The corrosion behaviors of copper and copper/titanium galvanic couple (GC) in seawater were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques in conjunction with s...The corrosion behaviors of copper and copper/titanium galvanic couple (GC) in seawater were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques in conjunction with scanning electron microscopy (SEM) method. The results show that the corrosion process of copper in seawater can be divided into two stages, in which corrosion resistance and SE show the same evolution trend of initial increase and subsequent decrease, while SG changes oppositely. However, the ensemble corrosion process of copper/titanium GC in seawater includes three stages, in which corrosion resistance and SE show the evolution features of initial decrease with a subsequently increase, and the final decrease again;while SG changes oppositely. The potential difference between copper and titanium in their galvanic couple can accelerate the initiation of pitting corrosion of copper, and both the minimum and maximum corrosion potentials of copper/titanium GC are much more positive than those of pure copper.展开更多
We recorded and described the calls and acoustic characteristics of the male tiger frog,Hoplobatrachus rugulosus,in an artificial pond during mating season.Spectral and temporal call parameters,along with call intensi...We recorded and described the calls and acoustic characteristics of the male tiger frog,Hoplobatrachus rugulosus,in an artificial pond during mating season.Spectral and temporal call parameters,along with call intensity were analyzed.Three harmonics were distinguishable from the spectrogram.Four patterns of dominant frequency were found in calls produced late at night,i.e,3 patterns in the first harmonic(located in 500 Hz section,700 Hz section,and 800 Hz section respectively) and 1 in the second harmonic(located in 1 800 Hz section).Call duration,call duty cycle,call intensity,and pulse rate were highly variable among different patterns of dominant frequency.These call properties could provide valuable evidence for further ecological study of this species.展开更多
Effects of reflowing temperature and time on the alloy layer of tinplate and its electrochemical behavior in 3.5%NaCl solution were investigated by electrochemical measurements and surface characterization.It is found...Effects of reflowing temperature and time on the alloy layer of tinplate and its electrochemical behavior in 3.5%NaCl solution were investigated by electrochemical measurements and surface characterization.It is found that the amount of alloy layer increases with the increase of reflowing temperature and time.Then the corrosion potential of detinned tinplate shifts positively and the corrosion rate decreases.After being coupled with tin,the detinned tinplate acts as cathode and tin acts as anode initially.However,after being exposed for some time,the potential shifts of both detinned tinplate and tin reverse the polarity of the coupling system.The galvanic current density decreases with the increase of reflowing temperature and time.展开更多
To investigate the diffusion reaction between Ti/Al solid diffusion couple, Ti/Al alternate foils formed by hot pressing were annealed at 525, 550, 575 and 600 °C for time ranging from 1 to 40 h. The experimental...To investigate the diffusion reaction between Ti/Al solid diffusion couple, Ti/Al alternate foils formed by hot pressing were annealed at 525, 550, 575 and 600 °C for time ranging from 1 to 40 h. The experimental results show that TiAl3 was the only observed phase at Ti/Al interface. The interface thermodynamics favored the preferential formation of TiAl3 in Ti/Al couple. The growth of TiAl3 layer occurred mainly towards Al foil side and exhibited a parabolic law. Using the interdiffusion coefficients calculated based on the contribution of grain boundary diffusion, the growth of TiAl3 was simulated numerically with the finite difference method, and the simulated results were in good agreement with the experimental ones.展开更多
The mating calls of six forms belonging to four genera Megophrys,Oreloalax,Scutiger and Leptolalax were recorded in Wawu Mountain National Forest Park,Sichuan Province of China,using cassette tape recorder (Aiwa) and ...The mating calls of six forms belonging to four genera Megophrys,Oreloalax,Scutiger and Leptolalax were recorded in Wawu Mountain National Forest Park,Sichuan Province of China,using cassette tape recorder (Aiwa) and Sony tape with an external microphone.All recordings were analyzed with an IBM PC based 'SIGNAL' software analysis system (Engineering Design,USA).The range of analyzed frequency was set as 0-10 kHz.Acoustic analysis shows that the dominant frequency of L.oshanensis,M.minor,M.sp.,S.(S.)chintingensis,O.omeimontis,and O.schmidti is 4521.9,3456.4,2293.8,1076.5,1071.0 and 1849.4 Hz on average respectively;the note duration is 46.2,90.8,99.6,72.2,78.8 and 110.3 millisecond on average respectively;the note interval is 140.4,253.0,681.4,1517.7,461.3 and 619.5 millisecond on average respectively.One-Way ANOVA analysis indicates that there are significant differences among the analyzed six forms on the dominant frequency,the note duration,and the note interval (P<0.01).Multiple comparisons using Least-Significant Difference (LSD) show that the difference of the dominant frequency between S.(S.) chintingensis and O.omeimontis is not significant (P=0.917>0.05);on the note duration,only L.oshanensis is significantly different from M.minor,M.sp.,O.omeimontis and O.schmidti (P<0.01);on the note interval,L.oshanensis is not significantly different from M.minor,the same with M.sp.versus O.schmidti and O.omeimontis versus O.schmidti (P>0.05).Correlation analysis indicates that there are no significant correlation among the three acoustic characters of dominant frequency,note duration and note interval,and two environmental factors of the elevation and air temperature (P>0.05) except that the note interval is significantly linear correlated with the elevation (r=0.943,P=0.005<0.01).In the light of above,it is suggested that acoustic characteristics of calls are useful in distinguishing forms;the change of the note interval with the elevation may be a kind of strategy of reproduction.展开更多
