Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508584
M. Tian, X. Wang, W. Zhao, Y. Yang, J. Diao, X. Ma
Permanent magnet coupler (PMC) acts as a magnetic transmission device, the motivation and torque are transmitted through the interaction between the conductor rotor (CR) and permanent magnet rotor (PMR), the mechanical contact between the motor and load is eliminated. And for the effective suppression of the vibration, high reliability and efficient operation, it has been applied in electric power, petrochemical industry, pumps, blowers, water treatment and other fields [1]–[3]. Many structures of the PMCs had been designed, considering the rotational couplers, configurations as radial and axial magnetic flux represent two possible solutions [4]. For the typical axial flux coupler (i.e., disk type) and radial flux coupler (i.e., cylindrical type), the produced torque was controlled by adjusting the length of air gap or the coupling area between the CR and PMR [5]. However, the magnetic field utilization is lower for disk type, and additional mechanical devices are also needed to adjust the axial relative position between the CR and PMR for both types, the reliability is reduced and the space volume is increased. In [6], a flux adjustable PMC with a movable stator ring, whose slip speed can be adjusted by shifting the movable stator ring along the axial direction, was proposed, and the complicated mechanical devices can be avoided. In this paper, a novel flux adjustable PMC with a double-layer PMR is presented. The magnetic flux is adjusted by circumferentially controlling the relative position of the PMR’s two layers, the axial movement is replaced.
{"title":"Analysis on a Novel Flux Adjustable Permanent Magnet Eddy Current Coupler with a Double-layer Permanent Magnet Rotor.","authors":"M. Tian, X. Wang, W. Zhao, Y. Yang, J. Diao, X. Ma","doi":"10.1109/INTMAG.2018.8508584","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508584","url":null,"abstract":"Permanent magnet coupler (PMC) acts as a magnetic transmission device, the motivation and torque are transmitted through the interaction between the conductor rotor (CR) and permanent magnet rotor (PMR), the mechanical contact between the motor and load is eliminated. And for the effective suppression of the vibration, high reliability and efficient operation, it has been applied in electric power, petrochemical industry, pumps, blowers, water treatment and other fields [1]–[3]. Many structures of the PMCs had been designed, considering the rotational couplers, configurations as radial and axial magnetic flux represent two possible solutions [4]. For the typical axial flux coupler (i.e., disk type) and radial flux coupler (i.e., cylindrical type), the produced torque was controlled by adjusting the length of air gap or the coupling area between the CR and PMR [5]. However, the magnetic field utilization is lower for disk type, and additional mechanical devices are also needed to adjust the axial relative position between the CR and PMR for both types, the reliability is reduced and the space volume is increased. In [6], a flux adjustable PMC with a movable stator ring, whose slip speed can be adjusted by shifting the movable stator ring along the axial direction, was proposed, and the complicated mechanical devices can be avoided. In this paper, a novel flux adjustable PMC with a double-layer PMR is presented. The magnetic flux is adjusted by circumferentially controlling the relative position of the PMR’s two layers, the axial movement is replaced.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"19 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78062842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508683
H. Zhou, J. Yuan, L. Wei, P. Gan, F. Chen, Y. Zhong, C. Tian, B. Chen, Y. Gao, K. Muramatsu
In order to protect high voltage direct current(HVDC) system from destructive damage caused by large DC fault current, a HVDC system saturable core type fault current limiter(DCSFCL) is proposed previously. However, through principle investigation and simulation analysis of DCSFCL, coil inductance of DCSFCL do not have a large changing rate (CR) when a fault occurs, so clipping performance of it will not be quite satisfying. In order to increase CR and improve clipping performance of original DCSFCL, further improvements need to be carried out. In this digest, a modified three limb structure of DCSFCL(TSFCL) is proposed and equivalent magnetic and electric circuit are analyzed. Simulations carried out on ANSYS shows that clipping performance is improved by a large scale.
