Abstract:According to the optical system characteristics and the structure of a space solar telescope, a foeal plane focusing mechanism isdesigned to save the installation space and ensure the imaging quality. By using worm gear and eam chute groove as transmission parts,the circular motion of the stepping motor is transformed into linear motion in the normal direction of the focal plane. The focus range is 1.5 mm,the overall size is 167 mm×64 mm×94 mm and the mass is 2 kg. Two adjacent self-lubricating silicon nitride rings arearranged between the base back plate and the cam chute. It can increase the preloading foree without affecting the rotation of the camchute, improve the positioning accuracy to a certain extent, and reduce the backlash error. After that, the design scheme, resolution andself-locking eapability of the foeusing mechanism are introdueed in detail, and the error sourees, theoretical positioning accuraey andfinite element model simulation are analyzed. Finally, the positioning accuracy test and vibration test of the focusing mechanism arecarried out. The resultis show that the positioning accuracy is better than ±4.5 μm and the firsl-order mode is 349 Hz, which is hasicallyconsistent with the finite element simulation results. As a result, it has good dynamic stiffness and can effectively avoid resonancephenomenon. The encoder code values of the focusing mechanism are recorded before and after vibration test, which shows well self-loeking performanee. The focusing mechanism has the characteristics of small volume, large stiffness and high precision, which ean wellmeet the working conditions of space solar telescope.

Abstract:Due to the geometric error nfluence,the existing research mainly considers the geometric error compensation of end-mechanism or key moving-axis,lacks successive compensation of moving-axis-geometric-error.In order to avoid error accumulation effect caused by geometric error chain of on-machine inspection mechanism and effectively improve on-machine inspection accuracy,according to the on-machine inspection principle of the independently developed horizontal gear grinder,based on the multi-rigid body system kinematics and homogeneous coordinate transformation theory,the geometric error chain model of on-machine inspection mechanism is established. After the moving-axis-gcometic-errors of geometric error chain are identified and compensated step by step,the standard sample gear inspections of the gear grinder were carried out. Results show that before and afte error compensation,the tooth lead accuracies are both at level 4; afer erro compensation,the tooth profile accuracy is improved by 4 grades and is at level 4,which is consistent with the result of Gleaso inspections.The results verify the correctness of the model,which is expected to be used in high-precision on-machine inspection system of gear grinder.

Abstract:With the construetion of satellite-ground integrated communication network,the collaboration between space bonemicrosatellites and ground stations can achieve global coverage and high-speed transmission of signals. This new communication modeputs forward higher requirements for the stability and accuracy of the clock, which cannot be satisfied by using crystal oscillator.Combining with the requirements of satellite-ground integrated communication network and the excellent short-term frequency stability ofrubidium atomic frequency standard(RAFS), the miniaturization design of RAFS is carried out by using phase-locked microwavegeneration, direct digital frequency synthesizer, preamplifier, phase sensitive detection and TEon mode magnetron microwave cavity. The100 MHz phase-locked output function is added to RAFS to meet the requirements of communication payload on clock frequency as well.Performance analysis exhibits that the miniaturized low phase noise space borne RAFS has the characteristics of high stability, low phasenoise and wide operating temperature range. The weight of the product is 1.8 kg, the steady-state power consumption is 22 W, thefrequency slability of 100 MHz signal is σry(π)≤3×10⁻¹²x-¹²(1s≤r≤10000 s) and the phase noise @1 MHz is -162 dBc/Hz. TheRAFS can operate stably in orbit for a long time, which can be used as the clock source of communication satellite payload.