Based on the magnetic interaction energy, using derivative of the magnetic energy density, a model is proposed to compute the magnetic-induced shear modulus of magnetorheological elastomers. Taking into account the in...Based on the magnetic interaction energy, using derivative of the magnetic energy density, a model is proposed to compute the magnetic-induced shear modulus of magnetorheological elastomers. Taking into account the influences of particles in the same chain and the particles in all adjacent chains, the traditional magnetic dipole model of the magnetorheological elastomers is modified. The influence of the ratio of the distance etween adjacent chains to the distance between adjacent particles in a chain on the magnetic induced shear odulus is quantitatively studied. When the ratio is large, the multi-chain model is compatible with the single chain model, but when the ratio is small, the difference of the two models is significant and can not be neglected. Making certain the size of the columns and the distance between adjacent columns, after constructing the computational model of BCT structures, the mechanical property of the magnetorheological elastomers composed of columnar structures is analyzed. Results show that, conventional point dipole model has overrated the magnetic-induced shear modulus of the magnetorheological elastomers. From the point of increasing the magnetic-induced shear modulus, when the particle volume fraction is small, the chain-like structure exhibits better result than the columnar structure, but when the particle volume fraction is large,the columnar structure will be better.展开更多
The effect of high magnetic field on the atomic interdiffusion in Ni-Cu system was studied using the Cu/Ni/Cu diffusion couples. During the atomic interdiffusion in Ni-Cu system, it was found that the interdiffusion c...The effect of high magnetic field on the atomic interdiffusion in Ni-Cu system was studied using the Cu/Ni/Cu diffusion couples. During the atomic interdiffusion in Ni-Cu system, it was found that the interdiffusion coefficients increased with the increase of molar fraction of Ni atoms in the interdiffusion zones when the couples were annealed with or without the magnetic field. It was noted that all corresponding interdiffusion coefficients under the magnetic field are smaller than those without the magnetic field. The results demonstrate that the magnetic field retards the atomic interdiffusion in Ni-Cu system. This retardation is achieved through reducing the frequency factors but not changing the interdiffusion activation energies.展开更多
The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sen...The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sensor was proposed. In this system, static and dynamic calibrations were conducted for infrared detectors and thermocouples, and then both temperature-time curves were obtained. Since the frequency response of infrared detector is superior to that of calibrat- ed thermocouple, the values measured by infrared detectors are taken as true values. Through dividing the values measured with thermocouples by those with infrared detectors, a normalized curve was obtained, based on which the time constant of thermocouple was measured. With this method, the experiments were carried out with NANMAC thermocouple to obtain its time constant. The results show that the method for measuring the time constant is feasible and the dynamic calibration of thermocouples can be achieved at microsecond and millisecond level. This research has a certain reference value for research and application of NANMAC thermocouple temperature sensor.展开更多
A high precision, high antijamming multipoint infrared telemetry system was developed to measure the piston temperature in internal combustion engine. The temperature at the measuring point is converted into correspon...A high precision, high antijamming multipoint infrared telemetry system was developed to measure the piston temperature in internal combustion engine. The temperature at the measuring point is converted into corresponding voltage signal by the thermo-couple first. Then after the V/F stage, the voltage signal is converted into the frequency signal to drive the infrared light-emitting diode to transmit infrared pulses. At the receiver end, a photosensitive audion receives the infrared pulses. After conversion, the voltage recorded by the receiver stands for the magnitude of temperature at the measuring point. Test results of the system indicate that the system is practical and the system can perform multipoint looping temperature measurements for the piston.展开更多
An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge...An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge. In this study, a comparison between the electromagnetic fields of an infinitesimal point charge and a dipole has been presented. First, the time-domain potential function of a point source in a 3D conductive medium is derived. Then the electric and magnetic fields in a 3D homogeneous lossless space are derived via the relation between the potential and field. The field differences between the infinitesimal point charge and the dipole in the step-off time, far-source, and near-source zones are analyzed, and the accuracy of the solutions from these sources is investigated. It is also shown that the field of the infinitesimal point charge in the near-source zone is different from that of the dipole, whereas the far-source zone fields of these two sources are identical. The comparison of real and simulated data shows that the infinitesimal point charge represents the real source better than the divole source.展开更多
