38results about How to "Avoid introducing errors" patented technology

The invention discloses a brushless doubly-fed motor control system, a feed forward control method and a parameter identification method. The control system comprises a d-axis control structure for outputting a d-axis component of a voltage command value and a q-axis control structure for outputting a q-axis component of the voltage command value. The d-axis control structure comprises a first PIcontroller, a first proportional controller, a second proportional controller, a first differential controller, a first superimposer and a second superimposer. The first proportional controller, the second proportional controller and the first differential controller are used for generating a first d-axis intermediate component, a second d-axis intermediate component and a third d-axis intermediate component respectively. The first PI controller is used for outputting a d-axis component of a voltage initial reference value; and the second superimposer is used for carrying out superposition processing on the d-axis feed forward quantity of the voltage reference value and the d-axis component of the voltage initial reference value to output a voltage command value. The control system eliminates a coupling term between the current and voltage of a control winding, and realizes accurate closed-loop control.

The invention belongs to the technical field of induction current detection, and specifically relates to a non-contact induction current detection system and method based on phase-locked amplification, including a control circuit, a wave-to-wave converter, a double-ridge waveguide, a power module, and a first radio frequency signal source , a lock-in amplifier, a second radio frequency signal source, two ends of the double ridge waveguide are respectively connected with a wave-to-wave converter, and the double-ridge waveguide is respectively connected to a control circuit, a power module, a first radio frequency signal source, A lock-in amplifier, the lock-in amplifier is connected with a second radio frequency signal source, a sensitive unit bridge wire and a tunnel magneto-resistance probe are arranged in the double ridge waveguide, and the sensitive unit bridge wire is connected with the tunnel magneto-resistance probe. The invention can effectively avoid the error introduced by the test equipment, and can extract the effective output voltage value of the tunnel reluctance probe in the interference environment through the phase locking method, thereby indirectly obtaining the magnitude of the induced current on the bridge wire of the sensitive unit. The invention is used for the detection of induced current.

The invention relates to the technical fields of image processing and projection focusing, and specifically discloses a focusing method, a focusing device and a readable storage medium for an ultra-short-focus projector. The present application projects the projection image to the projection surface; drives the focus motor to rotate a stroke in a stepwise manner, and obtains the first projection screen image and the second projection screen image at each step position of the focus motor; obtains the corresponding image of the first image acquisition device The position of the first focus motor, and the position of the second focus motor corresponding to the second image acquisition device; determine the focus position according to the position of the first focus motor and the position of the second focus motor; drive the focus motor to reach The focus position, the method to complete the focus. By analyzing the sharpness of the images of the projected screen areas on both sides to determine the optimal focus position on both sides, and then comprehensively determine the final focus position, the computational complexity is greatly reduced, and at the same time, the introduction of sharpness data in the original image due to the error of the splicing method can be avoided. error problem.

The invention discloses a ratio method for correcting topographic influence in electromagnetic prospecting. The ratio method comprises the steps of acquiring a surface layer resistivity value without topographic influence to serve as a standard resistivity of topographic correction; drawing an in-line topographic profile, respectively comparing the topographic profile with a frequency point profile of a frequency domain electromagnetic method and a time channel profile of a time domain electromagnetic method, and judging the topographic influence suffered by the actually measured data according to the influence rule of the topography on the resistivity in the frequency domain and the time domain electromagnetic field; observing from the highest frequency point of the frequency domain electromagnetic method and the earliest time channel of the time domain electromagnetic method so as to obtain the topographic response which is closest to the surface layer until the absence of low-frequency frequency point of the topographic influence is observed in the frequency domain electromagnetic method and the absence of the late time channel of the topographic influence is observed in the time domain electromagnetic method, and acquiring the observation data without topographic influence; and performing topographic correction according to a ratio formula of pcorrected(i,j)=pmeasured(i,j) [pstandard(i) / pmeasured(i,l)]C(i,j). The ratio method is good in correction effect in the process of correcting the topographic influence, is high in feasibility and can be widely applied to topographic influence correction in electromagnetic prospecting.

The invention discloses a sample preparation instrument which comprises an outer shell; a nitrogen blow tank is formed in the top in the shell; the lower part of the nitrogen blow tank is provided with a nitrogen blow plate device; slide ways are respectively arranged at the two sides of the nitrogen blow plate device and in the middle of the nitrogen blow plate device; the nitrogen blow plate device is also provided with nitrogen blow plates capable of sliding along the slide ways; each slide way is provided with a blocking groove, and each nitrogen blow plate is fixed by the corresponding blocking groove; a first fixing groove used for placing a sample liquid receiving plate is formed in the bottom in the outer shell; the first fixing groove is sequentially provided with an intermediate sealing ring and a second fixing groove; the second fixing groove is provided with a sample preparation plate and a solid phase extraction (SPE) bracket; a lever, an oscillator and a negative pressure pump are arranged at the lower part of the first fixing groove; the side surface of the first fixing groove is provided with two small holes which are respectively connected with two fans, and a gas heating device located at the back of the first fixing groove; and the back of the outer shell is provided with a waste liquid outlet hole, an outer nitrogen interface, a negative pressure interface, a power interface and a nitrogen heating device.

The invention discloses a computational imaging-based optical lens numerical aperture measurement method. The method includes the following steps that: a microscopic optical path system for numericalaperture measurement is constructed; the relative positions of a photographed object and a camera in the microscopic optical path system are adjusted, so that a microscopic image with a high dynamic range is obtained; a system magnification factor is calculated on the basis of to the size of the pixels of the camera and according to the size of the photographed object in the image; digital image processing is performed on the obtained image, so that a frequency diagram with a circular contour is obtained, and image processing is performed, so that the diameter of the circle is calculated; andthe numerical aperture of the lens is calculated according to the diameter of the circle and on the basis of the size of the pixels of a light sensing component, the system magnification factor, and an illumination light center wavelength. With the method of the invention adopted, the numerical aperture of any lens in life can be measured. The method has the advantages of simple operation processand high measurement precision. According to the method, the numerical aperture is obtained through calculation, human observation is rarely required, and the introduction of additional error can be effectively avoided.

The present invention is entitled "Self-Contained Biological Indicators". Disclosed herein is a biological sterilization indicator that, in some embodiments, includes a housing having a first housing and a second housing, an ampoule containing a liquid growth medium, and at least partially An insert disposed in the first housing. A portion of the ampoule may be disposed within the interior of the first housing. The insert may have a platform comprising a top surface, a docking surface and side surfaces, a first void disposed in the platform and a second void configured to allow a first volume of liquid growth medium to enter the second void. In the housing, a second void is disposed through at least a portion of the side surface and is configured to allow a second volume of liquid growth medium to enter the second housing. The second void of the insert may be an angled cut through the abutment surface and the side surface, the angled cut may be disposed completely below the top surface. In some embodiments, stress concentrators and other features are included to reduce the force required to activate the biological sterilization indicator.