Abstract:The signal of checkweigher is affected by vibrations rising from the mechanical transmision systems, the measured object itselfand other random interferences. As a result, the signal-to-noise ratio of the sensor output is exeeptionally low, and the weighing resultsare dificult to meet the requirements of the national standards. To solve these prohlems, this paper combines the advantages of time-variant low-pass fiter and morphological filter, and proposes a novel fast data proceessing method. The time-variant low-pass fiter is usedfor one-stage filtering. The fiter parameters are optimized and adjusted iteratively when the signal changes, so that the edge signal canrespond quickly, the impact interference can be eliminated effeetively and the phase distortion of the weighing signal in the fiteringprocess can be suppressed. Then, an improved morphological filter is used to conduct the secondary filtering. By selecting zero-valuelinear structural elements, and opimizing the length of struetural elements and the weight eoefficient of the operator, the response speedof dynamie weighing is acceleratedl. Experimental results show that the proposed method can effectively suppress various interferences andimprove the weighing accuracy, Finally, a checkweigher system is constructed in this paper, which can achieve a maximum operatingspeed of 120 m/min and a maximum weighing of 400.0 g. It meets the requirements of the national standard“GB/T 27739-2011Automatie Catchweighing Instruments" category XIII Scale.

Abstract:Ball screw pair is widely used in machinery, aerospace and nuclear industry, ete. due to its high precision and highreliability. In traditional ball screw pair life calculation method, fatigue pitting is adopted as the failure criterion. While under theultimate load eonditions such as the aerospace, ball serew pair is required to bear nearly rated statie load in a short time, the main failuremode becomes plastic deformation failure rather than fatigue pitting failure, the traditional fatigue life theory and calculation methodbased on fatigue pitting are no longer applicable. Based on the plastie contact deformation characteristies of the ball serew pair, theconcept and caleulation method of fatigue elastic life (FEL) of the ball screw pair were proposed. On the basis of the rigid test bench ofthe ball serew pair, the FEL test method was designed and tested. It is found that the error of the FEL caleulation method proposed inthis study is within 15%,The sensitivity analysis shows that the conformity factor has the greatest impact on the FEL of the ball scerewpair, followed by the contact angle, the lead, the axial load and the pitch diameter of the serew, and the ball diameter has the smallestimpact.

Abstract:To salve the influenees of the tilt of optical windows and the residual air pressure in the vacuum cavity on the measurementaccuracy in the laser interferometrie air refractive index measurement based on the variable length vacuum cavity, this paper analyzes theerror caused by the optical window tilt when the vacauum cavity is pulled. And a method for detecting and compensating the tilt ermor ofwindows is proposed. In addition, the method of measuring and compensating the air residual pressure in the vacuum cavity is studied.To verify the effeetiveness of the proposed method, a laser interferometrie air refractive index measurement system based on the variablelength vacuum cavity is constructed, the measurement results with proposed method are eompared with the results obtained by Edlénequation, Experimental results show that, the measurement results of the two method are in good agreement. In 2.2 h and 20 min,thestandard deviations of the differences between the measurement results of the proposed method and that of the Edlen equation are 2.34×10and 2.89×10⁻°,respectively. This indicates that the proposed measurement error eompensation method of air refractive indexis feasible and effective, which can be applied to the real-time compensation of air refractive index in laser interferometrie precisiondisplacement measurement.

Abstract:Damage imaging based on laser-induced surface acoustice wave is one of the difficult points of laser ultrasonie nondestruetivetesting. There exist the problems such as low imaging resolution, poor imaging efect and high equipment requirements. Aiming at theseproblems, propose that the 2D time-delay superposition imaging algorithm is adopted to improve the imaging quality. Firstly, throughexperiment and simulation, a variely of signals generated in the process of laser ultrasonie scanning are systematically analyzed. Based onthis, the imaging algorithm of laser-induced surface acoustie wave is improved. In this paper, the reetangular erack defects and circulardefeets with depth gradient are set up. Then, the defeets are scanned, detected and imaged with the laser ultrasonic scanning platform.In the images, the morphologies of the rectangular crack defects and circular defects are clearly reflected. The imaging results show thatthe resolution of the 2D time-delay superposition imaging algprithm is significantly improved compared with that of the energy method.The full width at half maximum is no more than 0.3 mm; and the measurement erors of the radius of the cireular defects and the lengthof reetangular erack defects are no more than 0.4 mm. And the algorihm also has certain measurement ability for the defeet depth.