{"title":"A Novel Three Limb Topology of a Saturated Core Fault Current Limiter in HVDC System","authors":"H. Zhou, J. Yuan, L. Wei, P. Gan, F. Chen, Y. Zhong, C. Tian, B. Chen, Y. Gao, K. Muramatsu","doi":"10.1109/INTMAG.2018.8508683","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508683","url":null,"abstract":"In order to protect high voltage direct current(HVDC) system from destructive damage caused by large DC fault current, a HVDC system saturable core type fault current limiter(DCSFCL) is proposed previously. However, through principle investigation and simulation analysis of DCSFCL, coil inductance of DCSFCL do not have a large changing rate (CR) when a fault occurs, so clipping performance of it will not be quite satisfying. In order to increase CR and improve clipping performance of original DCSFCL, further improvements need to be carried out. In this digest, a modified three limb structure of DCSFCL(TSFCL) is proposed and equivalent magnetic and electric circuit are analyzed. Simulations carried out on ANSYS shows that clipping performance is improved by a large scale.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"47 21 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78080123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508198
W. Busyatras, N. Jongsawat, L. Myint, C. Warisarn
Inter-track interference (ITI) cancelation is one of the considerable challenges for high areal density (AD) magnetic recording such as in bit-patterned media recording (BPMR) systems. In literature, the two-dimensional (2D) modulation codes have been proposed to cancel the ITI effect [1, 2] which can efficiently improve the overall system performance, e.g., a rate-5/6 2D modulation code [2]. Although the rate-5/6 modulation code ensures that the readback signal of the center track will not be corrupted by severe ITI; however, both the upper and lower tracks can still be interfered by their sidetracks. To improve this shortcoming; therefore, we propose the bit-flipping technique that performs together with the rate5/6 2D modulation code. Here, the relationship between the data encoding condition and soft-information obtained from the soft output Viterbi algorithm (SOVA) detector is utilized to be a criterion for flipping the ambiguous data bits. Simulation results indicate that the proposed system is better than the conventional coded system under with/without media noise and track mis-registration.
{"title":"A Bit-Flipping Technique Based on 2D Modulation Constraint in BPMR Systems.","authors":"W. Busyatras, N. Jongsawat, L. Myint, C. Warisarn","doi":"10.1109/INTMAG.2018.8508198","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508198","url":null,"abstract":"Inter-track interference (ITI) cancelation is one of the considerable challenges for high areal density (AD) magnetic recording such as in bit-patterned media recording (BPMR) systems. In literature, the two-dimensional (2D) modulation codes have been proposed to cancel the ITI effect [1, 2] which can efficiently improve the overall system performance, e.g., a rate-5/6 2D modulation code [2]. Although the rate-5/6 modulation code ensures that the readback signal of the center track will not be corrupted by severe ITI; however, both the upper and lower tracks can still be interfered by their sidetracks. To improve this shortcoming; therefore, we propose the bit-flipping technique that performs together with the rate5/6 2D modulation code. Here, the relationship between the data encoding condition and soft-information obtained from the soft output Viterbi algorithm (SOVA) detector is utilized to be a criterion for flipping the ambiguous data bits. Simulation results indicate that the proposed system is better than the conventional coded system under with/without media noise and track mis-registration.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"87 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78125381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508474
B. Reese, C. R. Sullivan, U. Wegst
Abstract
摘要
{"title":"Freeze-Cast Magnetic Composites for High Frequency Power Conversion.","authors":"B. Reese, C. R. Sullivan, U. Wegst","doi":"10.1109/INTMAG.2018.8508474","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508474","url":null,"abstract":"Abstract","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"7 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78254732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508113