Based on LabVlEW platform, a distributed dynamic storage testing system is designed for measuring transient high temperature signals of explosion field. Using a highpower semiconductor laser as heat source, a traceabl...Based on LabVlEW platform, a distributed dynamic storage testing system is designed for measuring transient high temperature signals of explosion field. Using a highpower semiconductor laser as heat source, a traceable dynamic calibration system is established to perform dynamic calibration of thermocouples. With quantumbehaved particle swam optimization (QP-SO) algorithm on MATLAB platform, a model of dynamic compensation filter is established. It is used by LabVIEW that calls MATLAB Script nodes or COM components to accomplish the mixed programming of LabVIEW and MATLAB, further to compensate the temperature values of the thermocouples dynamically. The experimental results show that the technique that combines temperature measurement system with LabVIEW platform is applied well in testing the explosion temperature of ther mobaric weaponry and makes the compensation values closer to the actual signals.展开更多
A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the s...A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the same laser could be used in the same system to carry on the static calibration of the radiation thermometer and the dynamic calibration of the temperature sensor to be checked. The frequency-response characteristics of high-speed radiation thermometer surpassed that of the temperature sensor, therefore it could be used as the reference value to calibrate the latter and let system error be cor- rected. Differences in the environment of the sensor installing and the error caused by the change of thermo-physical proper- ty could be avoided. Thus, the difficult problem of traceable dynamic calibration of temperature was solved. In experiment, to obtain the frequency characteristics of the thermocouple and the dynamic performance of the K type thermocouple, which could compensate the dynamic characteristics of the sensor, the sensor was dynamically corrected by using the method, and then the mathematical model was established.展开更多
[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin (CIT) was first conjugated with ve...[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin (CIT) was first conjugated with vector protein bovine serum albumin (BSA) and then identified by SDS-PAGE electrophoresis,and its coupling ratio was measured by UV absorption and mass spectrometry. [Result] The identification result showed that artificial antigen of CIT was successfully coupled,and the coupling ratio was 8.4 by UV absorption while 6.0 by mass spectrometry. [Conclusion] The comparison experiment showed that mass spectrometry could rapidly identify the artificial antigen and accurately detect its coupling ratio. This study provided basis for the preparation of CIT antigen as well as the establishment of an for enzyme-linked immunosorbent assay (ELISA) for citrinin determination.展开更多
A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperat...A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperature is measured by the tool/workpiece natural thermocouple, while the temperature distribution on the workpiece surface and that of interior are measured by some standard thermocouples prearranged at proper positions. The system can be used to measure cutting temperature in the machining with the rotary cutting tools, such as vertical drill and end milling cutter. It is practically used for the research on high-speed milling with hardened steel.展开更多
The large and small sized Cu(solid)/Al(liquid) couples were prepared to investigate the directional growth behavior of primary a(Al) phase during a concentration-gradient-controlled solidification process under ...The large and small sized Cu(solid)/Al(liquid) couples were prepared to investigate the directional growth behavior of primary a(Al) phase during a concentration-gradient-controlled solidification process under various static magnetic fields(SMFs).The results show that in the large couples,the α(Al) dendrites reveal a directional growth character whether without or with the SMF.However,the 12 T magnetic field induces regular growth,consistent deflection and the decrease of secondary arm spacing of the dendrites.In the small couples,the α(Al) dendrites still reveal a directional growth character to some extent with a SMF of ≤5 T.However,an 8.8 T SMF destroys the directional growth and induces severe random deflections of the dendrites.When the SMF increases to 12 T,the a(Al) dendrites become quite regular despite of the consistent deflection.The directional growth arises from the continuous long-range concentration gradient field built in the melt.The morphological modification is mainly related to the suppression of natural convections and the induction of thermoelectric magnetic convection by the SMF.展开更多
基金Projects(21073162,51131005)supported by the National Natural Science Foundation of ChinaProject(Y4100206)supported by the Science and Technology Bureau of Jiaxing Municipality and Zhejiang Provincial Natural Science Foundation of China
文摘The corrosion behaviors of copper and copper/titanium galvanic couple (GC) in seawater were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques in conjunction with scanning electron microscopy (SEM) method. The results show that the corrosion process of copper in seawater can be divided into two stages, in which corrosion resistance and SE show the same evolution trend of initial increase and subsequent decrease, while SG changes oppositely. However, the ensemble corrosion process of copper/titanium GC in seawater includes three stages, in which corrosion resistance and SE show the evolution features of initial decrease with a subsequently increase, and the final decrease again;while SG changes oppositely. The potential difference between copper and titanium in their galvanic couple can accelerate the initiation of pitting corrosion of copper, and both the minimum and maximum corrosion potentials of copper/titanium GC are much more positive than those of pure copper.