Abstract:Computed laminography imaging has its unique advantages in nondestructive testing of plate componenis, However, due to thelimited projection angle, there are limited-angle artifacts and blur in the sliced image. In order to improve the image quality of computedlaminography, a filtered back-pmojection algorithm based on projection view-weighting is proposed, which effectively suppresses theinterference of high-density features to other slices. Firstly, aceording to the dissimilarity among the sliced images from diferentprojeetion views, the weighing coeficients of different projeetion views are determined,and then the projeetion is reconstructed byweighted back-projcetion. Finally, the effeets of three different weighting eoefficients on the quality of reeonstrueted images are analyzed,and this paper takes the modulation of slice sensitivity profile as the quantitative evaluation index, the modulation of slice sensitivityprofiles for unweighted and three different weighting coefficients are 0.082,0.267,0.290 and 0.294,respectively. The experimentresults show that the proposed algorithm reduces the sliced image aliasing, the modulation of slice sensitivity profile is increased by about 0.2 and the quality of recnstrueted images is signifieantly improved.

Abstract:Magnetie Barkhausen noise is sensitive to stress, which is an in-situ non-destructive stress measurement technology withconvenient operation, high detection sensitivity and good repeatability. It has broad application prospect in residlual stress measurement,stress concentration zone evaluation of parts and bearing stress evaluation of struetures. The measurement of the maximum prineipal stressand its diretion during the measurement of the plane stress on the surface of ferromagnetic materials in engineering is an urgent problemto he solved. Proposes a plane stress measurement method based on the cireumferential magnetic Barkhausen noise distribution, andestablishes the solution of the plane stress tensor. The model realizes the demodulation of normal stress and shear stress in any direetionof the measuring point. Experiments have verified the effectiveness of this method. Measurement resulis show that when the principalstress is greater than 50 MPa, the measured maximum prineipal stress direction deviation is 10°, the maximum normal stress deviation is5 MPa and the maximum shear stress deviation is 6 MPa, which has high measurement accuracy

Abstract:Aiming at the urgent need of solving environmental temperature infuence in the complex impedance icing detection,analyzes the relaxation polarization process of ice, combines the experimental data to obtain the relationship between the complexpermittivity and temperature of ice, and proposes a temperature compensation method for complex impedance icing detection. In orderto improve the accuraey of temperature compensation and reduee the workload of calibration, implements an aceurate and reliabletemperature measurement compensation method through the analysis of the relaxation polarization theory and the construetion of atemperature drift model. It weakens the influenee of icing thickness on temperature compensation, and greatly reduces the complexityof temperature compensation for complex impedance parameters. Icing experiment results show that the proposed method can reducethe influence of temperature drift on the measurement results by more than 80% under ambient temperature of -24℃ to -3℃, whichsignifcantly imprmoves the compensation accuracy and calibration efficieney. The proposed method has certain value of engineeringapplieation.

Abstract:Selective laser meling(SLM) can be used for rapid forming of metal parts with arbitrary structure, but the internal structureand material properties of the parts are significantly different from traditional parts. The elastic constants and their distribution in differentdirections of SLM 316L stainless steel parts are characterized based on a dual-mode ultrasonie transducer. Firstly, a measurement systemof ultrasonie elastic constant distribution is built by designing and fabricating a high-performanee dual-mode ultrasonic transducer. Thelongitndinal wave and two orthogonal shear wave velocities of 316L stainless steel samples prepared by SLM are measured suecessively,and the elastic modulus and Poisson's ratio in different directions at the same position are obtained. Through the meusurement of soundvelocity in different forming directions, it is found that SLM parts show significant diference in the melted layer in the z direction ofstacking, showing obvious anisotropy. The distribution of elastic constants in the y-= plane shows that Young's modulus Ers is greaterthan Enz, and Poisson's ratio aris is less than Gris, and each melted layer of the part has similar elastic constant distribution rule. Inaddition, the influences of msin process parameters such as seanning speed and hateh space on the elastie constants are also discussed.The effeetive nondestructive characterization of elastie constants of selective laser meling parts will provide a technical basis for intemalquality control and process improvement of additive manufacturing parts.

