92results about How to "Compressed Pulse Width" patented technology

The invention relates to the field of electronic products, in particular to an electronic cigarette and a temperature control method thereof. The electronic cigarette comprises an atomizer and a power supply unit and a control circuit electrically connected with the atomizer; a heating coil is accommodated in the atomizer and electrically driven by the power supply unit, and cigarette liquid is atomized after heating; the control circuit further comprises a controller, and a display circuit, a control signal acquisition circuit, a protective circuit, a resetting circuit, a charging circuit and a pulse width modulation circuit electrically connected with the controller; the pulse width modulation circuit modulates width of output pulse according to difference between real-time temperature of the heating coil and preset temperature, electronic smoke stable in taste is generated by controlling the temperature of the heating coil in real time, the problem of taste inconformity of the electronic cigarette due to instable temperature of the heating coil or too large temperature fluctuation is avoided, and meanwhile the problem of scorched flavor caused by over-high temperature of the heating coil is avoided.

The invention relates to an optical fiber failure positioning system and method. The optical fiber failure positioning method comprises the following steps of: sending out testing light at preset pulse width and pulse time interval to be transmitted in an optical fiber to be detected; detecting the power loss of the testing light; initially determining the failure position of the optical fiber according to the power loss of the testing light; determining a dynamic range of the testing light according to the power loss of the testing light; estimating a dynamic range of secondary testing light required when the optical fiber to be detected is monitored for the second time according to the initially determined failure position of the optical fiber; re-determining the pulse width and the pulse time interval according to the relationship among the dynamic range of the testing light, the pulse width and the pulse time interval; sending out secondary testing light at the re-determined pulse width and the pulse time interval to be transmitted in the optical fiber to be detected; detecting the power loss of the secondary testing light; and positioning the secondary failure for the optical fiber to be detected according to the power loss of the secondary testing light. By adopting the system and the method, the accuracy of optical fiber failure positioning can be improved.

A liquid crystal material for a display device includes a first chiral nematic liquid crystal component and a second component that exhibits no liquid crystalline phase at any temperature. The second component is present in an amount effective to reduce the bulk viscosity of the liquid crystal material by at least about 26 % at room temperature or is present in an amount of at least about 5 % by weight based upon the total weight of the liquid crystal material. The liquid crystal material may have a positive dielectric anisotropy. The second component may have a molecular weight not exceeding 205 grams/mole. Embodiments relate to a display device comprising the present material. Another aspect includes a method of increasing the switching speed in a display that employs the present material.

The invention discloses a high-power ultrashort-pulse optical frequency comb generation method based on a self-similar amplifier. The high-power ultrashort-pulse optical frequency comb generation method is based on self-similar amplification technology and effectively overcomes gain narrowing, bandwidth limitation and nonlinear phase distortion in pulse amplification. A light spectrum is effectively expanded, and the bandwidth of an output pulse is reduced. Furthermore the power of a mode-locked pulse is effectively expanded, thereby acquiring a high-power femtosecond pulse and improving carrier envelope phase zero-frequency locking precision. Furthermore carrier envelope phase zero-frequency locking technology based on an acoustic-optical crystal frequency shifter is utilized, thereby realizing large reaction bandwidth and high control precision, and realizing a high-frequency high-power ultrashort-pulse optical frequency comb through real-time control. The high-power ultrashort-pulse optical frequency comb generation method is advantageous in that the high-power ultrashort-pulse optical frequency comb generation method can be directly expanded and applied on femtosecond optical frequency comb control technology for obtaining the stable high-frequency high-power ultrashort-pulse optical frequency comb.

