper separates with the powder inlet groove of the sliding sleeve to discharge the powder, it comes with the No.2 position. Pressing the sliding hopper on the sliding sleeve with proper elastic force, it can not only effectively reduce the gap between them but also maintain the smooth moving of the sliding hopper, so as to make it work and reduce the precision requirement for manufacturing and assembly.

The invention belongs to the field of aerotechnics, and particularly relates to a long-shot optical-train type precision approach course indicator light structure which comprises a light source device, a color filter, a concave lens, a convex lens and a lamp box, wherein the light source device, the color filter, the concave lens and the convex lens are positioned in the lamp box; the lower edge of the color filter, the center of the concave lens and the center of the convex lens are on the same primary optical axis; the distance between the concave lens and the convex lens is smaller than the focal length of the convex lens and greater than the sum of the negative focal length of the concave lens and the focal length of the convex lens; the concave lens and the convex lens constitute the long-shot optical-train with a long focal length; the color filter is positioned at the composite focus of the long-shot optical-train; and rays emitted from the lower edge of the color filter become parallel at the primary optical axis after passing through the concave lens and the convex lens. The invention has the advantages of simple structure and novel concept, and realizes a long-shot optical-train type precision approach course indicator light structure which has the advantages of long focal length, large tolerance of defocusing amount, and easy realization of three-division angle, and solves the problems of high requirements for working accuracy, difficult regulation on light path and difficult realization of three-division angle in the common single-lens precision approach course indicator light.

The invention relates to a method for extracting local salient objects in a depth image based on multi-way tree. The method includes the following steps that: pixel-by-pixel neighborhood difference is performed on an inputted depth image, and a multi-way tree data structure-based depth tree model and a mapping graph of depth tree nodes and image pixels are established; local optimization is performed on leaf nodes of a depth tree, so that noises can be removed; the leaf nodes of the depth tree are traversed, so that a local extremum area of the depth image can be obtained, and the positions of subtree root nodes of the leaf nodes are determined through utilizing a decision function, and therefore, local salient objects areas can be extracted out. With the method adopted, a plurality of salient objects areas can be extracted out quickly and accurately, and the accuracy of the detection of the salient objects in the depth image can be improved.

The invention relates to a method and a device for automatically identifying book pages, which realize automatic positioning of the book page by using an optical character recognition (OCR) technologyand a full-text retrieval technology and are divided into two steps: preparation of a book full-text retrieval database and automatic identification of a page number. By means of the OCR recognitionand retrieval technology for converting positioning of pages into texts, the problems existing in an existing method are solved, the requirement for the precision of OCR recognition is low, and part of text recognition errors cannot affect the overall retrieval result.

The invention discloses an adjustable hanging piece, and relates to the technical field of the use of fixedly installed furniture. The adjustable hanging piece is arranged on a wall for hanging objects, and includes a wall fixing part I, a wall leveling part II, a heightening part III and wall protection panel hanging pieces IV; the wall fixing part I includes a first fixing plate I and a second adjusting plate I; the wall leveling part II includes a first adjusting plate II and a second adjusting plate II; the heightening part III includes a first adjustment plate III, a second adjustment plate III and a third connection plate III; and the wall protection panel hanging pieces IV comprises first fixing plates IV, second fixing plates IV and third connection plates IV. The adjustable hanging piece has the beneficial effects that a metal hanging piece can adjust a wall panel in the front and rear latitudes and the upper and lower latitudes, is low in precision requirements for installation, reduces the difficulty of installation, shortens the installation time, can be used even on an uneven wall, and greatly overcomes the requirements for the wall; and the installation speed is increased, the quality is improved, and the risks that the adjustable hanging piece is not environmentally friendly, air nails need to be driven, the straightness is low, and decay exists are overcome.

The invention relates to a light beam pointing control system based on a conical mirror and a deviation correction method thereof. The invention aims at solving the technical problems that an existinglight beam pointing control system is complex in structure, detector installation position deviation and interference of dust in air have large influences on detection precision, and provides a lightbeam pointing control system based on a conical mirror and a deviation correction method of the light beam pointing control system. According to the light beam pointing control system based on the conical mirror and the deviation correction method thereof, the light beam forms the Bessel light beam after passing through the conical mirror, the angle offset and the position deviation of the laserbeam can be measured respectively, and meanwhile, due to the characteristics of no diffraction and long focal depth of the Bessel light beam, the focal depth of the central focus is far longer than that of a common convex lens, so that the requirement of the system on the precision of the mounting position of the detector relative to the conical mirror is reduced, the interference of dust particles in air on the detector is smaller, the detection result is more stable, the structure is simple and the size is small.

The present invention relates to the field of electronic equipment. A preparation method of a housing comprises the following steps of processing chamfers and/or rounds on first edges of a housing opening, and forming first narrow edges; forming a protection layer on the housing body, and performing first coloring on the first narrow edges; processing chamfers and/or rounds on second edges of the housing opening, and forming second narrow edges; and performing second coloring on the second narrow edges and the housing body. The preparation method of the housing is simple in process, the accuracy requirement is low, the visual effect that edges of a screen are free of frames when a portable electronic device is viewed from the front side can be achieved, and a series of related tests of the whole machine can be satisfied due to the fact that the housing has the narrow edges.

The invention provides an inside and outside grinding machine for a pipe. The grinding machine comprises a working table, a pipe clamp assembly, an inside grinding assembly and an outside grinding assembly. The pipe clamp assembly comprises a pneumatic chuck, the pneumatic chuck is connected to the working table in a rotary mode, and the central axis of the pneumatic chuck is higher than the table face of the working table and parallel to the table face of the working table. The inside grinding assembly and the outside grinding assembly are arranged at the two ends of the pneumatic chuck respectively in a matched mode. The inside grinding assembly comprises an inside grinding wheel and an inside grinding motor, an output shaft of the inside grinding motor is connected with the inside grinding wheel in a rotary mode, and the inside grinding wheel and the inside grinding motor are connected the working table in a sliding mode through a first connecting frame. The outer grinding assembly comprises an outer grinding wheel and an outer grinding motor, an output shaft of the outer grinding motor is connected with the outer grinding wheel in a rotary mode, and the outer grinding wheel and the outer grinding motor are connected with the working table in a sliding mode through a second connecting frame. The inside and outside grinding machine for the pipe has following beneficial effects: the precision requirement that the inside grinding wheel and the outside grinding wheel need to be identical in rotation speed is lowered; and the occupied space of the grinding machine is further saved.