204results about How to "Small signal attenuation" patented technology

The invention relates to impulse response analytical test apparatus and method for detecting deformation of transformer winding, belonging to the technical field of transformer winding detection. The apparatus mainly comprises an impulse generator, a broadband digital oscilloscope, a computer, a high-voltage probe, a head end signal impedance matching device, a tail end signal impedance matching device and a screened coaxial cable. In the method, site test and analysis are carried out by using the apparatus. The invention has the advantages of high test sensitivity, rapid detection, strong capacity of resisting disturbance and flexible analytical method, and can detect slight deformation of the transformer winding and judge early potential faults effectively with high judging accuracy. The invention can be widely applied to the detection of the deformation of the transformer winding and the state overhauling.

The invention provides a liquid crystal phased array-based laser radar system, and relates to the technical field of laser phase control. By the liquid crystal phased array-based laser radar system, the problem that incident light and emergent light are separated by a light splitter in an existing light path and the light intensity loss can be caused by introduction of the light splitter so that the application of a beam deflection system is limited are solved. The liquid crystal phased array-based laser radar system comprises a central processing unit, a laser emission system and an echo receiving system, wherein the laser emission system comprises a laser A and an emission light path, the emission light path comprises a beam expansion collimation system A, a refined deflection system, aone fourth wave plate and a rough deflection system, the refined deflection system comprises a one second wave plate, a liquid crystal spatial light modulator (LCSLM) and a DSP controller, the rough deflection system comprises a liquid crystal polarization rotator, a liquid crystal spatial light modulator (LCPG) and a polarization grating controller, and the echo receiving system comprises a fieldprogrammable gate array (FPGA), an MPPC and a receiving light path. An oblique incidence mode is employed, an included angle between light irradiating the liquid crystal spatial light modulator and emergent light is increased, the light path is simplified, the system volume is reduced, the light intensity loss caused by the light splitter is also reduced, and the application range of the liquid crystal spatial light modulator is expanded.

The invention relates to a squeeze head used for a rock conventional triaxial test acoustic emission test and belongs to the technical field of geotechnical engineering. The squeeze head comprises an upper squeeze head and a lower squeeze head, wherein the upper squeeze head and the lower squeeze head are arranged on a rock message delivery system (MTS) conventional triaxial compression test machine. Round grooves are formed in the lower end face of the upper squeeze head and the upper end face of the lower squeeze head. Two perpendicular installation holes are symmetrically formed in the bottom of each round groove. Perpendicular conductor holes are formed in bottoms of the installation holes. Horizontal conductor holes are formed in side walls of the upper squeeze head and the lower squeeze head, and the perpendicular conductor holes are communicated with the horizontal conductor holes. Springs are arranged at the bottoms of the installation holes. Cover plates are arranged on the round grooves and shapes and sizes of the cover plates are identical to shapes and sizes of the round grooves. By means of the squeeze head used for the rock conventional triaxial acoustic emission test, attenuation and distortion of emission signals can be reduced to the maximum extent, the situation that an acoustic emission sensor is immersed in hydraulic oil is avoided, the acoustic emission test of high confining pressure can be carried out and the facture surface of rock can be positioned.

The invention discloses a long-term monitoring apparatus for a soil pressure outside a duct piece of a shield tunnel. The long-term monitoring apparatus is composed of a fiber grating strain brick, a fiber grating temperature compensation block, a cable box, and an armored cable. The fiber grating strain brick consists of a measuring stone and a mortar layer coating the outside of the measuring stone; and four fiber gratings are arranged at each of three surfaces, being perpendicular to each other, of the measuring stone. The fiber grating temperature compensation block includes a hollow metallic cylinder and a temperature compensation stone arranged inside the metallic cylinder; the space between the temperature compensation stone and the metallic cylinder is filled with EVA foam; and four fiber gratings are arranged at each of three surfaces, being perpendicular to each other, of the temperature compensation stone. In addition, the invention also discloses a long-term monitoring method for a soil pressure outside a duct piece of a shield tunnel. Using the apparatus and method disclosed by the invention, the soil pressure monitoring error can be reduced; and the installation survival rate can be improved. Moreover, the apparatus and method have characteristics of good anti-electromagnetic-interference and corrosion-resistant performances and low signal attenuation; and the soil pressure outside a duct piece of a shield tunnel can be monitored accurately for long time.

