Fertilizer sphericity is an important assessment index of appearance quality that affects the fertilization effect.A fertilizer sphericity measuring device based on machine vision was designed aimed at low precision a...Fertilizer sphericity is an important assessment index of appearance quality that affects the fertilization effect.A fertilizer sphericity measuring device based on machine vision was designed aimed at low precision and heavy workload of manual fertilizer measurement,and high cost and complicated operation of high precision measuring instruments.A fertilizer sphericity measuring method based on equatorial and meridian circles was proposed.The device works in an intermittent static acquisition mode to simultaneously obtain both top and side images of a single fertilizer.First,the method performs gamma correction on the top and side images of the single fertilizer,and uses the Canny operator to detect the edge of the image to obtain the equatorial and meridian circular contour images of the fertilizer.Second,based on the fertilizer equatorial and meridian circular contour,the Least Squares Circle method was used to evaluate the roundness of the single fertilizer.Finally,the average roundness value of the equatorial and meridian circles was used as the final sphericity value of the fertilizer.The sphericity measurement test was carried out on the same batch of compound,organic and biological fertilizers by using the sphericity measuring device.The fertilizer sphericity data were obtained by different measurement and evaluation methods.The variation coefficient was used to evaluate the difference in fertilizer sphericity measured by different sphericity measurement and evaluation methods.The results show that among the different measurement and evaluation methods,the coefficient of variation of fertilizer sphericity measured by the equatorial and meridian circle method was the smallest,and the coefficient of variation of sphericity measured by the Least Squares Circle method was the smallest and accurate.This study shows that the sphericity measuring device and method can accurately measure the fertilizer sphericity,and has a significant potential to facilitate fertilizer production and quality inspection.展开更多
This paper presents the study and application of the electronic device anti-interference techniques underhigh voltage and/or heavy current electro-magnetic circumstance in power system.[
We have reviewed a set of recently published studies that compared the anterior chamber depth（ACD） and/or white-to-white（WTW） distance obtained by means of different measuring devices.Since some of those studies r...We have reviewed a set of recently published studies that compared the anterior chamber depth（ACD） and/or white-to-white（WTW） distance obtained by means of different measuring devices.Since some of those studies reached contradictory conclusions regarding device interchangeability,this review was carried out in attempting to clarify which clinical devices can or cannot be considered as interchangeable in clinical practice to measure ACD and/or WTW distance,among these devices：A-scan,ultrasound biomicroscopy,Orbscan and Orbscan Ⅱ（Bausch＆Lomb Surgical Inc.,San Dimas,California,USA）,Pentacam and Pentacam HR（Oculus,Wetzlar,Germany）,Galilei（Ziemer,Switzerland）,Visante optical coherence tomography（Visante OCT,Carl Zeiss Meditec Inc.,Dublin,California,USA）,lOLMaster（Carl Zeiss Meditec,Jena,Germany）,and Lenstar LS 900/Biograph（Haag-Streit AG,Koeniz,Switzerland/Alcon Laboratories Inc.,Ft Worth,Texas,USA）.展开更多
Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detect...Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evalualed by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 um. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.展开更多
On the one hand,existing measurement device independent quantum key distribution(MDI-QKD)protocols have usually adopted single photon source(SPS)and weak coherent photon(WCP),however,these protocols have suffered from...On the one hand,existing measurement device independent quantum key distribution(MDI-QKD)protocols have usually adopted single photon source(SPS)and weak coherent photon(WCP),however,these protocols have suffered from multi-photon problem brought from photon splitter number attacks.On the other hand,the orbital angular momentum(OAM)-MDI-QKD protocol does not need to compare and adjust the reference frame,solving the dependency of the base in the MDI-QKD protocol.Given that,we propose the OAM-MDI-QKD protocol based on the parametric light sources which mainly include single-photon-added-coherent(SPACS)and heralded single-photon sources(HSPS).Due to the stability of OAM and the participation of parametric light sources,the performance of MDI-QKD protocol gradually approaches the ideal situation.Numerical simulation shows that compared with WCP scheme,HSPS and SPACS schemes have increased the maximum secure transmission distance by 30 km and 40 km respectively.展开更多