Abstract:Aiming at the problem of different directions of erack defects on the surface of the pipeline, a crack detection method based onbalaneed electromagnetie technology is proposed. The eleetromagnetie distribution of the inmer surface of the pipeline under the time-harmonic electromagnetic field is analyzed by Maxwell's equations. According to the distortion of magnetie flux and induced current, thedeteetion mechanism and signal law of eracks in all directions on the pipeline surface are analyzed, and the effectiveness of the balancedeleetromagnetie technology for all angle detection of pipeline cracks is proved. The finite element method is used to caleulate and analyzethe electromagnetie distortion degree of the inner surface of the pipeline when the crack is at seven diferent angles to the detectiondirection, and the corresponding induced voltage signal is obtained through simulation, Aceording to the simulation result, the validitytest is carried out. Results show that the balaneed eleectromagnetie deteetion technology can realize the full angle detection of the surfaceerack of the pipeline. The deteetion signal feature is divided by the detection direction and the crack at an angle of 30°. The 0°~30°signal feature is the first trough followed by the peak. The amplitude of the detection signal gradually decreases as the angle increases,and the peak-to-valley spacing decrease rapidly, 30°~90° signal features a peak first and then a trough. The amplitude of the deteetionsignal gradually inereases as the angle inereases, and the peak-to-valley spacing slowly decreases; when the detection direction is 30°t0the crack, the indueed voltage signal has a double peak-valley feature, And the peak-to-peak value is the smallest. This method providesa theoretical basis and experimental hasis for the quantitative study of the erack angle on the pipe surface.

Abstract:Edge identification is an important task in the interpretation of potential field data and can be used in the field of resoureedeteetion and so on, which is one of the hot topics in current research. For deep anomalous targets, the traditional edge identificationmethods are prone to blur, divergence, deformation and other problems. Most of the improved methods use high-order derivatives,although they can well identify the deep anomaly boundary, the caleulation is complieated and easy to be disturbed by noises. In order toimprove the above problems, proposes a stable and fast edge identification method, which only uses sign funetion and gravity magneticvertical derivative data, can identify the targels at diferent depths in a balanced manner, and avoids the caleulation of higher-orderderivatives. Through experiments and comparisons of theoretical models,the convenience,effectiveness, anti-oblique magnetizationability and anti-noise ability of the method were verified. At the same time, through the application of actual data, it was verified that themethod ean accurately and clearly distinguish abnormal objeets in a complex gravity and magnetie environment, which ean save a lot oftime and energy of relevant researchers, and has a good application prospect.

Abstract:Based on the statistical moment theory derived from the single degree of freedom system, aiming at the large gap betweenidentifying the structure damage with model-free method and the practical application, ineorporates the generalized patterm searchalgorithm,proposes a new two-step hierarchieal rapid damage detection method for frame strueture, which takes fusing thefourth-order displacement moment and the eighth-order aceeleration moment as the index. The generalized pattern search algorithmcombines with the model-free rapid damage location theory to form a new damage deteetion method proposed. The numeriealsimulations of the 12-story frame structure numerical model with or without noise were carried out, and the deviations from thestandard results are all within 3%, which proves the accuracy and the anti-noise effect of this method. This method was comparedwith the two-norm optimization method and the quasi-Bayesian thinking method of statistical moments under the same index, theresults verify the superiority of the new method in accuracy, stability and fast deteetion calculation time of damage detection. Withthe test data of the 12-story standard frame vibration table, three typical working cases were selected for damage diagnosis, and theresults were compared with the actual test report and analyzed, the results show that compared with other methods, this method canrefleet the accumulated damage level change caused by the test working case accumulation better, which highlights the reliability of the new method in engineering detection.