基金National Natural Science Foundation of China(30770310,30970435)Zhejiang Provincial Natural Science Foundation of China(Y307453)
文摘We recorded and described the calls and acoustic characteristics of the male tiger frog,Hoplobatrachus rugulosus,in an artificial pond during mating season.Spectral and temporal call parameters,along with call intensity were analyzed.Three harmonics were distinguishable from the spectrogram.Four patterns of dominant frequency were found in calls produced late at night,i.e,3 patterns in the first harmonic(located in 500 Hz section,700 Hz section,and 800 Hz section respectively) and 1 in the second harmonic(located in 1 800 Hz section).Call duration,call duty cycle,call intensity,and pulse rate were highly variable among different patterns of dominant frequency.These call properties could provide valuable evidence for further ecological study of this species.
基金Projects (50771092,21073162) supported by the National Natural Science Foundation of China
文摘Effects of reflowing temperature and time on the alloy layer of tinplate and its electrochemical behavior in 3.5%NaCl solution were investigated by electrochemical measurements and surface characterization.It is found that the amount of alloy layer increases with the increase of reflowing temperature and time.Then the corrosion potential of detinned tinplate shifts positively and the corrosion rate decreases.After being coupled with tin,the detinned tinplate acts as cathode and tin acts as anode initially.However,after being exposed for some time,the potential shifts of both detinned tinplate and tin reverse the polarity of the coupling system.The galvanic current density decreases with the increase of reflowing temperature and time.
基金Project (50771041) supported by the National Natural Science Foundation of ChinaProject (05-0350) supported by the New Century Excellent Talents in University, China
文摘To investigate the diffusion reaction between Ti/Al solid diffusion couple, Ti/Al alternate foils formed by hot pressing were annealed at 525, 550, 575 and 600 °C for time ranging from 1 to 40 h. The experimental results show that TiAl3 was the only observed phase at Ti/Al interface. The interface thermodynamics favored the preferential formation of TiAl3 in Ti/Al couple. The growth of TiAl3 layer occurred mainly towards Al foil side and exhibited a parabolic law. Using the interdiffusion coefficients calculated based on the contribution of grain boundary diffusion, the growth of TiAl3 was simulated numerically with the finite difference method, and the simulated results were in good agreement with the experimental ones.
文摘The mating calls of six forms belonging to four genera Megophrys,Oreloalax,Scutiger and Leptolalax were recorded in Wawu Mountain National Forest Park,Sichuan Province of China,using cassette tape recorder (Aiwa) and Sony tape with an external microphone.All recordings were analyzed with an IBM PC based 'SIGNAL' software analysis system (Engineering Design,USA).The range of analyzed frequency was set as 0-10 kHz.Acoustic analysis shows that the dominant frequency of L.oshanensis,M.minor,M.sp.,S.(S.)chintingensis,O.omeimontis,and O.schmidti is 4521.9,3456.4,2293.8,1076.5,1071.0 and 1849.4 Hz on average respectively;the note duration is 46.2,90.8,99.6,72.2,78.8 and 110.3 millisecond on average respectively;the note interval is 140.4,253.0,681.4,1517.7,461.3 and 619.5 millisecond on average respectively.One-Way ANOVA analysis indicates that there are significant differences among the analyzed six forms on the dominant frequency,the note duration,and the note interval (P<0.01).Multiple comparisons using Least-Significant Difference (LSD) show that the difference of the dominant frequency between S.(S.) chintingensis and O.omeimontis is not significant (P=0.917>0.05);on the note duration,only L.oshanensis is significantly different from M.minor,M.sp.,O.omeimontis and O.schmidti (P<0.01);on the note interval,L.oshanensis is not significantly different from M.minor,the same with M.sp.versus O.schmidti and O.omeimontis versus O.schmidti (P>0.05).Correlation analysis indicates that there are no significant correlation among the three acoustic characters of dominant frequency,note duration and note interval,and two environmental factors of the elevation and air temperature (P>0.05) except that the note interval is significantly linear correlated with the elevation (r=0.943,P=0.005<0.01).In the light of above,it is suggested that acoustic characteristics of calls are useful in distinguishing forms;the change of the note interval with the elevation may be a kind of strategy of reproduction.