An optical readout uncooled infrared detector, employing a substrate-free focal plane array with pitch size 60μm, is established. The reflector deformation induced by the stress mismatching of the bi-layer structure ...An optical readout uncooled infrared detector, employing a substrate-free focal plane array with pitch size 60μm, is established. The reflector deformation induced by the stress mismatching of the bi-layer structure is discussed and, in turn, a universal solution to determine both the optical readout sensitivity and the optimal filter position is found. By applying this solution, the optical readout sensitivity for the ideal plane reflector could theoretically increase by 80% as compared with the conventional operation, and the sensitivity loss caused by the reflector deformation can also be reduced to a reasonable level.展开更多
Bending and first flexural mode vibration behavior of electrostatic actuated nanometer-sized interdigitated cantilever arrays are characterized under vacuum conditions. The pull-in＇＇ effect in dc driving and the har...Bending and first flexural mode vibration behavior of electrostatic actuated nanometer-sized interdigitated cantilever arrays are characterized under vacuum conditions. The pull-in＇＇ effect in dc driving and the hard spring effect＇＇ in ac driving are observed. A mass sensitivity of 20 fg is expected for our devices due to the ultra-small mass of the arm and relative high Q factor. The mass-spring lump model combined with Green＇s function method is used to fit the dc driving behaviors including the pull-in voltage. For the ac driving case, the polynomial expansion of the capacitive force is used in the model. The successfully fittings of the pull-in voltage and the hard spring effect prove that our simulation method could be used for guiding the geometrical design of cantilever-based sensors.展开更多
A three-dimensional finite element model for phase change random access memory （PCRAM） is established for comprehensive electrical and thermal analysis during SET operation. The SET behaviours of the heater additio...A three-dimensional finite element model for phase change random access memory （PCRAM） is established for comprehensive electrical and thermal analysis during SET operation. The SET behaviours of the heater addition structure （HS） and the ring-type contact in bottom electrode （RIB） structure are compared with each other. There are two ways to reduce the RESET current, applying a high resistivity interracial layer and building a new device structure. The simulation resuIts indicate that the variation of SET current with different power reduction ways is little. This study takes the RESET and SET operation current into consideration, showing that the RIB structure PCRAM cell is suitable for future devices with high heat efficiency and high-density, due to its high heat efficiency in RESET operation.展开更多
The accurate evaluation of the lodging resistance of maize plants can provide a basis for the breeding of lodging-resistant cultivars and the regulation of cultivation measures.However,the traditional methods for eval...The accurate evaluation of the lodging resistance of maize plants can provide a basis for the breeding of lodging-resistant cultivars and the regulation of cultivation measures.However,the traditional methods for evaluating maize lodging resistance in terms of plant morphology and stalk mechanical strength have certain limitations.The objective of this research was to develop a device for determining the critical wind speed of maize stalk breaking.The device was equipped with a centrifugal fan to supply airflow and was powered by a frequency conversion motor.The frequency converter adjusted the motor speed and thus adjusted the wind speed.The wind speed decreased first and then increased with increasing height above the outlet of the device,and maximum wind speed can reach 40 m/s.This device was convenient for transportation in the field,has a low cost,and can quickly,accurately,and objectively determine the lodging resistance.Field tests showed that the device ran stably for a long time.The coefficient of variation of three repeated measurements was between 1.5%and 4.8%for four maize cultivars.The new device can measure the critical wind speed of maize lodging and identify the lodging resistance for different maize cultivars,cultivation practices,and plant health conditions,and can thus overcome barriers to measuring the maize lodging resistance under natural wind conditions.展开更多
Reference frame independent and measurement device independent quantum key distribution(RFI-MDI-QKD)has the advantages of being immune to detector side loopholes and misalignment of the reference frame.However,several...Reference frame independent and measurement device independent quantum key distribution(RFI-MDI-QKD)has the advantages of being immune to detector side loopholes and misalignment of the reference frame.However,several former related research works are based on the unrealistic assumption of perfect source preparation.In this paper,we merge a loss-tolerant method into RFI-MDI-QKD to consider source flaws into key rate estimation and compare it with quantum coin method.Based on a reliable experimental scheme,the joint influence of both source flaws and reference frame misalignment is discussed with consideration of the finite-key effect.The results show that the loss-tolerant RFI-MDI-QKD protocol can reach longer key rate performance while considering the existence of source flaws in a real-world implementation.展开更多