The invention discloses a frequency doubling self-regulating Q green laser inside a double-doped chrome yttrium aluminum garnet composite photassium titanyl phosphate cavity,and relates to a green laser. The self-regulating Q green laser is provided with a pumping source, a micro lens, a first column-shaped lens, a second column-shaped lens and a laser working medium Cr, Nd:YAG/KTP composite crystal. The pumping source, a micro lens, the first column-shaped lens, the second column-shaped lens and the laser working medium Cr, Nd:YAG/KTP composite crystal sequentially are arrayed on a same plain shaft from front to back. Anti-reflection film and a high-reflective film are plated on the rear surface of the laser working medium Cr, Nd:YAG/KTP composite crystal to serve as a back cavity lens of the laser cavity. High-reflective film and anti-reflection film are plated on the front surface of the laser working medium Cr, Nd:YAG/KTP composite crystal of the laser cavity. The number of optical elements used for the laser is small, the production cost is low, the structure is simple and compact, and the laser is convenient to produce and assemble and operate and use by a non-professional person.

The invention discloses a processing method and device of a transparent material, and provides an optical fiber laser of which the wave length is 1020 nm to 1090 nm. The processing method is characterized in that laser beams output by a seed laser are subjected to energy amplification through an optical fiber amplifier, laser pulse trains are output, each pulse train comprises at least two laser pulses, pulse width is smaller than 200 ps, peak power of the pulses is larger than 100 kW, the time among the laser pulses in each pulse train is smaller than 90 ns, the interval among the pulse trains is larger than 240 ns, and the total pulse number in each second is larger than 50,000, wherein ultrafast laser beams output by the laser are subjected to energy amplification only through the optical fiber amplifier; and the laser is focused on a to-be-processed position of the transparent material, a focus position is moved, processing is carried out according to a set track, a focus point isgradually risen, and the transparent material is processed from bottom to up. According to the processing method, material removal efficiency can be greatly improved, a heating or etching follow-up procedure is not required, and bevel angles are avoided.

The invention discloses an ultrafast ultraviolet laser processing method and device of a transparent material, and provides an optical fiber laser of which the wave length is 1020 nm to 1090 nm. The processing method is characterized in that energy amplification is carried out through an optical fiber amplifier; optical third harmonic generation is carried out, and ultraviolet laser pulse trains are acquired; each pulse train comprises at least two laser pulses, pulse width is smaller than 200 ps, peak power of the pulses is larger than 50 kW, the time between the adjacent laser pulses in thepulse trains is smaller than 90 ns, the interval among the pulse trains is larger than 240 ns, and the total pulse number in each second is larger than 50000; ultrafast laser beams output by the laserare subjected to energy amplification only through the optical fiber amplifier; and the ultraviolet laser beams are focused on the lower surface of the to-be-processed transparent material, processing is carried out according to a set track, a focus point is gradually risen, and the transparent material is processed from bottom to up. According to the processing method, material removal efficiency can be greatly improved, a heating or etching follow-up procedure is not required, and bevel angles are avoided.

The invention discloses a processing method and device for an ultrafast green laser transparent material and provides an optical fiber laser, the wave length of which is ranged between 1020 nm and 1090 nm. By adopting the optical fiber laser for amplifying energy, the processing method is characterized by comprising the following steps: then carrying out optical frequency doubling to obtain a green laser pulse string, wherein each pulse string comprises at least two laser pulses, the pulse width is smaller than 200ps, the peak power of the pulse is greater than 100 kW, the time of adjacent laser pulses in the pulse string is shorter than 90 ns, the interval time among the pulse strings is greater than 240 ns, and the total pulse number per second is greater than 50,000; carrying out energyamplification on the ultrafast laser string output by the laser only with the optical amplifier; and focusing the green laser string to the lower surface of a to-be-processed transparent material, and processing the material according to a set track and raising the focus point gradually so as to process the transparent material from bottom to top. According to the processing method, the removal efficiency of the material can be improved greatly without a follow-up step of heating or acid invasion and generation of an oblique angle.