Abstract:Aiming at the problem that the measurement error of power metering eyuipment is difficult to predict under multi-stressconditions, a measurement error prediction method of power metering equipment is proposed based on kernel support veetor regression(KSVR),and an Optimized Genetic Algorithm(OGA) is proposed to optimize the kemel parameters. Firstly, a linear weightedmulti-kermel fumetion is prmposed to fuse multiple stress features, and the kemel weight coefficient is used to deseribe the influence ofdiferent stresses on the power metering equipment. Then, in the parameter selection stage of the kermel function, to avoid the limitationof manual parameter adjustment, an OGA with crossover probability and mutation probability adaptive adjustment is proposed and appliedto the optimization selection issue of kernel parameters. The operation data analysis of the smart electricity meters in Xinjiang High DryHeat Test Base of State Grid shows that the proposed model has high aceuraey, the average mean square error of the prediction results is 0.00018,and the highest goodness of fit can reach 0.989, which can provide a targeted strategy for the health management of powermetering equipment under multiple environmental stresscs.

Abstract:In order to monitor the slate of complex industrial process in real time and predict the fault trend accurately, this paperpresents a fault prediction method based on denoising auto eneoder(DAE)and temporal convolutional network (TCN).Firstly,therandom forest algorithm is used to filter out the features related to faults. Then, the nonlinear features of input data are extracted and theoriginal features of input data are reconstructed, and the squared prediction error(SPE)statistics is established based on thereconstruetion error to reflect the slate characteristies of the faults. Finally, considering that the derivative of ReL.U activation funetion inthe residual module of TCN is zero in the negative interval, which may cause certain neurons to fail to activate, a Swish activationfunetion and filter response normalization-based temporal convolutional network (SFTCN) is proposed. By construeting the obtained SPEinto time series, the SPE predietion can he realized based on the SFTCN. Experiments are conducted with the data of Tennessee Eastman (TE) process and the life-ceycle vibration data of rolling bearings measured by the center for intelligent maintenance systems of theUniversity of Michigan. Results show that eompared with the unmodified TCN, the average absolute pereentage eror of the proposedmethod is redueed by at least 20.9%, which has high application value.

Abstract:The ejector has advantages of small size, no moving parts, no parasitie energy consumption, ete. It is becoming an idealsolution for hydrogen reeycling in hydrngen fuel eells. However, it is difficult to mateh and optimize the ejcector with the stack due to thehigh coupling between the ejector's circulating fluid and the supply fuid. In this paper, the combination of computation fluid dynamic(CFD) calculation and experiment is used to obtain multiple sels of different nozzle exit position(NXP) and working conditions underthe eoupling change of ejector ejeetion fluid pressure and back pressure under fuel cell variable load conditions. The internal pressurefield and velocity field of the ejector explore the evolution of the influence of the NXP variable operating conditions on the ejectorperformance. Results show that the increase of primary flow pressure is helpful to improve performance of the ejector. When the primarypressure is 4 bar, the ejeetion ratio reaches a peak of 2.43 when NXP is -15.6 mm. Meanwhile, based on the research results, thispaper utilizes numerical analysis to achieve the optimal NXP judgment method of the ejector under variable working conditions, which ishelpful to the matching design and optimization of the ejector and the stack under wide working conditions.

Abstract:Aiming at safety problems caused by abmormal collisions during robot force/position hybrid control,a collision detectionscheme based on rapid dynamies identification is proposed. Firstly, a rapid robot dynamics identification model is formulated. Thesimplest trigonometrie funetion regression matrix of the robot joint gravity moment is sorted based on Lagrangian method, and thecontinuous friction molel is used to model the joint friction. Then, both the minimum parameter set of the gravity moment and theparameler set of the continuous frietion model of the rmobot joint are identified by least square method. Finally,rapid dynamieidentifieation and collision detection experiments of the robot are designed and completed to evaluate the effectiveness of the proposedmethod. Results show that the proposed method can quickly and effeetively identify the dynamie paramelers of the robot. The abmomalcollisions above 4 N-m in position control and 8 N.m in force control can be detected in real time, which effectively guarantees the safetyof operators and equipment and has certain engineering reference value.