Based on the Mg^(2+)complexation with acid chrome blue K(ACBK)at pH 10.2,an automatic system was designed to determine total hardness of water.The system consists of a vector colorimeter,a multi-channel sampling pump ...Based on the Mg^(2+)complexation with acid chrome blue K(ACBK)at pH 10.2,an automatic system was designed to determine total hardness of water.The system consists of a vector colorimeter,a multi-channel sampling pump and both reagents A and B.Two kinds of reagent solutions were prepared and used in this system,i.e.,ammoniacal buffer and ACBK—disodium magnesium EDTA solutions.The experimental results of the standard solutions containing 2 and 3 mg/L of total hardness showed that the relative standard deviations(RSDs)were 1.9%and 2.2%,respectively,and the limit of detection(LOD)was only 0.035 mg/L.The detection of four natural water samples showed that the recoveries were between 85.0%and 108.6%,consistent with those obtained by ICP-AES method.展开更多
The disturbance torque generated via solar array drive assembly(SADA) can significantly degrade the key performance of satellite.The discussed SADA is composed of a two-phase hybrid stepping motor and a set of two-sta...The disturbance torque generated via solar array drive assembly(SADA) can significantly degrade the key performance of satellite.The discussed SADA is composed of a two-phase hybrid stepping motor and a set of two-stage straight gear reducer. Firstly, the vibration equation of the two-phase hybrid stepping motor is established via simplifying and linearizing the electromagnetic torque.Secondly, based on the vibration equation established, the disturbance torque model of SADA is created via force analysis and force system simplification. Thirdly, for precisely ground measuring the disturbance torque aroused by SADA, a measurement system,including a strain micro-vibrations measurement platform(SMMP) and a set of gravity unloading device(GUD), is designed.Fourthly, the proposed disturbance torque model is validated by measuring and simulating the disturbance torque produced via SADA driving rigid load through GUD. The results indicate that, the proposed disturbance torque model holds the ability to describe the disturbance torque caused by SADA with high precision. Finally, the disturbance torque emitted by SADA driving a flexible load, designed to simulate solar array, is modeled and simulated via using fixed-interface mode synthesis method(FIMSM). All the conclusions drawn from this article do have a meaningful help for studying the disturbance torque produced by SADA driving solar array on orbit.展开更多
基金This work was supported in part by the National Key Research and Development Plan of China(2016YFD0201104),National Apple Industry Technology System Project.
文摘Fertilizer sphericity is an important assessment index of appearance quality that affects the fertilization effect.A fertilizer sphericity measuring device based on machine vision was designed aimed at low precision and heavy workload of manual fertilizer measurement,and high cost and complicated operation of high precision measuring instruments.A fertilizer sphericity measuring method based on equatorial and meridian circles was proposed.The device works in an intermittent static acquisition mode to simultaneously obtain both top and side images of a single fertilizer.First,the method performs gamma correction on the top and side images of the single fertilizer,and uses the Canny operator to detect the edge of the image to obtain the equatorial and meridian circular contour images of the fertilizer.Second,based on the fertilizer equatorial and meridian circular contour,the Least Squares Circle method was used to evaluate the roundness of the single fertilizer.Finally,the average roundness value of the equatorial and meridian circles was used as the final sphericity value of the fertilizer.The sphericity measurement test was carried out on the same batch of compound,organic and biological fertilizers by using the sphericity measuring device.The fertilizer sphericity data were obtained by different measurement and evaluation methods.The variation coefficient was used to evaluate the difference in fertilizer sphericity measured by different sphericity measurement and evaluation methods.The results show that among the different measurement and evaluation methods,the coefficient of variation of fertilizer sphericity measured by the equatorial and meridian circle method was the smallest,and the coefficient of variation of sphericity measured by the Least Squares Circle method was the smallest and accurate.This study shows that the sphericity measuring device and method can accurately measure the fertilizer sphericity,and has a significant potential to facilitate fertilizer production and quality inspection.