Y. Xiao, H. Wang, T. Huang, Y. Zou, Z. Zeng, K. Wang, C. Xie
All-optical magnetic switching (AOS) observed on some materials provides a potential recording option due to its ultra-short recording-time [1]. In most studies, it is attributed to inverse Faraday effect (IFE) that circularly polarized laser will induce an opto-magnetic field [2, 3] or magnetic circular dichroism (MCD) that one magnetization orientation will absorb more energy than another [4, 5]. L10-FePt is a promising candidate for high density magnetic recording due to its high perpendicular anisotropy [6] whose magnetization is fixed out of plane either up or down. However, the mechanism about AOS on FePt is still under debate. In our research, we show that it benefits from both IFE and MCD. Taking both the thermal effect and the induced opto-magnetic field into account, we calculate the switching probability of L10-FePt nanoparticles for a single laser pulse with different opto-magnetic fields by atomistic level simulation [7], as shown in Fig. 1(a-d). We consider the effect of multi-shot pulses by an accumulative model, assuming that the switching probability after each shot is identical. Fig. 1(f) shows the normalized net magnetisation variation with different MCD ratios when the opto-magnetic field induced by left circularly laser pulse (δ−) is −0.1 Tesla. Obviously, when the MCD ratio is 2%, the final magnetisation is in agreement with the experiment result of Lambert et al. that the magnetization induced by circularly polarized laser is ~10 to 20% of saturation magnetization [8]. This MCD ratio is reasonable for FePt [5, 9]. Fig. 2(a-c) show the final magnetisation over multiple linearly (L), left (σ−) and right (σ+) circularly laser pulses respectively with different initial magnetization states, which verify that AOS is helicity-dependent but independent of the initial state. Fig. 2(d) shows the magnetisation variation over laser fluence with different opto-magnetic fields. Applying an external magnetic field 0.03 Tesla when the opto-magnetic field is −0.1 Tesla, the corresponding effective magnetic field is −0.07 Tesla. In this case, the net magnetisation roughly equals to 0 at a wide laser fluence range, which is qualitatively consistent with the results of Lambert et al. that a 700 Oe field could eliminate the all-optical switching. In addition, when the opto-magnetic fields are ±0.4 Tesla, there will be a deterministic switching that the final magnetization is greater 90% of the saturation magnetization. Taking the opto-magnetic field −0.4T as example, the net magnetisation after multiple laser pulses is shown in Fig. 2(e), and the fastest deterministic switching occurs at 34 mJ/cm2 after 34 left circularly laser pulses. Although our simulation is simplified, these results demonstrate the possibility of reaching deterministic all-optical magnetic recording by optimizing the parameters presented above.
{"title":"Hybrid characteristic of multi-shot circularly polarized laser pulses for magnetization switching process in L10-FePt nanoparticles.","authors":"Y. Xiao, H. Wang, T. Huang, Y. Zou, Z. Zeng, K. Wang, C. Xie","doi":"10.1109/INTMAG.2018.8508113","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508113","url":null,"abstract":"All-optical magnetic switching (AOS) observed on some materials provides a potential recording option due to its ultra-short recording-time [1]. In most studies, it is attributed to inverse Faraday effect (IFE) that circularly polarized laser will induce an opto-magnetic field [2, 3] or magnetic circular dichroism (MCD) that one magnetization orientation will absorb more energy than another [4, 5]. L10-FePt is a promising candidate for high density magnetic recording due to its high perpendicular anisotropy [6] whose magnetization is fixed out of plane either up or down. However, the mechanism about AOS on FePt is still under debate. In our research, we show that it benefits from both IFE and MCD. Taking both the thermal effect and the induced opto-magnetic field into account, we calculate the switching probability of L10-FePt nanoparticles for a single laser pulse with different opto-magnetic fields by atomistic level simulation [7], as shown in Fig. 1(a-d). We consider the effect of multi-shot pulses by an accumulative model, assuming that the switching probability after each shot is identical. Fig. 1(f) shows the normalized net magnetisation variation with different MCD ratios when the opto-magnetic field induced by left circularly laser pulse (δ−) is −0.1 