文摘Based on the magnetic interaction energy, using derivative of the magnetic energy density, a model is proposed to compute the magnetic-induced shear modulus of magnetorheological elastomers. Taking into account the influences of particles in the same chain and the particles in all adjacent chains, the traditional magnetic dipole model of the magnetorheological elastomers is modified. The influence of the ratio of the distance etween adjacent chains to the distance between adjacent particles in a chain on the magnetic induced shear odulus is quantitatively studied. When the ratio is large, the multi-chain model is compatible with the single chain model, but when the ratio is small, the difference of the two models is significant and can not be neglected. Making certain the size of the columns and the distance between adjacent columns, after constructing the computational model of BCT structures, the mechanical property of the magnetorheological elastomers composed of columnar structures is analyzed. Results show that, conventional point dipole model has overrated the magnetic-induced shear modulus of the magnetorheological elastomers. From the point of increasing the magnetic-induced shear modulus, when the particle volume fraction is small, the chain-like structure exhibits better result than the columnar structure, but when the particle volume fraction is large,the columnar structure will be better.
基金Project(2011CB012803) supported by the National Basic Research Program of ChinaProject(NCET-10-0278) supported by Program for New Century Excellent Talents in University,China
文摘The effect of high magnetic field on the atomic interdiffusion in Ni-Cu system was studied using the Cu/Ni/Cu diffusion couples. During the atomic interdiffusion in Ni-Cu system, it was found that the interdiffusion coefficients increased with the increase of molar fraction of Ni atoms in the interdiffusion zones when the couples were annealed with or without the magnetic field. It was noted that all corresponding interdiffusion coefficients under the magnetic field are smaller than those without the magnetic field. The results demonstrate that the magnetic field retards the atomic interdiffusion in Ni-Cu system. This retardation is achieved through reducing the frequency factors but not changing the interdiffusion activation energies.
文摘The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sensor was proposed. In this system, static and dynamic calibrations were conducted for infrared detectors and thermocouples, and then both temperature-time curves were obtained. Since the frequency response of infrared detector is superior to that of calibrat- ed thermocouple, the values measured by infrared detectors are taken as true values. Through dividing the values measured with thermocouples by those with infrared detectors, a normalized curve was obtained, based on which the time constant of thermocouple was measured. With this method, the experiments were carried out with NANMAC thermocouple to obtain its time constant. The results show that the method for measuring the time constant is feasible and the dynamic calibration of thermocouples can be achieved at microsecond and millisecond level. This research has a certain reference value for research and application of NANMAC thermocouple temperature sensor.
文摘A high precision, high antijamming multipoint infrared telemetry system was developed to measure the piston temperature in internal combustion engine. The temperature at the measuring point is converted into corresponding voltage signal by the thermo-couple first. Then after the V/F stage, the voltage signal is converted into the frequency signal to drive the infrared light-emitting diode to transmit infrared pulses. At the receiver end, a photosensitive audion receives the infrared pulses. After conversion, the voltage recorded by the receiver stands for the magnitude of temperature at the measuring point. Test results of the system indicate that the system is practical and the system can perform multipoint looping temperature measurements for the piston.
基金supported by Chinese National Programs for Fundamental Research and Development(No.2012CB416605)the National Natural Science Foundation of China(No.41174090)Development Project of National Key Scientific Equipment(No.ZDYZ2012-1-05-04)
文摘An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge. In this study, a comparison between the electromagnetic fields of an infinitesimal point charge and a dipole has been presented. First, the time-domain potential function of a point source in a 3D conductive medium is derived. Then the electric and magnetic fields in a 3D homogeneous lossless space are derived via the relation between the potential and field. The field differences between the infinitesimal point charge and the dipole in the step-off time, far-source, and near-source zones are analyzed, and the accuracy of the solutions from these sources is investigated. It is also shown that the field of the infinitesimal point charge in the near-source zone is different from that of the dipole, whereas the far-source zone fields of these two sources are identical. The comparison of real and simulated data shows that the infinitesimal point charge represents the real source better than the divole source.