文摘This paper presents the study and application of the electronic device anti-interference techniques underhigh voltage and/or heavy current electro-magnetic circumstance in power system.[
文摘We have reviewed a set of recently published studies that compared the anterior chamber depth（ACD） and/or white-to-white（WTW） distance obtained by means of different measuring devices.Since some of those studies reached contradictory conclusions regarding device interchangeability,this review was carried out in attempting to clarify which clinical devices can or cannot be considered as interchangeable in clinical practice to measure ACD and/or WTW distance,among these devices：A-scan,ultrasound biomicroscopy,Orbscan and Orbscan Ⅱ（Bausch＆Lomb Surgical Inc.,San Dimas,California,USA）,Pentacam and Pentacam HR（Oculus,Wetzlar,Germany）,Galilei（Ziemer,Switzerland）,Visante optical coherence tomography（Visante OCT,Carl Zeiss Meditec Inc.,Dublin,California,USA）,lOLMaster（Carl Zeiss Meditec,Jena,Germany）,and Lenstar LS 900/Biograph（Haag-Streit AG,Koeniz,Switzerland/Alcon Laboratories Inc.,Ft Worth,Texas,USA）.
基金This project is supported by Science and Technology Development Foundation of Shanghai Municipal Commission of Science and Technology, China (No.021111125).
文摘Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evalualed by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 um. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.
基金Hong Lai has been supported by the National Natural Science Foundation of China(No.61702427)the Chongqing innovation project(No.cx2018076)+1 种基金the Fundamental Research Funds for the Central Universities(XDJK2018C048)the financial support in part by the 1000-Plan of Chongqing by Southwest University(No.SWU116007)。
文摘On the one hand,existing measurement device independent quantum key distribution(MDI-QKD)protocols have usually adopted single photon source(SPS)and weak coherent photon(WCP),however,these protocols have suffered from multi-photon problem brought from photon splitter number attacks.On the other hand,the orbital angular momentum(OAM)-MDI-QKD protocol does not need to compare and adjust the reference frame,solving the dependency of the base in the MDI-QKD protocol.Given that,we propose the OAM-MDI-QKD protocol based on the parametric light sources which mainly include single-photon-added-coherent(SPACS)and heralded single-photon sources(HSPS).Due to the stability of OAM and the participation of parametric light sources,the performance of MDI-QKD protocol gradually approaches the ideal situation.Numerical simulation shows that compared with WCP scheme,HSPS and SPACS schemes have increased the maximum secure transmission distance by 30 km and 40 km respectively.
基金Supported by grants from by the Natural Science Foundation of China under Grant Nos 10732080, 10627201 and 10872191, and the National Basic Research Program of China under Grant No 2006CB300404.
文摘An optical readout uncooled infrared detector, employing a substrate-free focal plane array with pitch size 60μm, is established. The reflector deformation induced by the stress mismatching of the bi-layer structure is discussed and, in turn, a universal solution to determine both the optical readout sensitivity and the optimal filter position is found. By applying this solution, the optical readout sensitivity for the ideal plane reflector could theoretically increase by 80% as compared with the conventional operation, and the sensitivity loss caused by the reflector deformation can also be reduced to a reasonable level.
文摘Bending and first flexural mode vibration behavior of electrostatic actuated nanometer-sized interdigitated cantilever arrays are characterized under vacuum conditions. The pull-in＇＇ effect in dc driving and the hard spring effect＇＇ in ac driving are observed. A mass sensitivity of 20 fg is expected for our devices due to the ultra-small mass of the arm and relative high Q factor. The mass-spring lump model combined with Green＇s function method is used to fit the dc driving behaviors including the pull-in voltage. For the ac driving case, the polynomial expansion of the capacitive force is used in the model. The successfully fittings of the pull-in voltage and the hard spring effect prove that our simulation method could be used for guiding the geometrical design of cantilever-based sensors.
文摘A three-dimensional finite element model for phase change random access memory （PCRAM） is established for comprehensive electrical and thermal analysis during SET operation. The SET behaviours of the heater addition structure （HS） and the ring-type contact in bottom electrode （RIB） structure are compared with each other. There are two ways to reduce the RESET current, applying a high resistivity interracial layer and building a new device structure. The simulation resuIts indicate that the variation of SET current with different power reduction ways is little. This study takes the RESET and SET operation current into consideration, showing that the RIB structure PCRAM cell is suitable for future devices with high heat efficiency and high-density, due to its high heat efficiency in RESET operation.