The invention discloses a welding machine arc striking control circuit. The welding machine arc striking control circuit comprises a pulse witch sampling circuit, an error comparison amplifier circuit, a pulse width setting circuit and a pulse width recovery circuit; the pulse witch sampling circuit is used for obtaining pulse driving signals from an inverter driving circuit which is arranged in a welding machine to generate pulse width sampling signals; the pulse width setting circuit is used for generating pulse width setting signals; the error comparison amplifier circuit is used for enabling the pulse width sampling signals to be in comparison with the pulse width setting signals and lowering the pulse width control voltage in the welding machine after error signals which are obtained through comparison are amplified; the pulse width recovery circuit is used for enabling the pulse width control voltage to be recovered to the preset working voltage after the arc striking of the welding machine succeeds. According to the welding machine arc striking control circuit, the pulse width of the pulse driving signals during the arc striking of the welding machine is reduced and accordingly the impact current in the process of the arc striking of the welding machine can be significantly reduced, the impact on related devices which are arranged in the welding machine during arcing of the welding machine is reduced, the reliability of the integral machine is improved, and the service life of the integral machine is extended.

The invention discloses a solar silicon cell nanosecond-pulse green laser scriber. The solar silicon cell nanosecond-pulse green laser scriber comprises a laser component, a two-dimensional electro-migration platform (1), a water cooling component (13), a laser power supply (14) and a complete machine control component (15), wherein the two-dimensional electro-migration plateform (1) is arranged on the light path (3) of the laser component; the laser component comprises an all-trans cavity plate, a Q-regulator, a laser bar (9) and an output cavity plate; particularly, the output cavity plate is a Gauss mirror (6), and the all-trans cavity plate is a concave mirror (11) which is complementary with the Gauss mirror (6); the light path (3) between the Gauss mirror (6) and the two-dimensional electro-migration platform (1) is provided with a double-frequency crystal (5) the non-transmission surface of which is provided with a semiconductor cooler; and the Q-regulator is an electro-optical Q-regulator (10) consisting of a polarizer (101), a first Q-regulation crystal (102), a second Q-regulation crystal (103) and a 1/4 wave plate (104) which are connected in series. The width of the scribed seam is 50 mu m, and the precision is 10 mu m. The invention increases the scribing speed and depth by 50%, enhances the scribing efficiency and lowers the production cost.

The invention relates to a narrow pulse driving system and method for a pulse laser. A digital output port of a micro-control unit is connected with a digital input port of a digital-to-analog converter, the clock output port of the micro-control unit is connected with a clock input port of a D trigger, the zero clearing end of the D trigger is connected with a capacitor 1 and an adjustable resistor 1, and the output end of the D trigger is connected with the adjustable resistor 1 and the enabling end of an analog switch, the analog output end of the digital-to-analog converter is connected with the positive input end of an operational amplifier, the output end of the operational amplifier is connected with the analog input end of the analog switch, the output end of the analog switch is connected with an input end of an analog buffer, the output end of the analog buffer is connected with the grid electrode of an MOS tube, the source electrode of the MOS tube is connected with a sampling resistor 2, the drain electrode of the MOS tube is connected with the negative pole of a laser diode, the positive pole of the laser diode is connected with a power supply, the sampling resistor 2is in signal connection with the input end of a smooth filter, the output end of the smooth filter is connected with the analog input port of an analog-to-digital converter, and the digital output port of the analog-to-digital converter is connected with the digital input port of the micro-control unit. The regulation is simple, and the stability of laser pulse generated by driving is good.

The invention relates to the field of electric pulse generation, biomedicine and food processing, and provides a composite high voltage pulse electric field, and an electric field sterilization device and method in view of the problems in the prior art. A microsecond high voltage pulse generation circuit and a nanosecond high voltage pulse generation circuit are triggered by a trigger control circuit that integrates electric parameter detection with waveform parameter control, in order to output microsecond and nanosecond high voltage pulse signals according to a set pulse waveform parameter and a time sequence, the microsecond and nanosecond high voltage pulse signals are loaded to a sterilization processor together, the composite high voltage pulse electric field with a preset waveform structure is loaded on the sterilization processor to load a microsecond-nanosecond composite high voltage pulse electric field on a processed material so as to form dual inhibition of survival ability and fertility of bacteria, thereby improving the sterilization efficiency of the pulse electric field, and prolonging the expiration date of the processed material.