Provided is a high-temperature-resistant low-loss compound insulation coaxial cable. The high-temperature-resistant low-loss compound insulation coaxial cable is characterized in that a solid or stranded inner metal conductor (1), a polytetrafluoroethylene micropore compound insulation layer (2), an outer conductor (3) and a sheath layer (4) are arranged from inside to outside in sequence, the solid or stranded inner metal conductor (1) longitudinally extends along the central axis of the cable, the outer conductor (3) is formed by knitting metal or is additionally provided with an inner shielding layer, the sheath layer (4) is made of FEP copolymer or low-smoke halogen-free flame retardant polyolefin, and the inner metal conductor (1) and the outer conductor (3) are separated by the polytetrafluoroethylene micropore compound insulation layer (2); the polytetrafluoroethylene micropore compound insulation layer (2) is made of modified polytetrafluoroethylene organic-inorganic nanocomposites filled with nano polyhedral oligomeric silsesquioxanes (POSS). According to the coaxial cable, the dielectric constant of the insulation layer of the cable is reduced. A traditional solid polytetrafluoroethylene insulation dielectric constant is reduced to 1.2-1.6 from 2.1 and is reduced by about 24 percent to 43 percent, and the signal attenuation of cable high-frequency communication is reduced.

The invention discloses a roadbed settlement monitoring device based on a fiber Bragg grating. The roadbed settlement monitoring device based on the fiber Bragg grating comprises at least two fiber Bragg grating liquid level sensors mounted on a monitoring surface; each fiber Bragg grating liquid level sensor comprises a cylindrical shell, and the bottom of each shell is mounted on a base; a rectangular cantilever beam, a cylindrical floating block and antifreezing solution are arranged inside each shell; the upper side and the lower side of each rectangular cantilever beam are respectively embedded into a fiber Bragg grating sensor, each floating block is suspended in the corresponding antifreezing solution, and each floating block is hinged with the free end of the corresponding rectangular cantilever beam; and the fiber Bragg grating sensors are welded and in serial connection with an optical cable, the optical cable is connected with a fiber Bragg grating demodulation instrument, strains of the rectangular cantilever beams when liquid levels in the shells are changed are acquired by virtue of the fiber Bragg grating demoulation instrument, adjacent upper sections of the shellsof the fiber Bragg grating liquid level sensors are communicated via a breather pipe, adjacent lower sections of the shells of the fiber Bragg grating liquid level sensors are communicated via a liquid flowing-through pipe, so as to enable the rectangular cantilever beams to produce bending deformation, and the liquid flowing-through pipe is connected with an automatic liquid level controller.

The embodiment of the invention provides an organic light-emitting display panel and a display device, relates to the technical field of display, and aims to effectively reduce the occupation of touchelectrode leads on the space of a frame area and facilitate the realization of a narrow frame. The organic light emitting display panel includes: a plurality of touch electrodes extending in a firstdirection and arranged in a second direction. The first leads correspond to the touch electrodes; the first lead is made of a transparent conductive material. The first leads and the touch electrodesare positioned on different layers. An insulating layer is arranged between the first leads and the film layer where the touch electrodes are located, in the direction perpendicular to the plane wherethe organic light-emitting display panel is located, the first leads and the corresponding touch electrodes are at least partially overlapped, and the first leads are electrically connected to the corresponding touch electrodes through via holes in the insulating layer. The plurality of first leads extend along the first direction and are arranged along the second direction.