Tesla. Obviously, when the MCD ratio is 2%, the final magnetisation is in agreement with the experiment result of Lambert et al. that the magnetization induced by circularly polarized laser is ~10 to 20% of saturation magnetization [8]. This MCD ratio is reasonable for FePt [5, 9]. Fig. 2(a-c) show the final magnetisation over multiple linearly (L), left (σ−) and right (σ+) circularly laser pulses respectively with different initial magnetization states, which verify that AOS is helicity-dependent but independent of the initial state. Fig. 2(d) shows the magnetisation variation over laser fluence with different opto-magnetic fields. Applying an external magnetic field 0.03 Tesla when the opto-magnetic field is −0.1 Tesla, the corresponding effective magnetic field is −0.07 Tesla. In this case, the net magnetisation roughly equals to 0 at a wide laser fluence range, which is qualitatively consistent with the results of Lambert et al. that a 700 Oe field could eliminate the all-optical switching. In addition, when the opto-magnetic fields are ±0.4 Tesla, there will be a deterministic switching that the final magnetization is greater 90% of the saturation magnetization. Taking the opto-magnetic field −0.4T as example, the net magnetisation after multiple laser pulses is shown in Fig. 2(e), and the fastest deterministic switching occurs at 34 mJ/cm2 after 34 left circularly laser pulses. Although our simulation is simplified, these results demonstrate the possibility of reaching deterministic all-optical magnetic recording by optimizing the parameters presented above.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"7 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78355746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508743
Y. Liu, J. Ou, M. Schiefer, M. Doppelbauer
This paper compares the rotor losses and the thermal fields of a surface-mounted PM synchronous ultrahigh-speed motor with different sleeve types. Currently, fiber sleeves and metal sleeves are commonly used. Both types of sleeves have high yield strength. However, they have disadvantages either on rotor losses or on heat dissipation. It is well-known that the fiber sleeve can avoid high eddy current losses, but the thermal conductivity is low. Compared with the fiber sleeve, the metal sleeve has higher thermal conductivity. However, its electrical conductivity is also high which causes high eddy current losses. Hence, this paper compares the two sleeves to provide a reference for the machine designers.
{"title":"Comparison of Sleeve Types for Ultra-High-Speed Surface-Mounted PM Motors.","authors":"Y. Liu, J. Ou, M. Schiefer, M. Doppelbauer","doi":"10.1109/INTMAG.2018.8508743","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508743","url":null,"abstract":"This paper compares the rotor losses and the thermal fields of a surface-mounted PM synchronous ultrahigh-speed motor with different sleeve types. Currently, fiber sleeves and metal sleeves are commonly used. Both types of sleeves have high yield strength. However, they have disadvantages either on rotor losses or on heat dissipation. It is well-known that the fiber sleeve can avoid high eddy current losses, but the thermal conductivity is low. Compared with the fiber sleeve, the metal sleeve has higher thermal conductivity. However, its electrical conductivity is also high which causes high eddy current losses. Hence, this paper compares the two sleeves to provide a reference for the machine designers.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"444 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75108567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508224
Yanfang Hu, Wen Ding
This paper mainly presents the static inductance and flux linkage characteristics of a switched reluctance motor (SRM) with 12/10 poles when it respectively works as a six-phase motor and a three-phase motor. Two excitation types, single phase excitation (SPE) and double phase excitation (DPE), are separately applied to the two operation modes. The comparison between self and mutual inductances under different excitation types show that the proportion of the mutual inductance between two adjacent phases in its self inductance is much larger than that of non-adjacent phases for six-phase mode, and it is also larger than that of three-phase mode. Finally, the simulations are experimentally proved by using an indirect flux linkage measurement method. A good consistency between the simulated and measured results is shown.