Abstract:For key low texture components of the transmission tower, most detection methods rely on the labeling and training of a largenumber of sample images, while these samples are usually scarce. Proposes a transferable deteetion method-PowerNet for the key lowtextured components. It combines Siamese network and eross-correlation convolution to fuse the features of sample block and searchregion,and effectively filters out the background of the component sample image using mask eropping, Finally, scoring candidate regionis proposed where the seale, location, and loU are adopted to improve the accuracy of detection. Experiments show that mask ermppingand sooring candidate region play an important role in accurate detection. According to AP⁵0 eriterion, the avernge accuracy rate of ourdeteetion method reaches 98%, which can detect various eomponents of the transmission tower concerning the varianee of view angle,scale, or illumination.

Abstract:Aiming at the situation that least squares support vector machine is sensitive to outliers and lacks robustmess, an improved leastsquares support vector machine algorithm considering sample outliers is proposed. The algorithm first ealeulates a LOF for each datasample using the loeal outlier factor detection algorithm, and can efectively divide the samples into normal and abnormal samplesaceording to their factor values, and then separately set sample weights for different samples. The algorithm effectively ensures that the weight of abnormal samples is reduced while the weight of normal samples is not affected, so that the least squares support vectormachine can achieve the optimization of the objective funetion while ensuring that the normal data information is not lost, so as to improvethe robustness of the model, Finally,"information entropy"and "average particle distance" are introduced to improve the particle swarmalgorithm, which is applied to the parameter optimization of the model. Experiment simmlation shows that the algorithm can effectivelyimprove the robustness of the model. With the increase of abmormal samples, the accuracy of the model is improved by about 67%.Keywords:improved least square support vector machines; loeal outlier factor deteetion algorithm; improved PSO algorithm

Abstract:In order to reduce missed and false deteetion of low contrast vessels in retinal vascular skeleton extraction, a mulli-scale retinalvascular skeleton extraction method based on principal curvature and principal direetion is proposed. Firstly, the principal curvature andprincipal direetion of each pixel in the retinal image is extracted after multi-scale Gaussian filtering. Secondly, the loeal maximum pointsin the direction of the maximum principal curvature are estracted at each scale, and the high eontrast vascular center pixel is selected asthe seed point by curvature threshold. Then, the minimum principal direetion is used to track and labeled the low eontrast vessels.Finally, the vascular skeleton estracted at multiple seales are fused. The proposed algorithm is evaluated on DRIVE training dataset,DRIVE test dataset and STARE dataset. The number of missed detection are 89, 97, and 106, respeetively. And the number of falsedeteetion are 99, 101, and 122, respectively, Experimental results show that the proposed method can extract small vascular skeletonswith low contrast, but there are a few miss deteetion for small blood vessels with contrast less than three gray levels, and a few falsedeteetion for fine stripe texture and lesions interference which adheres to blood vessels.

Abstract:Aceording to the eror source and the error amount obtained by the remote sensing imaging coupled typical error sourceinversion method, the imaging quality of the optieal system could be improved. The high-quality remote sensing image plays a great rolein the military and civilian fields, Based on the distorted remote sensing image, this study proposes a method for the coupled typical erorsouree inversion of remote sensing imaging. Firstly, according to the modulation transfer funetion model of the typical error source andthe decoupling principle of the coupled error source, the coupled typieal error decoupling equations are formulated. Then, the modulationtransfer function of remote sensing image is extracted by the edge method. The initial value of the coupled typical error source isdetermined based on the long-short term memory network. Finally, the Levenberg-Marquardt optimization algorithm is used to solve andcaleulate the coupled typical error decoupling equations. The typical error source and error amount are reversed. Experimental resultsshow that the relative eror between the inversion value and the true value of the coupled typical error of the distorted remote sensingimage is no more than 8%,most of which are below 5%. The method has excellent inversion performance.