The invention discloses a steel rail flaw detection ultrasonic waveguide inclined probe and a flaw detection method thereof. The probe comprises a shell, a sound absorption filler, at least one dielectric unit and at least one interface, wherein each dielectric unit is arranged inside the shell and comprises a wedged block, a dielectric wafer, a cable wire and a damping block; the dielectric waferis a dielectric ceramic piece of a thickness vibration mode; an included angle is formed between one surface of the wedged block and the horizontal plane; one surface perpendicular to a vibration direction, of the dielectric wafer, is flatly adhered to the surface of the wedged block; the damping block is tightly adhered to another surface perpendicular to the vibration direction, of the dielectric wafer; the sound absorption filler is arranged inside a vacant space except the dielectric unit inside the shell; the interface is arranged on one surface of the shell and is connected with the dielectric wafer through the cable wire. Due to adoption of the dielectric wafer of the thickness vibration mode, the probe is high in signal to noise ratio, low in cost and convenient to popularize, inaddition can be applied to flaw detection on rail heads and rail bottoms, and is long in single detection distance.

The invention discloses a high-energy hundreds of picoseconds laser device based on stimulated Brillouin scattering pulse compression, and belongs to the field of optical instruments, so as to solve the problem that the prior laser can not realize narrow pulse high energy single longitudinal mode output. According to the scheme of the invention, after p polarized light generated by an oscillator passes through a beam expanding telescope, the light transmits a light isolation system, the transmitted p polarized light is amplified and changes into s polarized light via a 90-DEG rotor, the s polarized light is further amplified and then converted into circular polarized light via a 1/4 wave plate, continuous reflection via two plane mirrors is sequentially carried out, a direction is changed, the light then enters a stimulated Brillouin scattering generation unit, and stimulated Brillouin scattering is generated. Generated back Stokes light is returned along the original path, continuous reflection via two plane mirrors is sequentially carried out, a direction is changed, the light is converted into p polarized light via a 1/4 wave plate, the p polarized light is amplified and then converted into s polarized light via a 90-DEG rotor, and the s polarized light is further amplified and separated by a second polarized film and reflected out of the light path.

The invention discloses an all-fiber Q-switched fiber laser based on stimulated Brillouin scattering, which comprises a low-reflectivity fiber Bragg grating, a laser beam combiner, ytterbium-doped doubly-clad active optical fibers, Sm3+-doped single-mode optical fibers, a high-reflectively fiber Bragg grating and a plurality of pumping sources. The core diameter of the Sm3+-doped single-mode optical fibers is smaller than the core diameter of the ytterbium-doped doubly-clad active optical fibers. The laser beam combiner is provided with a first beam combining connecting end, a second beam combining connecting end and a pumping input end. The first beam combining connecting end is connected with the low-reflectivity fiber Bragg grating. The pumping input end is respectively connected with the input ends of the plurality of pumping sources. The second beam combining connecting end is connected with one end of the ytterbium-doped doubly-clad active optical fibers. The other end of the ytterbium-doped doubly-clad active optical fibers is fused with one end of the Sm3+-doped single-mode optical fibers. The other end of the Sm3+-doped single-mode optical fibers is connected with the high-reflectively fiber Bragg grating. The all-fiber Q-switched fiber laser based on stimulated Brillouin scattering has a passive Q switching function, the automatic Q switching stability is good, the pulse peak power is improved and the pulse width is reduced.

This invention relates to super short impulse time and space purifying device, which comprises one quarter wave sheet, focus lens, second quarter wave sheet and bias tester and is characterized by the following: a, the said first and second quarter wave sheets are as zero quarter wave sheet with rapid axis direction crossed; b, there are located with non-linear positive transparent solid material and silver concaved reflection lens between the said focus lens and second quarter wave sheet; c, the said silver coated concaved reflection lens and the said focus lens are at same height with distance of two focus as co-focus point.