{"title":"Study on Static Magnetic Characteristics of a Switched Reluctance Motor with 12/10 Poles under Different Operation Modes","authors":"Yanfang Hu, Wen Ding","doi":"10.1109/INTMAG.2018.8508224","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508224","url":null,"abstract":"This paper mainly presents the static inductance and flux linkage characteristics of a switched reluctance motor (SRM) with 12/10 poles when it respectively works as a six-phase motor and a three-phase motor. Two excitation types, single phase excitation (SPE) and double phase excitation (DPE), are separately applied to the two operation modes. The comparison between self and mutual inductances under different excitation types show that the proportion of the mutual inductance between two adjacent phases in its self inductance is much larger than that of non-adjacent phases for six-phase mode, and it is also larger than that of three-phase mode. Finally, the simulations are experimentally proved by using an indirect flux linkage measurement method. A good consistency between the simulated and measured results is shown.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"43 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78108276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508377
C. Madhusudan
Improved electrochemical and sensing properties of CeO 2 nanoparticles were obtained by co-doping with $mathrm {Y}^{3+}$ and Dy $^{3+}$ to attain Ce $^{4+} /$Ce $^{3+}$ valence states with the associated generation of oxygen vacancies. Ce $_{0.8} mathrm {Y}_{0.20}x$ Dy $_{x} mathrm {O}_{2- {delta }}( mathrm {x}=0.00,0.10,0.20)$ nanoparticles were synthesized by sol-gel auto combustion method, calcined at $800 ^{0}mathrm {C}$ for 2hr in air and innovatively sintered by means of microwave heating at $1300 ^{0}mathrm {C}$ for 30min. The phase identification, structural and morphological analysis were characterized by XRD, SEM, TEM and Raman Spectroscopy. The ionic conductivity was analyzed by Impedance Spectroscopy. The gas sensing properties were tested at room temperature. Intense $mathrm {F}_{2g}$ Raman band at 460cm $^{-1}$ from Raman spectra in concurrence with XRD diffractograms revealed that the investigated samples exhibited the cubic fluorite structure of CeO 2. SEM and TEM results ascertained the nano level microstructure. The shift in XRD peak ascertained that the dopants were dissolved into the host lattice, and the subsequent creation of oxygen vacancies, due to the change in valence state from Ce $^{4+}$ to Ce $^{3+}$. The generation of oxygen vacancies and the resultant enhancement in ionic conductivity was validated by the results of Raman specta and Impedance analysis. Because of special microstructure, the obtained sample showed excellent gas sensing properties towards the ethanol at room temperature. High response, fast response-recovery time and excellent selectivity to ethanol gas, suggested the promising gas sensing application of the sample Ce 0.8Y0.10 Dy $_{0.10} mathrm {O}_{2-delta }$.
{"title":"Modification of Ce valence states by Y/Dy co-doping of CeO2 nanoparticles for effective Electrical and Sensing properties.","authors":"C. Madhusudan","doi":"10.1109/INTMAG.2018.8508377","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508377","url":null,"abstract":"Improved electrochemical and sensing properties of CeO 2 nanoparticles were obtained by co-doping with $mathrm {Y}^{3+}$ and Dy $^{3+}$ to attain Ce $^{4+} /$Ce $^{3+}$ valence states with the associated generation of oxygen vacancies. Ce $_{0.8} mathrm {Y}_{0.20}x$ Dy $_{x} mathrm {O}_{2- {delta }}( mathrm {x}=0.00,0.10,0.20)$ nanoparticles were synthesized by sol-gel auto combustion method, calcined at $800 ^{0}mathrm {C}$ for 2hr in air and innovatively sintered by means of microwave heating at $1300 ^{0}mathrm {C}$ for 30min. The phase identification, structural and morphological analysis were characterized by XRD, SEM, TEM and Raman Spectroscopy. The ionic conductivity was analyzed by Impedance Spectroscopy. The gas sensing properties were tested at room temperature. Intense $mathrm {F}_{2g}$ Raman band at 460cm $^{-1}$ from Raman spectra in concurrence with XRD diffractograms revealed that the investigated samples exhibited the cubic fluorite structure of CeO 2. SEM and TEM results ascertained the nano level microstructure. The shift in XRD peak ascertained that the dopants were dissolved into the host lattice, and the subsequent creation of oxygen vacancies, due to the change in valence state from Ce $^{4+}$ to Ce $^{3+}$. The generation of oxygen vacancies and the resultant enhancement in ionic conductivity was validated by the results of Raman specta and Impedance analysis. Because of special microstructure, the obtained sample showed excellent gas sensing properties towards the ethanol at room temperature. High response, fast response-recovery time and excellent selectivity to ethanol gas, suggested the promising gas sensing application of the sample Ce 0.8Y0.10 Dy $_{0.10} mathrm {O}_{2-delta }$.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"48 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75718335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508147
B. Guo, Y. Huang
In this paper, a general analytical model is proposed to consider the thickness of backplate of axial flux permanent magnet (AFPM) machine with Halbach arrays. Firstly, the machine is represented in a 3-region model, viz, rotor iron, PM and airgap region, then, the slotless flux density is developed by Maxwell's equations. Second, the Schwarz-Christoffel (SC) mapping technique is introduced to consider the slot effect. Moreover, a simple magnetic equivalent circuit is introduced to calculated the magnetic permeability of rotor iron. The results show that the analytical predictions agree well with the finite element (FE) results, also, the model is verified via the performance of experimental results. The main contribution of this model is that the rotor iron part is taken into consideration, which is more accuracy.