Abstract:In order to present the defeels contained in two casting X ray DR images with diflerent grayscale window widths and windowlevels in one image, develops a kind of casting X-ray DR image fusion method based on weighted least squares filter and guided filter,One of the images is selected as the base image and the other image is selected as the detail image. The aforementioned two filters withedge-preserving property are utilized to extract the defeet information contained in the detail image. The weighted least squares filter isapplied to the base image and the output is taken as the frame, then the defects contained in the base image are separated by subtractingthe frame from the base image. The guiding fiter is used to sum the two types of defeet information with weights. Finally, the frame isused to carry the results of the weighted summation to get the fused image. Experiment results show that the obtained fused result candisplay 5 defects of two casting DR images with different grayscale window widths and window levels or 7 defeets of three casting DRimages with different grayscale window widths and window levels. The method presented in this paper can be applied to the radiographicnondestruetive testing of castings.

Abstract:Fixing the monocular camera and the inertial measurement unit (IMU) on the end of the robotic arm is an effective method torealize the motion estimation and scene perception. Reliable and aceurate calibration hetween monocular camera, IMU and robotie arm isthe prerequisite for realizing follow-up perception. However, traditional calibration method has the problems of large coupling error, poorcalibration consisteney and insufficient 6-DOF exeitation. Therefore,this paper proposes a novel monocular camera-IMU-mamipulatorspace joint ealibration method, which can completely decouple the errors of the rotation component and the translation component. At thesame time, this paper innovatively designs a spiral motion trajectory to ealibrate the perception module. Using such a calibrationtrajectory can avoid the problems of insufficient 6-DOF excitation and poor consisteney in traditional calibration methods. In theexperimental link, a monocular camera-IMU-manipulator space joint ealihration platform is built, and the mot mean square errors of yaw-pitch-roll rolation and x-y-z translation are ealeulated to be less than 0.7°and 7 mm, respectively, which proves the effeetiveness of thecalibration method proposed in this paper.

Abstract:Data acquisition is an essential poeedure affecting the efficieney and accuracy of the experiment in mass spectrometry analysis. Compared with the traditional data acquisition methods, the data independent acquisition technolggy emerging in recent yearshas the advantages of high throughput,high eoverage and high aceuraey,which has hecome a powerful tool for proteomics, metabolite quantitative and omics researeh, and has important referenee value in the field of food analysis. The principles of the curent main datain dependent acquisition and recent advance in data processing were reviewed as well as the potential of non-targeted screening in food analysis was highlighted. Furthermore,the application of non-targeted screening data independent acquisition in analysis of food safety,food anthenticity and funetional active ingredients was summarized. Finally, the challenges and future trends of data independent acquisition in food analysis was discussed.

Abstract:The generalized inverse beamforming has attracted wide alttention due to its high spatial resolution and strong sidelobesuppression eapabiliies. To improve the sound souree identifieation performance of GIB, a regularized beamforming method via elasticnet is proposed, which ean ensure the robustness and sparsity of the sound souree identification results, However, the ineoherent noisegenerated in the proeess of measuring the sound source signal may produces unavoidable errors. To suppress the interference noise in themeasurement process, a generalized inverse beamforming method with improved elastie net regularization is proposed by combiningdiagonal denoising with improved eigenvalue method to reconstruct the regularization parameters of beamforming, which could distinguishthe interference noise from the target sound source. Numerical simulation and experimental results both prove that the main lobe widtherror of the proposed algorithm is less than 10 dB at high frequencies, and it has higher spatial resolution and robustness, and strongsidelobe attemuation ability than elastie net regularized heamforming as well.

Abstract:During the process of electrolytie extraction of metal from aqueous solutions, short-eireuiting eleetrodes could reduceeletrolysis current efficieney, inerease power consumption,and reduce the quality of cathode produets. The change of electrodecurent is the most effective way to monitor electrode short circuit. Due to the harsh electrolysis environment, the complexelectromagnetie field distribution, and the large number of electrodes, there are curmently lack of effeetive online eleetrode currentmeasurement methods. This paper proposes a method of measuring electrode current, which uses a linear Hall sensor to detect themagnetice induetion under the electrode in real time. The decoupling mathematical model among the Hall potential, magnetic induetionand current is utilized to caleulate the current flowing through the conduetive rod. In the laboratory, conductive rods are used insteadof electrodes to build an electrolytie cell for testing. Results show that when the total current flowing through the conduetive rods varieslinearly between 10 and 100 A, the current of a single conduetive rod measured by the proposed method is comparable to the clamp.The deviation of the measured value of the shape meter is within 1 A. And the measurement eror is within 2%.The currentmeasurement system has high accuracy and ean be used for on-line measurement of electrode currents in electrolyzers of metal aqueoussolutions such as copper and zine.