基金The 11th Postgraduate Technology Innovation Project of North University of China(No.20141147)
文摘Based on LabVlEW platform, a distributed dynamic storage testing system is designed for measuring transient high temperature signals of explosion field. Using a highpower semiconductor laser as heat source, a traceable dynamic calibration system is established to perform dynamic calibration of thermocouples. With quantumbehaved particle swam optimization (QP-SO) algorithm on MATLAB platform, a model of dynamic compensation filter is established. It is used by LabVIEW that calls MATLAB Script nodes or COM components to accomplish the mixed programming of LabVIEW and MATLAB, further to compensate the temperature values of the thermocouples dynamically. The experimental results show that the technique that combines temperature measurement system with LabVIEW platform is applied well in testing the explosion temperature of ther mobaric weaponry and makes the compensation values closer to the actual signals.
基金Research Project Supported by Shanxi Scholarship Council of China(No.2012-068)Taiyuan Science and Technology Agency(No.120247-20)Surface-temperature Sensor Dynamic Measurement and Calibration Technology Research of National Defense Fundamental Scientific Research
文摘A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the same laser could be used in the same system to carry on the static calibration of the radiation thermometer and the dynamic calibration of the temperature sensor to be checked. The frequency-response characteristics of high-speed radiation thermometer surpassed that of the temperature sensor, therefore it could be used as the reference value to calibrate the latter and let system error be cor- rected. Differences in the environment of the sensor installing and the error caused by the change of thermo-physical proper- ty could be avoided. Thus, the difficult problem of traceable dynamic calibration of temperature was solved. In experiment, to obtain the frequency characteristics of the thermocouple and the dynamic performance of the K type thermocouple, which could compensate the dynamic characteristics of the sensor, the sensor was dynamically corrected by using the method, and then the mathematical model was established.
基金Supported by National High Technology Research and Development Program of China (863 Program) (2007AA10Z426-1)~~
文摘[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin (CIT) was first conjugated with vector protein bovine serum albumin (BSA) and then identified by SDS-PAGE electrophoresis,and its coupling ratio was measured by UV absorption and mass spectrometry. [Result] The identification result showed that artificial antigen of CIT was successfully coupled,and the coupling ratio was 8.4 by UV absorption while 6.0 by mass spectrometry. [Conclusion] The comparison experiment showed that mass spectrometry could rapidly identify the artificial antigen and accurately detect its coupling ratio. This study provided basis for the preparation of CIT antigen as well as the establishment of an for enzyme-linked immunosorbent assay (ELISA) for citrinin determination.
文摘A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperature is measured by the tool/workpiece natural thermocouple, while the temperature distribution on the workpiece surface and that of interior are measured by some standard thermocouples prearranged at proper positions. The system can be used to measure cutting temperature in the machining with the rotary cutting tools, such as vertical drill and end milling cutter. It is practically used for the research on high-speed milling with hardened steel.
基金Projects(51201029,51071042,51374067)supported by the National Natural Science Foundation of ChinaProjects(N130409002,N130209001)supported by the Research Funds for the Central UniversitiesProject(2012M520637)supported by the China Postdoctoral Science Foundation
文摘The large and small sized Cu(solid)/Al(liquid) couples were prepared to investigate the directional growth behavior of primary a(Al) phase during a concentration-gradient-controlled solidification process under various static magnetic fields(SMFs).The results show that in the large couples,the α(Al) dendrites reveal a directional growth character whether without or with the SMF.However,the 12 T magnetic field induces regular growth,consistent deflection and the decrease of secondary arm spacing of the dendrites.In the small couples,the α(Al) dendrites still reveal a directional growth character to some extent with a SMF of ≤5 T.However,an 8.8 T SMF destroys the directional growth and induces severe random deflections of the dendrites.When the SMF increases to 12 T,the a(Al) dendrites become quite regular despite of the consistent deflection.The directional growth arises from the continuous long-range concentration gradient field built in the melt.The morphological modification is mainly related to the suppression of natural convections and the induction of thermoelectric magnetic convection by the SMF.