{"title":"Analytical Model for Axial Flux PM Machines with Halbach Arrays: Taking into Account of Rotor Iron.","authors":"B. Guo, Y. Huang","doi":"10.1109/INTMAG.2018.8508147","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508147","url":null,"abstract":"In this paper, a general analytical model is proposed to consider the thickness of backplate of axial flux permanent magnet (AFPM) machine with Halbach arrays. Firstly, the machine is represented in a 3-region model, viz, rotor iron, PM and airgap region, then, the slotless flux density is developed by Maxwell's equations. Second, the Schwarz-Christoffel (SC) mapping technique is introduced to consider the slot effect. Moreover, a simple magnetic equivalent circuit is introduced to calculated the magnetic permeability of rotor iron. The results show that the analytical predictions agree well with the finite element (FE) results, also, the model is verified via the performance of experimental results. The main contribution of this model is that the rotor iron part is taken into consideration, which is more accuracy.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"119 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75778618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-01DOI: 10.1109/INTMAG.2018.8508123
K. Zhang, Y. Zhang, Z. Zhang, Z. Zheng, J. Nan, G. Wang, Y. Wang, W. Yun, W. Zhao
Magnetoresistance (MR) effect is at the heart of modern information storage, which represents the electrical resistance change ratio of materials or devices under the application of external magnetic field. In order to realize large MR value, lots of promising materials and structures were proposed. Extraordinary MR (EMR) [1], [2] in some non-magnetic semiconductors has gained much attention owing to the large MR magnitude and linear magnetic field dependence, which can be ascribed to inhomogeneity of carrier density or mobility. Recently, large MR value was realized by exquisitely coupling the magnetic response of materials and the nonlinear transport effect of diode [3], [4]. However, these devices could not satisfy the requirement of high sensitivity at low magnetic field and small work current simultaneously. Here, we utilized the negative MR and large resistivity of ZnCoO magnetic semiconductor films to realize high magnetic-field sensitivity with small work current at room temperature. In our experiments, ZnCoO magnetic semiconductor films of 60 nm were cut into a stripe with 7 mm in length and 2 mm in width. As shown in Fig. 1(a), linear voltage-current (V-I) curves and about -13% MR values were observed. Here, MR is always defined as MR $=( mathrm {V}_{H}- mathrm {V}_{0})/ mathrm {V}_{H,}$ where $mathrm {V}_{H}$ and V0 are the voltage detected with and without applied magnetic field respectively. Then a Zener diode was connected between electrode 1 and 4 to fabricate a diode assisted ZnCoO device (DAZD). Fig. 1(b) shows the V-I curves and MR value of the DAZD with 9.1V Zener diode under different magnetic fields. A sharp increase in voltage by several orders was observed at critical transition current $mathrm {I}_{C}=0.375$ mA under 0T, which is directly related with the Zener Diode. When the applied current is smaller than 0.375 mA, the voltage dropped on the diode is smaller than the critical voltage $(mathrm {U}_{C})$ of Zener diode and the diode could be considered as open circuit, which results in a small measured voltage because of the voltage attenuation with the increase of distance. When the voltage dropped on the diode is larger than $mathrm {U}_{C}$, the diode can be considered as short circuit and electrode 4 and 1 turn into short-connected, which results in a sudden increase in the detected voltage. As shown in Fig. 1(b), the MR value of the DAZD is high up to -1539% at 0.1T, -3958% at 0.4T, -5359% at 1T and -6850% MR at 6T with small work current, which is a higher sensitivity in low magnetic field compared with the Si, Ge, GaAs nonmagnetic semiconductor. As shown in Fig. 1(c), the MR value and the shape of MR curve could be tuned by the applied current. For $mathrm {I}=0.380$ mA and $mathrm {I}=0.428$ mA, the MR value is almost the same $(sim -850$%), but the former one is much higher than the later one in magnetic field sensitivity and the shape of the MR curves changes from sharp to obtuse. Generally, the MR value of DAZD
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