The invention belongs to the technical field of high speed railway settlement monitoring, and discloses a high speed railway settlement monitoring system based on fiber bragg gratings. The high speedrailway settlement monitoring system is used for solving the problem that an existing high speed railway settlement monitoring system is low in accuracy. The high speed railway settlement monitoring system comprises at least two fiber bragg grating level gages installed on a monitoring face; and each fiber bragg grating level gage comprises a shell, wherein the bottom of the shell is installed ona base, an elastic convoluted diaphragm is installed in the shell, and the shell is divided by the elastic convoluted diaphragm into an upper liquid containing zone and a lower installing cavity, thelower end face of the elastic convoluted diaphragm is provided with two optical grating fixing columns, a pressure measuring optical grating is installed between the two optical grating fixing columns, a temperature measuring optical grating is further installed in the installing cavity, the temperature measuring optical grating and the pressure measuring optical grating are connected with a datacollecting system, and the data collecting system transmits collected data to a control center.

The invention relates to a multi-node electrical stimulation system and method. The system comprises a sending end and multiple electrical stimulation nodes worn on the parts, needing to be stimulated, of a human body. The sending end couples modulation electrical signals carrying node serial numbers and stimulation waveform parameters to human body communication channels through a sending electrode of the sending end according to the conduction characteristics of human body tissue. An integrated electrode of the electrical stimulation nodes is used for receiving the modulation electrical signals transmitted to the surface of the human body through the human body communication channels. The modulation electrical signals are processed through signal conditioning and demodulating, corresponding waveforms are selected through a microcontroller, corresponding electrical stimulation waveforms are output through the integrated electrode after boosting, and the corresponding parts of the human body are stimulated. The system is used for rehabilitation training of a patient with paralytic limbs caused by the reasons such as central nerve damage, the system carries out electrical stimulation on the corresponding parts of the limbs according to the transmission paths of electroneurographic signals when the limbs move, and therefore the rehabilitation of the moving function of the limbs of the patient is promoted.

The invention provides an antenna device with excellent penetrating performance. The antenna device includes a first radiator, a second radiator, a third radiator, and a dielectric substrate. The slotof the first radiator is configured to adjust the antenna impedance to achieve an effect of adjusting the resonance frequency. The dielectric substrate with a corresponding dielectric constant is arranged between the first radiator and the second radiator as required. The third radiator is used as a reflection plate, is located below the second radiator and increases the gain in the direction of0-degree angle. A low-dielectric-constant medium with a certain thickness is disposed directly above the first radiator. A feeding point is disposed on the first radiator. The second radiator is grounded. The antenna device has excellent penetrating performance, and can still smoothly transmit energy to the outside when buried in reinforced concrete.

To make an optical switch smaller, two frames are formed by etching in such manner that when they are stuck together to form a support member, an hexagonal opening appears. The end portions of a pair of fixed optical fibers are arranged in the bottom portions of a pair of opposing V-grooves provided in this hexagonal opening. A pair of movable optical fibers are fixed at the other end of the support member, and these movable optical fibers are arranged in such manner that their end faces are contiguous with the end faces of the pair of fixed optical fibers. A drive mechanism causes the end portions of this pair of vertically arranged movable optical fibers to move to the left or the right, come into contact with the walls of respective V-grooves, slide into the bottoms of the grooves, and thereby have their cores aligned with the cores of the fixed optical fibers. Alternatively, two parallel beams formed from silicon are formed on the inside of a single frame, a pair of mutually opposing projections are formed in approximately the middle portions of these beams, and the end portions of a pair of optical fibers are arranged in and in contact with V-grooves formed parallel to and on the opposing faces of this pair of projections.

