Abstract: A nuclide identification method, a system and an electronic device are provided, which relates to the field of nuclide identification. According to statistical characteristics, a background probability density function and a Compton probability density function in a ROI are determined. An energy Bayesian factor and a time Bayesian factor are determined based on energy and time interval information in a sequence of the nuclear detection events obtained by measurement. By combining the two factors, Compton plateau can be effectively identified and distinguished.

Abstract: A bidirectional reflectance distribution function (BRDF) measurement system and method, an electronic device, and a storage medium. The BRDF measurement system includes: a blackbody, a spectroradiometer and a controller; where in case that the blackbody is heated to a target temperature, it undergoes a solid-liquid phase change; the spectroradiometer is used to measure the blackbody and transmit a first measurement signal to the controller, and in case that the blackbody irradiates a to-be-measured point on a sample surface, the spectroradiometer is further used to measure radiation from the to-be-measured point, and transmit a second measurement signal to the controller; and the controller is used to obtain a BRDF of the to-be-measured point based on the first measurement signal, the second measurement signal, the target geometric relationship, a target mapping relationship and a dimension parameter of the blackbody.

Abstract: The present application relates to a nano-liter photoionization mass spectrometry ion source device and an operation method thereof. The nano-liter photoionization mass spectrometry ion source device includes a nano-tip, configured to load a sample solution, thus achieving a nano-electrospray process; a metal electrode, inserted into the nano-tip to contact with the sample solution directly, thus providing a high-voltage electric field for the nano-electrospray; and a UV lamp, configured to emit a high-energy ultraviolet photon to be combined with a gaseous molecule obtained by vaporizing the sample solution, thus achieving a photoionization process. Directed to the problems such as low ionization efficiency, poor sensitivity and more impurity interference existing in the unicellular mass spectrometry process of trace low-polar compounds in small-volume samples, a nano-liter photoionization mass spectrometry ion source device suitable for the analysis on low-polar compounds in small volume, e.g.

Abstract: A composite measurement system for measuring nanometer displacement is provided. The system includes: a light source, a polarization beam splitting prism, a first phase change module, a second phase change module, a first right-angle prism, a second right-angle prism, a non-polarization beam splitting prism, a scalar interference light collection module, a vector interference light collection module and a displacement calculation module. In the present disclosure, a photodetector is configured to collect an intensity of scalar interference light of the object to be measured being moved, to obtain a periodic light intensity change curve; a CCD camera is configured to collect images of interference vortex light of the object being moved; and the displacement calculation unit is configured to calculate a displacement of the object according to integer periods of the light intensity change curve and angles of image changes of the interference vortex light.

Abstract: The present disclosure provides an artificial cell for single-cell mass spectrometry (SCMS) measurement and a preparation method thereof. In the present disclosure, the artificial cell includes an internal aqueous phase, an intermediate oil phase, and an external aqueous phase; where the internal aqueous phase includes polyethylene glycol (PEG) and a polyvinyl alcohol (PVA) aqueous solution, and the intermediate oil phase includes a chloroform-hexane mixture of L-?-phosphatidylcholine; and the external aqueous phase includes PVA and an F-68 aqueous solution. Compared with natural cell samples, new artificial single cells based on microfluidic self-assembly provided by the present disclosure have better uniformity, stability, and controllability. The artificial cell can effectively avoid significant measurement differences between individual single-cell samples, and effectively solve the problem of difficulty in stably preserving biological samples.

Abstract: Disclosed are a device and a method for measuring laser displacement. The device comprises an interferometric measurement module, a laser light source module, a signal modulation module, a control processing module and an optical vernier demodulation module. The control processing module controls the signal modulation module to apply a light source modulation signal to the laser light source module, so that the laser light source module provides two laser beams with fixed frequency difference to the interferometric measurement module. The control processing module controls the interferometric measurement module to perform interferometric measurement. During measurement, lasers respectively interfere in two Fabry-Perot cavities in the interferometric measurement module, and are detected by two photodetectors to form main and secondary measurement interference signals.