基金This study was supported by the National Key Research and Development Program of China(Grant No.2018YFD0100206)the Central Public-interest Scientific Institution Basal Research Fund(Grant No.Y2019PT07)+1 种基金the China Agriculture Research System(CARS-02-25)the Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences.
文摘The accurate evaluation of the lodging resistance of maize plants can provide a basis for the breeding of lodging-resistant cultivars and the regulation of cultivation measures.However,the traditional methods for evaluating maize lodging resistance in terms of plant morphology and stalk mechanical strength have certain limitations.The objective of this research was to develop a device for determining the critical wind speed of maize stalk breaking.The device was equipped with a centrifugal fan to supply airflow and was powered by a frequency conversion motor.The frequency converter adjusted the motor speed and thus adjusted the wind speed.The wind speed decreased first and then increased with increasing height above the outlet of the device,and maximum wind speed can reach 40 m/s.This device was convenient for transportation in the field,has a low cost,and can quickly,accurately,and objectively determine the lodging resistance.Field tests showed that the device ran stably for a long time.The coefficient of variation of three repeated measurements was between 1.5%and 4.8%for four maize cultivars.The new device can measure the critical wind speed of maize lodging and identify the lodging resistance for different maize cultivars,cultivation practices,and plant health conditions,and can thus overcome barriers to measuring the maize lodging resistance under natural wind conditions.
基金supported by the State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)(No.IPOC2021ZT10)the National Natural Science Foundation of China(No.11904333)the Fundamental Research Funds for the Central Universities(No.2019XD-A02)。
文摘Reference frame independent and measurement device independent quantum key distribution(RFI-MDI-QKD)has the advantages of being immune to detector side loopholes and misalignment of the reference frame.However,several former related research works are based on the unrealistic assumption of perfect source preparation.In this paper,we merge a loss-tolerant method into RFI-MDI-QKD to consider source flaws into key rate estimation and compare it with quantum coin method.Based on a reliable experimental scheme,the joint influence of both source flaws and reference frame misalignment is discussed with consideration of the finite-key effect.The results show that the loss-tolerant RFI-MDI-QKD protocol can reach longer key rate performance while considering the existence of source flaws in a real-world implementation.
基金supported by both the Foundation(PCRRK21005)of State Key Laboratory of Pollution Control and Resource Reuse(Tongji University)The National Key Research and Development Program of China(2019YFC1805300)
文摘Based on the Mg^(2+)complexation with acid chrome blue K(ACBK)at pH 10.2,an automatic system was designed to determine total hardness of water.The system consists of a vector colorimeter,a multi-channel sampling pump and both reagents A and B.Two kinds of reagent solutions were prepared and used in this system,i.e.,ammoniacal buffer and ACBK—disodium magnesium EDTA solutions.The experimental results of the standard solutions containing 2 and 3 mg/L of total hardness showed that the relative standard deviations(RSDs)were 1.9%and 2.2%,respectively,and the limit of detection(LOD)was only 0.035 mg/L.The detection of four natural water samples showed that the recoveries were between 85.0%and 108.6%,consistent with those obtained by ICP-AES method.
文摘The disturbance torque generated via solar array drive assembly(SADA) can significantly degrade the key performance of satellite.The discussed SADA is composed of a two-phase hybrid stepping motor and a set of two-stage straight gear reducer. Firstly, the vibration equation of the two-phase hybrid stepping motor is established via simplifying and linearizing the electromagnetic torque.Secondly, based on the vibration equation established, the disturbance torque model of SADA is created via force analysis and force system simplification. Thirdly, for precisely ground measuring the disturbance torque aroused by SADA, a measurement system,including a strain micro-vibrations measurement platform(SMMP) and a set of gravity unloading device(GUD), is designed.Fourthly, the proposed disturbance torque model is validated by measuring and simulating the disturbance torque produced via SADA driving rigid load through GUD. The results indicate that, the proposed disturbance torque model holds the ability to describe the disturbance torque caused by SADA with high precision. Finally, the disturbance torque emitted by SADA driving a flexible load, designed to simulate solar array, is modeled and simulated via using fixed-interface mode synthesis method(FIMSM). All the conclusions drawn from this article do have a meaningful help for studying the disturbance torque produced by SADA driving solar array on orbit.
