The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resisti...The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resistivity is always not equal to the real resistivity.To determine the real resistivity,a linear relationship of the measured resistivity,contact resistance and the real resistivity was established.Then experiments for six specimens with varying graphite contents were designed and performed to validate the formulation.Results of experiments demonstrate that the slope of the line represents contact resistance,and the intercept indicates the real resistivity.The effects of graphite content on contact resistance and real resistivity are also revealed.Finally,results show that the influence of contact resistance on accuracy of resisitvity measurement becomes more serious if graphite content is beyond 3%.Hence,it is the time to choose this novel methodology to determine the real resistivity of asphalt concrete by taking account of contact resistance.展开更多
The DRM （dynamic contact resistance measurement） in high voltage circuit breakers is a manner of evaluating the internal ageing condition of the chamber. DRM is similar to static contact resistance measurement testi...The DRM （dynamic contact resistance measurement） in high voltage circuit breakers is a manner of evaluating the internal ageing condition of the chamber. DRM is similar to static contact resistance measurement testing, but instead of measuring a single value when the breaker contacts are closed （static value）, the ohmic resistance is measured at various contact positions, from the beginning of the contact opening until a complete separation of the contacts. The relationship between the contact resistances of the new circuit breaker and the ageing circuit breaker in operation provides subsidy for the evaluation of both the main and arcing contact conditions. This research aims to analyze the correlation between the various levels of degradation of the contacts and the configuration of the DRM curve. This work considers curve samples from new acceleration tests. breaker chamber contacts and different levels of degradation by展开更多
In the frame of the ZeuS-Ill project, a model study was started on evaluation the area-specific resistances （ASRs） of various layers being used in SOFC stacks. It is well known that stack performance not only depend...In the frame of the ZeuS-Ill project, a model study was started on evaluation the area-specific resistances （ASRs） of various layers being used in SOFC stacks. It is well known that stack performance not only depends on cell resistance but also on the electrical conductivity of the various applied contact and protective layers. Various layers have been tested under simulated SOFC conditions, and results have shown that the lowest ASR value, about 3 mΩ.cm2, was obtained for an LSM （2） contact layer. A significantly higher resistance was found for the combined contact and protective layer LCC10-Mn3O4, being around 37 mΩ.cm2 Related to the various tests, the total ASR of an F-design stack, developed by Forschungszentrum Jiilich, under ideal conditions can be estimated. In this case the ASR value was calculated as the sum of that of the LCC10-Mn3O4 layer and the formed oxide scale due to oxidation of Crofer22APU. Contacting resistance at the anode side was considered negligible. When differences in the ASR values occurred when compared with that from current-voltage measurements performed with real SOFC stacks, this can be explained by the limited contact area between interconnect and cathode. These results can be used to model the influence of various applied layers and different geometric contact areas on the overall ASR as determined from performance measurements with SOFC stacks.展开更多
Microcontact measurement is employed to locally investigate the electric and dielectric properties of individual grains and grain boundaries in CaCu3Ti4O12 ceramic. The measurements give more detail of the impedance s...Microcontact measurement is employed to locally investigate the electric and dielectric properties of individual grains and grain boundaries in CaCu3Ti4O12 ceramic. The measurements give more detail of the impedance spectroscopy, capacitance, and I-V characteristics of the microstructure, and will help with further understanding of the mechanism of the electric and dielectric properties of CaCu3Ti4O12 ceramics.展开更多
基金Project(51178348)supported by the National Natural Science Foundation of China
文摘The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resistivity is always not equal to the real resistivity.To determine the real resistivity,a linear relationship of the measured resistivity,contact resistance and the real resistivity was established.Then experiments for six specimens with varying graphite contents were designed and performed to validate the formulation.Results of experiments demonstrate that the slope of the line represents contact resistance,and the intercept indicates the real resistivity.The effects of graphite content on contact resistance and real resistivity are also revealed.Finally,results show that the influence of contact resistance on accuracy of resisitvity measurement becomes more serious if graphite content is beyond 3%.Hence,it is the time to choose this novel methodology to determine the real resistivity of asphalt concrete by taking account of contact resistance.
文摘The DRM （dynamic contact resistance measurement） in high voltage circuit breakers is a manner of evaluating the internal ageing condition of the chamber. DRM is similar to static contact resistance measurement testing, but instead of measuring a single value when the breaker contacts are closed （static value）, the ohmic resistance is measured at various contact positions, from the beginning of the contact opening until a complete separation of the contacts. The relationship between the contact resistances of the new circuit breaker and the ageing circuit breaker in operation provides subsidy for the evaluation of both the main and arcing contact conditions. This research aims to analyze the correlation between the various levels of degradation of the contacts and the configuration of the DRM curve. This work considers curve samples from new acceleration tests. breaker chamber contacts and different levels of degradation by
文摘In the frame of the ZeuS-Ill project, a model study was started on evaluation the area-specific resistances （ASRs） of various layers being used in SOFC stacks. It is well known that stack performance not only depends on cell resistance but also on the electrical conductivity of the various applied contact and protective layers. Various layers have been tested under simulated SOFC conditions, and results have shown that the lowest ASR value, about 3 mΩ.cm2, was obtained for an LSM （2） contact layer. A significantly higher resistance was found for the combined contact and protective layer LCC10-Mn3O4, being around 37 mΩ.cm2 Related to the various tests, the total ASR of an F-design stack, developed by Forschungszentrum Jiilich, under ideal conditions can be estimated. In this case the ASR value was calculated as the sum of that of the LCC10-Mn3O4 layer and the formed oxide scale due to oxidation of Crofer22APU. Contacting resistance at the anode side was considered negligible. When differences in the ASR values occurred when compared with that from current-voltage measurements performed with real SOFC stacks, this can be explained by the limited contact area between interconnect and cathode. These results can be used to model the influence of various applied layers and different geometric contact areas on the overall ASR as determined from performance measurements with SOFC stacks.
基金supported by the National Nature Science Foundation of China (Grant Nos.50425721,50677029 and 50737001)
文摘Microcontact measurement is employed to locally investigate the electric and dielectric properties of individual grains and grain boundaries in CaCu3Ti4O12 ceramic. The measurements give more detail of the impedance spectroscopy, capacitance, and I-V characteristics of the microstructure, and will help with further understanding of the mechanism of the electric and dielectric properties of CaCu3Ti4O12 ceramics.