Abstract: The invention discloses a four-quadrant interferometry system based on an integrated array wave plate. PBS splits an output laser light into two paths, the reflected light and the transmitted light are respectively transformed into reference light and measuring light, the reference light and the measuring light are converged in PBS, the converging light enters a signal receiving unit and is split into four beams, and the four beams irradiate on a four-quadrant interference signal detector with an integrated array wave plate. The invention solves the problems that the existing signal detection system occupies a large space, is not conducive to array integration, and cannot be used in scenes with high space and size requirements.

Abstract: The present invention discloses a trusted alliance block chain digital calibration certificate system and an operation method therefor. The system comprises: a distributed ledger system (10) of a distributed storage system based on a hyperledger fabric; a CA system (11) for management of all entity identity certificates and registration of identities in the system; a UTC time calibration server (12) for providing a UTC time calibration service for all block chain node servers of the system; and a digital calibration certificate subsystem (13) for generating, by means of alliance management, instrument organization management, and calibration institution management, a digital calibration certificate from calibration certificate data by a digital signature technology, extracting related entity information, and forming original information of multiple data blocks.

Abstract: The present disclosure provides a system and method for verifying alternating current (AC)/direct current (DC) conversion of an ultralow-frequency voltage. The system includes a quantum voltage generation system, a low-frequency signal source, a follower, three switches, a double-heater-strip thermoelectric converter, a nanovoltmeter, a clock source, a high-precision digital sampling system, and an upper computer. Based on DC and AC quantum voltage technologies and with reference to the double-heater-strip thermoelectric converter, an ultralow-frequency voltage is traced to a DC quantum voltage through AC/DC conversion, and a conversion result is compared with an AC quantum voltage to verify rationality of precision and an uncertainty evaluation result of AC/DC conversion of the ultralow-frequency voltage, so as to ensure reliability of AC/DC conversion of the ultralow-frequency voltage. This resolves a problem that the AC/DC conversion result of the ultralow-frequency voltage cannot be verified.

Abstract: A monocular vision-based method for measuring displacement and trajectory of planar motion. In this method, a sequence image of a motion of a high-contrast feature mark fixed on a moving plane to be measured is collected using a camera. A sub-pixel coordinate of a feature edge of a linear motion of the sequence in an X direction and a Y direction is extracted using a sub-pixel edge detection method, and the sub-pixel coordinate is converted into a corresponding world coordinate. The world coordinate of the feature edge is fitted based on a least squares principle to obtain a straight line of the feature edge to realize decoupling measurement of a displacement in the X direction and the Y direction. The planar motion trajectory is obtained through measuring the displacement in the X direction and the Y direction.

Abstract: The present application provides a trusted space positioning calibration service system and an operation method thereof. The system includes: a differential benchmark data service module, a positioning data digital calibration server and a trusted space positioning calibration apparatus.

Abstract: A method for achieving terminal-pair definition of four-terminal-pair (4TP) impedance and an application thereof are provided, which belongs to the field of precision measurement and metrology. A current output terminal of a two-stage follower is connected to a high current terminal of impedance through a coaxial line, and a voltage output terminal of the two-stage follower is connected to a high voltage terminal of the impedance through the coaxial line, which makes current of the high voltage terminal be 0, and core wire currents and outer wire currents of the high current terminal equal and reverse. The terminal-pair definition of the 4TP impedance can be satisfied; and the follower is added to make a bridge ratio variable and isolate effects of bridge load changes, thereby accelerating a balancing speed of the 4TP impedance bridge, and achieving accurate and fast comparative measurement having high precision of the 4TP AC impedance.

Abstract: A method for measuring angular velocity and angular acceleration based on monocular vision. Firstly, a movement sequence image of a feature mark fixed on a working table of a rotary motion generating device is acquired via an acquisition and imaging device. Secondly, a region of interest on the movement sequence image of the feature mark under different shooting distances and rotating conditions is determined by cyclic matching between a set of circular templates and the movement sequence image of the feature mark. Then, a sub-pixel of feature line edges in the region of interest is extracted using a line segment detection method, and only the feature line edges in a motion direction are retained through a constraint of the number of edge points. Finally, the angular velocity and angular acceleration are calculated by using the extracted feature line edges in the motion direction.