The invention relates to an MOEMS vector hydrophone comprising a fiber (1), fiber collimators (2), a base (3), a silicon-based framework (4), a cantilever beam (5), and a micro cylinder (6). The cantilever beam (5) is erected at the center of the silicon-based framework (4) and is installed in the base (3). The fiber collimators (2) is installed in mounting holes (32) of the base (3); and the fiber collimators (2) and a corresponding platform (51) arranged on the cantilever beam (5) form an F-P cavity (16). The micro cylinder (6) is installed on the corresponding platform (51) at the cross-shaped intersection position of the cantilever beam (5). One end of the fiber (1) is connected with the fiber collimators (2) and the other end is connected to an external optical path demodulation device. According to the invention, acoustic-mechanical-optical conversion is carried out by the F-P cavity. With combination of the MEMS technology and the fiber sensing technology by the MOEMS technology, requirements of miniaturization, low power consumption, and electromagnetic interference prevention can be realized; and the front-side power-free state of the hydrophone as well as high-sensitivity high-resolution detection of a weak acoustic signal can be realized.

The present disclosure discloses an HDMI photoelectric composite cable. The HDMI photoelectric composite cable includes: a sheath, an optical fiber unit, a plurality of signal control wires, a ground wire and fillers. The optical fiber unit includes one or more optical fibers and an optical fiber sheath uniformly extruded on a periphery of the optical fibers. The signal control wire includes a metal wire and an insulating layer uniformly extruded on a periphery of the metal wire. The ground wire is a metal conductor. The fillers are arranged on peripheries of the optical fiber unit, the plurality of signal control wires and the ground wire. The optical fiber unit, the plurality of signal control wires, the ground wire, and the fillers arranged on the peripheries thereof are covered by the shielding layer, and the shielding layer is covered by the sheath.

The invention discloses a power line carrier centralized meter reading system node belonging automatic confirmation method. Through building a confirmation channel with frequency lower than 10khz, a main node at a low voltage side of a low voltage transformer can receive confirmation signals sent by slave nodes belonging to the main node through the confirmation channel and can not receive confirmation signals sent by nodes which do not belong to the low voltage side of the low voltage transformer of the main node through the confirmation channel, a node belonging abnormal condition can be avoided, automatic node belonging confirmation in the centralized meter reading system can be realized, and the cost for manual field inspection and test is reduced.

The invention discloses a fiber bragg grating pressure sensor capable of achieving positive and negative pressure monitoring and a testing method. The fiber bragg grating pressure sensor comprises a connector, a filter screen, a base, an outer shell, a corrugate pipe, a first fiber bragg grating, a second fiber bragg grating, an optical fiber, an optical cable connector, an armored optical cable, a brace, a flange plate, an outer shell cover and a strain beam, wherein the outer shell cover is used for protecting the optical fiber from a sealing glue sealing part to an optical cable connector part, and the strain beam is used for applying prestress. The fiber bragg grating pressure sensor capable of achieving the positive and negative pressure monitoring and the testing method are suitable for the monitoring of pressure safety of oil and gas pipelines, urban underground gas pipelines, heating power pipelines, water supplying pipelines, oil tank pipelines, oil conveying pipelines and other pipe networks, the potential safety hazards that an electronic sensor is electrified and is unsafe in nature are eliminated, and meanwhile the capacity of phases is also improved greatly; the fiber bragg grating pressure sensor is applied to the aspect of real-time online monitoring of coal and rock mass gas pressure, errors caused by single data monitoring are avoided, the sensitivity and the accuracy of the system are improved, manpower, material resources and time are saved, and meanwhile the danger probably brought by personnel on site can be avoided.

The invention discloses a multiple slot switch used for increasing the actual available slot number of the switch in a same cabinet and reducing high speed signal attenuation simultaneously. The multiple slot switch comprises a backboard, at least a main control board and two switch subunits. Each switch subunit comprises a plurality of interface cards, at least a first order switch board and at least a second order switch board. The main control board is connected with each interface card, the first order switch board and the second order switch board of the two switch subunits respectively and is used for managing the interface cards, the first order switch board and the second order switch board. To any switch subunit, any first order switch board in the switch subunit is in quadrature connection with any interface card and any second order switch board in the present switch subunit through a first socket connector which is fixed on the backboard. Between the switch subunits, each first order switch board of the switch subunit is connected with each second order switch board in the other switch subunit.