Abstract:In order to solve the problem of multi-component monitoring in oil produetion, based on optical fiher technology and electricalconductanee technology, suecessfully develops a fiber-optie and conductanee integrated sensor for muli-ceomponent monitoring inpetroleum production. FOCIS simulation model is estahlished using ZEMAX ray tracing method and FEM method. The electrie fielddistribution of the conduclance measurement module(CMM), CMM response characteristics, the retum light intensity distribution ofoptical fber measurement module(OFMM) and OFMM response characteristics, ete. are simulated and analyzed. The measured valuesof CMM and OFMM show a good linear relationship with the standard rates of phase content under diferent oil-gas-water three-phase flowpattems, and the erors of the measured rates of phase content are all within 5%,The FOCIS on site experiment test was caried out ina vertical pipeline with an inner diameter of 32mm. The experiment results show that under the working conditions where the gas flow rate is 5, 20,40m³/d,the total oil and water flow rate is 10, 30,50,70 m³/d and the liquid phase water content is 50%,60%,70%,80%,90%,the erors of the measured rate of water content and rate of gas content are wihin 5%。Both simulations and experimentsprove that the FOCIS muli-component monitoring of oil, gas and water is feasible and effective

Abstract:With the development of ultra high-vollage technology in our country, the measurement of intensive power frequeney cleetricfield has become more and more important. In order to suit the measurement reruirement of the intensive power frequency electrie field,based on the Poeckels effeet, a polarization-maintaining fiber eoupling type lithium niobate crystal intensive power frequeney electrie fieldsensor is designed, fabrieated and experimentally investigated, The optical input and output of the sensor are carried out through thecoupling of the polarization-maintaining fiber(PMF) collimators, which avoids the use of polarizer, 1/4 wave plate and other separatedoptical components. As a reult, the optical coupling efficieney of the sensor is improved to 66.7%。In addition, through twisting thePMF at 1/2 beat length in the font end of the input PMF collimator by 90°, the static operating point of the sensor can be set to m/2,which makes the sensor work in the nearly linear region. The intensive power frequeney electrie field was used to test the input/outputcharacteristics of the sensor. It is concluded that the linear measurable range of the sensor is 10.5~527 kV/m, the linear correlationcoeficient is 0.9986 and the linear dynamic range is 34 dB. Compared with the existing lithium niobate erystal intensive electrie fieldsensor, the sensor developed has the advantages of simple and compaet structure, and high coupling efficieney, which provides a newsolution for the measurement of power frequency intensive electric field in the time domain.

Abstract:Aiming at the problems of poor environmental noise suppression effect and low accuracy of wind speed and directionmeasurement in the existing ultrasonie wind measurement system in practieal application, an array ultrasonie sensor based on high-ordercumulant is proposed to measure wind speed and direction. The proposed method adopls the structure of an ultrasonie wind measurementsystem, which consists of an ultrasonie transmitting aray and five ulirasonic receiving array elements. On the structure of the system,muli-signal clasification(MUSIC)algorithm based on the high-orler cumulant is adopted to realize the effective measurement of windspeed and direction under Gaussian white noise or Gaussian mixed noise, which can effectively suppress the interference of whiteGausian noise and color noise. Compared with wind measurement method using correlation algorithm, the proposed method has highernoise suppression ability and higher measurement accuraey of wind speed and direction. Finally, the effectiveness of the proposed methodis verified and analyzed through simulation experiments and measured data verification experiments. Experimental results show that themeasurement errors of wind speed and wind dircetion Angle are 2.3% and-2°,respectively, which basically meet the technicalrequirements of ultrasonic wind measurement methods.