45results about How to "Short rise and fall times" patented technology

A DC high voltage power source is constituted by an AC-DC converting means (4, 6) that converts a voltage of a commercial AC power source (3) to a DC voltage and steps up the converted DC voltage, a DC-AC converting means (7) that converts the DC voltage stepped up by the previous means to an AC voltage, two insulating transformer (8, 9) that steps up the AC voltage converted by the previous converting means while insulating each others and a series connection of DC voltages obtained after converting the output voltages from the transformers to DCs and smoothing the same. The DC voltage of the DC high voltage power source is used as the power source to current amplifiers (19, 20, 21) constituted by a multi level PWM inverter circuit (18) of 3 levels and the currents flowing through X axis, Y axis and Z axis gradient magnetic field coil (15, 16, 17) in an MRI apparatus connected to these current amplifiers as loads are controlled by a switching control device (18q) so as to meet with current command values (22c1, 22c2, 22c3) from a sequencer 22 in the MRI apparatus. As a result, plural DC high voltage power sources necessary for the multi level PWM inverter is constituted by a comparatively simple circuit, in addition, while suppressing loss in the power sources, a small sized and highly accurate high voltage and large current power source device and a magnetic resonance imaging apparatus using the same are provided.

The invention relates to an electric lifting rod, which comprises a driving device and a lifting device, wherein the driving device comprises a driving motor, a reduction box and a hand-cranking box; the lifting device comprises a base, casing pipes and a transmission structure; and the casing pipes and the transmission structure are both connected to the base. The electric lifting rod is characterized in that the transmission structure is set into a rolling spiral transmission structure, and the transmission structure comprises lead screws and nuts cooperatively and fixedly connected with the lead screws. The relative displacement of the casing pipes of the electric lifting rod disclosed by the invention is lead screw and nut transmission, other transmission modes, such as steel wire ropes, are omitted, and the electric lifting rod has the advantages of big load bearing capability, high reliability and safety, simple transmission structure and convenience in disassembling and maintaining, and multi-section lead screws are in invaginating transmission.

Provided is an apparatus for conveying an electronic element, capable of ensuring the electronic element to be conveyed with high efficiency and without damage. The apparatus includes a first handover part containing the electronic element (12), a second handover part for moving and placing the electronic element (12), an adsorption picking/placing device (11) for absorbing the electronic element, a suction device (16), and a moving device (tilting stand (3), drive device (13)) for moving the adsorption picking/placing device (11) horizontally. The adsorption picking/placing device (11) is fixed on the moving device without movement up and down. The suction device (16) starts to attract when the adsorption picking/placing device (11) is arranged above the first handover part, and stops attracting when the adsorption picking/placing device (11) is arranged above the second handover part. Moving spaces (S1-S5) where the electronic element (12) and the adsorption picking/placing device (11) can be moved horizontally are formed between the first and the second handover parts.

The invention belongs to the field of laser devices, and particularly relates to an acousto-optic Q-switched ytterbium-doped all-fiber laser. In order to solve the problems of low coupling efficiency, high maladjustment sensitivity, complex experimental facilities and the like caused by separated component structure in Q-switched fiber laser, the invention adopts a technical proposal of the acousto-optic Q-switched ytterbium-doped all-fiber laser which comprises a fiber bragg grating (FBG), an acousto-optic modulator (AOM) with tail fiber, a multimode coupler, two pumping light-emitting diodes (LDs), ytterbium-doped double-clad fiber and output tail fiber, wherein the two pumping LDs couple pumping light to the ytterbium-doped double-clad fiber respectively by the multimode coupler; the ytterbium-doped double-clad fiber is connected between the output terminal of the multimode coupler and the output tail fiber; the FGB is connected to a signal terminal of the multimode coupler by the AOM with tail fiber, and forms a resonant cavity with the end surface of the output tail fiber simultaneously; and alternating voltage is applied on the AOM. The invention is mainly used in the manufacturing and designing of lasers.

The invention provides a loop circuit voltage control oscillator which comprises a time-delay unit in an even-number stage, wherein the same-phase input and the reverse-phase input of a common time-delay path in a time-delay unit in a first stage of the time-delay unit in an even-number stage are respectively connected with the same-phase input and the reverse-phase output of a time-delay unit in a previous stage of the time-delay unit of a first stage. The same-phase input and the reverse-phase output of the common time-delay path in a time-delay unit in every other stage are respectively connected with the reverse-phase output and the same-phase input of the time-delay unit in a pervious stage of the time-delay unit in every other stage. The input of a negative time-delay path of the time-delay unit in every stage of the time-delay unit in an even-number stage is connected with the output of time-delay units of the first two stages of the time-delay unit in every stage. The control-voltage input end and the power supply input end of the time-delay unit in every stage in the time-delay unit in an even-number stage are respectively connected with the input control voltage end of a loop circuit VCO and a DC power supply.

The invention provides a sensor support device which comprises at least one section of insulation operation handle, an insulation rod end, a sensor fixing end, a center penetrating screw rod, a rotation support rod, a rotation direction fixing screw rod and a sensor structure support, wherein one end of the insulation rod end is connected with the insulation operation handle; the sensor fixing end comprises a cylinder and a bottom surface, a notch is formed in the upper end of the cylinder, and the bottom surface is connected with the other end of the insulation rod end through a connection rod; the center penetrating screw rod is fixed with the outer side surface of the cylinder after radially penetrating through the cylinder; the center penetrating screw rod is sleeved with one end of the rotation support rod, a plurality of grooves are formed in the rotation support rod in the length direction, and the notch in the upper end of the cylinder enables the rotation support rod to rotate to the horizontal position around the center penetrating screw rod; the rotation direction fixing screw rod is connected to the cylinder opposite to the notch and matched with the grooves so as to fix the rotation support rod; the sensor structure support is fixed at the other end of the rotation support rod, and a sensor is fixed on the rotation support rod.