Abstract: A six-degree-of-freedom measurement method by machine vision based on physical decoupling. A point projector capable of emitting three laser beams perpendicular to each other is placed on a measured object. A rear-projection screen is configured to allow the three laser beams to be projected thereon as three laser points. The collection of motion images is performed by a camera. Plane coordinates of the three laser points are obtained by processing a sequence image. A mathematical decoupling model is built according to a nature of sphere and a spatial position relationship of three laser beams. The plane coordinates of the three laser points are input into the mathematical decoupling model to obtain six-degree-of-freedom information of the measured object.

Abstract: A method for calibrating linear vibration and angular vibration based on monocular vision. A motion sequence image of a feature mark is acquired by an industrial camera, and an output signal of a linear and angular accelerometer is acquired by a data acquisition card, where the feature mark and the linear and angular accelerometer are fixed on a work table. An exciting acceleration of the linear and angular accelerometer is measured by a monocular vision method integrating a camera calibration method and a sub-pixel edge extraction method based on line segment detection. The exciting acceleration and the output signal are fitted by a sine approximation method, respectively, and corresponding fitted peaks are obtained. A sensitivity of the linear and angular accelerometer is obtained according to the fitted peaks.

Abstract: A surface texture probe and a surface texture measurement apparatus with a vibrational membrane are provided. The probe includes a housing and a vibrational membrane, a stylus holder, a vertical guide assembly, a guide adjustment assembly and a stylus. An inner end of the vibrational membrane is attached to an upper end of the stylus holder. An outer end of the vibrational membrane is fixed to a vibrational membrane connection assembly fixedly connected to the housing. The vertical guide assembly is fixed inside the housing and slidably connected to the stylus holder and configured to guide the stylus holder to move in a vertical direction. The stylus is fixed to a lower end of the stylus holder. The guide adjustment assembly is mounted on the vertical guide assembly and configured to adjust a sliding friction force between the vertical guide assembly and the stylus holder.

Abstract: Disclosed are a device and a method for measuring laser displacement. The device comprises an interferometric measurement module, a laser light source module, a signal modulation module, a control processing module and an optical vernier demodulation module. The control processing module controls the signal modulation module to apply a light source modulation signal to the laser light source module, so that the laser light source module provides two laser beams with fixed frequency difference to the interferometric measurement module. The control processing module controls the interferometric measurement module to perform interferometric measurement. During measurement, lasers respectively interfere in two Fabry-Perot cavities in the interferometric measurement module, and are detected by two photodetectors to form main and secondary measurement interference signals.

Abstract: The present disclosure provides a scanning probe, a method and an apparatus for manufacturing the scanning probe. The scanning probe includes a base and a micro-tip disposed on an end of the base, wherein at least a section of the micro-tip comprises a lateral surface with a concavely curved generatrix. In the method, an end of a probe precursor is immersed in a corrosive solution by having a length direction of the probe precursor inclined with a liquid surface of the corrosive solution. The probe precursor is corroded by the corrosive solution while a corrosion current of the corroding is monitored. The probe precursor is moved away from the corrosive solution after a magnitude of the corrosion current has a plunge. The apparatus includes a container containing the corrosive solution, and a driving device configured to move the probe precursor in the container through a fastener.

Abstract: The present disclosure relates to a field programmable gate array (FPGA)-based multi-channel dynamic light scattering (DLS) autocorrelation system and method. The system includes a DLS generation apparatus, a photon correlator, and a host computer, where the photon correlator includes an FPGA and a universal serial bus (USB) communication module; the DLS generation apparatus is connected to the FPGA; the FPGA is configured to count and perform correlation calculation on photon pulses generated by the DLS generation apparatus; the USB communication module is connected to the host computer; the FPGA includes a dual counter module and a correlation calculation module; the dual counter module is connected to the DLS generation apparatus and the correlation calculation module; the correlation calculation module is connected to the USB communication module; the dual counter module includes a plurality of dual counters; and the correlation calculation module includes a plurality of correlators.

Abstract: A sequencing method, system and kit of low molecular weight heparin (LMWH) oligosaccharides are provided.