The invention relates to a current-limiting protection and short-circuit protection circuit with a self-recovery function. The circuit comprises a current detection circuit, a rectifying circuit, a current pulse amplitude control circuit, a current peak shielding circuit, a comparison circuit, a level displacement filter circuit and a switch circuit. According to the circuit, current-limiting protection and short-circuit protection functions of a switch power supply can be achieved with only one comparator, one reference voltage, one N-type short-circuit switch and a few of passive elements, and accordingly the circuit is simple. On the premise that performance of the circuit is not reduced, compared with the occupied area of a conventional short-circuit protection circuit, the occupied area of the circuit is reduced by 60%. The circuit can be widely used for high-reliability switch power supply circuits in the field of spaceflight and aviation.

The invention provides a Yb: LYSO laser for Kerr lens mode self-locking. The Yb: LYSO laser is used for outputting lasers with a mode being locked. The Yb: LYSO laser comprises a pumping source, a laser crystal and an optical system, wherein the pumping source is used for providing pumped lasers, the laser crystal is made of a Yb: LYSO material and is used as a gain medium and a Kerr medium, the optical system is composed of a plurality of optical elements, and the optical system can work with the pumping source and the laser crystal according to a Kerr lens mode locking mechanism. The optical system comprises a resonance cavity used for forming a roundtrip optical path for the lasers, and the laser crystal is arranged on the roundtrip optical path. The resonance cavity is provided with a first end mirror which is arranged at the first end of the roundtrip optical path and used for reflecting the lasers. The first end mirror is a semiconductor saturable absorption mirror and is used for starting and stabilizing Kerr lens mode locking. According to the Yb: LYSO laser for Kerr lens mode self-locking, the semiconductor saturable absorption mirror is used for assisting in mode locking, Kerr lens self-starting mode locking is achieved on the Yb: LYSO laser crystal, the Yb: LYSO laser can stably operate for a long time, and 61fs femtosecond pulse output is achieved.

The invention discloses a piezoelectric ultrasonic wave guide probe for steel rail bottom flaw detection and a flaw detection method thereof. The probe comprises an outer layer casing, a plurality ofpiezoelectric units and at least one interface, wherein each piezoelectric unit comprises a piezoelectric wafer, a cable wire, a damping block, a sound absorption filling material, an elastic elementand an inner layer casing; the piezoelectric wafer is a piezoelectric ceramic piece with the length direction vibration mode and is arranged at the bottom of the outer layer casing; the vibration direction is parallel to the horizontal surface; one side, parallel to the vibration direction and near the inside, of the piezoelectric wafer is tightly attached to the damping block; the damping block is arranged in the inner layer casing; the sound absorption filling material is filled between the damping block and the inner layer casing; the elastic element is arranged between the inner layer casing and the outer layer casing; the connector is arranged on the top of the outer layer casing and is connected with the piezoelectric wafer through the cable wire. The piezoelectric wafer with the length direction vibration mode is used; the sensitivity is high; the single-time detection distance is long; the signal-to-noise ratio is high; the small damage can be inspected out; meanwhile, the costis low; the popularization is convenient.

The invention provides an anti-interference ultrasonic probe. The anti-interference ultrasonic probe comprises a shell, a wedge block, a piezoelectric wafer and a probe interface, wherein the piezoelectric wafer is connected with the probe interface by a circuit; the wedge block is arranged in the shell and is provided with an end surface, a wedge-shaped surface and a connecting surface connected between the end surface and the wedge-shaped surface; the end surface is provided with a groove; the connecting end of the probe interface and the piezoelectric wafer is arranged in the groove; one end of the probe interface, which is opposite to the piezoelectric wafer, extends out of the shell; the connecting surface is provided with stripy bulges with round and flawed sections; and the planes of the bulges are coincided with the connecting surface. The anti-interference ultrasonic probe provided by the invention has the advantages that the connecting surface of the wedge block is provided with the stripy bulges, and a plurality of surfaces can be utilized for carrying out multi-time reflection and refraction on redundant ultrasonic waves reflected, so that clutter absorption is realized; in addition, the side of the probe interface is provided with absorbing blocks which can suppress the needless vibration of the piezoelectric wafer, so that the pulse width is reduced, the resolution ratio is improved and further the accuracy of measurement is improved.