A display driver includes a data fetching unit that fetches first to Nth pixel data pieces corresponding to luminance levels of respective pixels and outputs the same at a timing of an edge of a clock signal, first to Nth amplifiers that amplify first to Nth gradation voltages corresponding to the first to Nth pixel data piece to obtain first to Nth driving voltages, and a bias voltage generation unit that generates and supplies bias voltages for setting current values of operation currents to the respective amplifiers. The bias voltage generation unit stores a first value and a second value of the bias voltage used for setting the current value to a higher value and a lower value, and generates a bias voltage having the first value during a period from the timing of the edge of the clock signal, and switches the voltage value to the second value thereafter.

The invention discloses a double speed-up mechanism for mechanical arm lifting. The double speed-up mechanism comprises a horizontal motion frame, a lifting fixing frame, a vertical motion frame A anda vertical motion frame B. The horizontal motion frame is movably mounted on a crossbeam, the lifting fixing frame is mounted on the horizontal motion frame, the vertical motion frame A is mounted onthe lifting fixing frame in a vertically movable manner, and the vertical motion frame B is mounted on the vertical motion frame A in a vertically movable manner. A servo motor drives a rack fixed tothe vertical motion frame A to drive the vertical motion frame A to move up and down, a synchronous pulley moves up and down along with the vertical motion frame A and rotates around an axle at the same time to drive a synchronous belt on the other side of the synchronous pulley to move up and down, and the synchronous belt moves up and down to drive the vertical motion frame B to move up and down. Therefore, under the driving action of the servo motor, the vertical motion frame A moves up and down and drives the vertical motion frame B to move up and down at a same speed, and the vertical motion frame A and the vertical motion B are identical in speed and stroke. The double speed-up mechanism has advantages that mechanical arm lifting time is shortened, connection cycle is met, and equipment cost is reduced.

The invention relates to the field of photoelectric detection, in particular to a gated silicon-based visible near-infrared single-photon detection device which comprises a direct-current high-voltage power supply, a radio-frequency transformer, a high-speed CMOS driver, an FPGA, a high-speed comparator, a human-computer interaction interface and a silicon-based visible near-infrared single-photon detector SAPD. The direct-current high-voltage power supply is connected in series with the inductor and the current-limiting resistor and then is connected with an N pole of the silicon-based visible near-infrared single-photon detector SAPD. The high-voltage gating pulse with short rising and falling time can be generated, the dark counting and post-pulse probability can be effectively reduced while the single-photon detection efficiency is improved, peak noise caused by the front edge and the rear edge of the gating pulse can be effectively filtered out, counting of avalanche signals is achieved, meanwhile, the width, the amplitude and the repetition frequency of the gating pulse can be adjusted, and working points can be conveniently adjusted for different silicon-based visible near-infrared single-photon detectors, so that the performance is better.

The invention provides a small trolley for conveying remains. The small trolley includes a framework; a transverse conveying mechanism which comprises a moving motor, a first driving chain wheel, a first chain, a first driven chain wheel, a moving shaft and a rolling wheel which are connected in sequence, the rolling wheel is driven to rotate under the action of the moving motor, and transverse conveying of the framework on the ground is achieved; and a longitudinal conveying mechanism which comprises a traction motor, a second driving chain wheel, a second chain, a second driven chain wheel, a transmission lead screw, a lead screw transmission traction mechanism, a lifting rack and a triangular inclined plate which are sequentially connected, wherein the inclined face of the triangular inclined plate is arranged upwards, and under the action of the traction motor, the lifting rack is driven to move along the inclined face of the triangular inclined plate, so that longitudinal conveying of the lifting rack on the frame is achieved. According to the small remains conveying trolley, operation is stable and reliable, the production cost is reduced, the cremation cost is reduced, the cremation efficiency is improved, and the civilized cremation custom is achieved.

The invention discloses a single handle tandem type hydraulic operation system of a sloping field hand tractor. The hydraulic operation system comprises an oil tank, an oil pump, a multiway valve, a first oil cylinder, a second oil cylinder, a first switch and a second switch, wherein the oil tank is connected with the oil pump; the oil pump is connected with the multiway valve; the multiway valve is connected with the first oil cylinder through the first switch, and is also connected with the second oil cylinder; the second oil cylinder is connected with the first oil cylinder through the second switch; and the multiway valve is directly connected with the oil tank. By using the structure, the lifting of the left and right wheels of the tractor can be finished through a single handle, the structure is simple and the operation is convenient.

A tomographic atom probe uses electrical pulses applied to an electrode in order to carry out evaporation of the sample being analyzed. In order to produce these electrical pulses, the tomographic atom probe comprises a high-voltage generator connected to an electrode by an electrical connection comprising a chip of semiconductor material. The probe also comprises a light source which can be controlled in order to generate light pulses which are applied to the semiconductor chip. Throughout the illumination, the chip is rendered conductive, which puts the high-voltage generator and the electrode in electrical contact so that a potential step is applied to the latter. The probe also comprises means for applying a voltage step of opposite amplitude to the previous step at the end of a time interval Δt₀, so that the electrode finally receives a voltage pulse of duration Δt₀.