为研究电动汽车无线充电系统,解决电动汽车有线充电时的不安全、不便利问题,采用磁耦合谐振式无线电能传输技术,从改进传输线圈结构出发,在传输线圈外侧增加导磁体,将磁通尽可能束缚在两传输线圈之间,减小向外界的泄漏,缩短磁通在空气...为研究电动汽车无线充电系统,解决电动汽车有线充电时的不安全、不便利问题,采用磁耦合谐振式无线电能传输技术,从改进传输线圈结构出发,在传输线圈外侧增加导磁体,将磁通尽可能束缚在两传输线圈之间,减小向外界的泄漏,缩短磁通在空气中的磁路长度,从而有效增强无线电能传输系统的耦合程度,大大增加传输功率,提高低频条件下的传输距离和效率。设计了具有频率自动跟踪控制的12 k W/70 k Hz高效磁耦合谐振式电动汽车无线充电系统,并进行实验研究,得到一系列传输线圈距离和负载阻抗、传输功率及传输效率之间关系的实验数据。特别地,实验结果表明在传输距离0.3 m、输入功率12.6 k W时,谐振频率为72.6 k Hz,传输效率达到94.33%。展开更多
Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage...Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage of using GDC for transcatheter CAF closure is more controllable,therefore much safer when compared to other coils.This report is about our experience in transcatheter closure of CAF using fibered GDC in our hospital.Methods ＆ Results From 2002 to 2007,there were 10 patients with CAFs （age range：28 to 56 year-old,7 males） who underwent transcatheter CAF closure.There were a total of 19 CAFs which originated from right coronary （n =5）,left circumflex （n =3）,left anterior descending artery （n =10） and left main trunk （n =1）.Median number of coil deployment for each fistula was 3 （range：1 to 6）.The pulmonary artery was the most common site of the distal communication of CAFs （n =14）,followed by right atrium （n =3）,left atrium （n =1） and left ventricle （n =1）.Immediate coronary angiography after GDC deployment revealed no residual shunt in 12 （63.2％） CAFs,significant reduction of the flow in 5 （26.3％）,while 2 （10.5％） could not be closed due to small size.Nine （90％） patients underwent a repeated angiography within 3 to 8 months.Among 12 CAFs that were occluded immediately post-deployment,there were 2 CAFs with insignificant residual flow.Among 6 CAFs with significantly decreased flow immediately post-deployment,2 were occluded totally in the follow-up angiography.In total,12 （70.5％） CAFs were occluded completely and 5 （29.5％） CAFs still had insignificant residual flow,which did not need any additional coil deployment.During a mean follow up of 4.3 ± 0.7 year,all patients remained symptom and complication free.Conclusions The fibered GDC is a safe and effective method for percutaneous closure of the CAFs.展开更多
This paper presents an experimental study on the evaluation of thermal response of a spiral coil type GHE （ground heat exchanger）. This GHE was installed on partially saturated landfill ground that was composed of s...This paper presents an experimental study on the evaluation of thermal response of a spiral coil type GHE （ground heat exchanger）. This GHE was installed on partially saturated landfill ground that was composed of silt and clay in the runway area of Incheon International airport. TRT （thermal response test） was conducted for more than 65 hours under continuous operation conditions. Ground thermal conductivity was derived based on line source theory, which has usually been found to be appropriate for line type GHEs such as U, W and 2U types. A reasonable method to derive ground thermal conductivity using the infinite line source theory for a spiral coil type GHE was introduced. Ground thermal conductivity from the TRT using spiral coil type GHE was compared with those from the analytical equivalent model of ground thermal conductivity.展开更多
During the aluminum electrolytic roasting process,each component of the electrobath of aluminum performs unsteadily when the electrolytic bath is in the pre-roasting stage. It is important to monitor the currents of t...During the aluminum electrolytic roasting process,each component of the electrobath of aluminum performs unsteadily when the electrolytic bath is in the pre-roasting stage. It is important to monitor the currents of the anodes and the cathodes of the aluminum electrobath at regular intervals. Both practice and investigation indicate that Rogowski coil can be adopted to measure heavy direct current of the anodes and the cathodes of the aluminum electrobath. The paper not only introduces the typical application of the Rogowski coil to inspect the state of aluminum electrobath in the roasting process, but also analyzes the principles of the coil sensor including its dynamic properties and some important measurement results respectively. The optimal parameters of the coil can be simulated by means of an advanced simulation tool: simulink tools based on MATLAB soft environment. Based on the gathered current data, an even-current coefficient has been introduced, and the current curve can be drawn. Since they are applied in AL-Electrolyzing, it is possible to distinguish the anode of which the current is not evenly distributed, and to take adjusting measures over a period of time to ensure that the current is evenly distributed.展开更多
Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric cu...Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric current is required to impose the magnetic field on the ship hull, which in turn means that the deperming coil needs to be wound on ship hull when the coil is composed of conventional conductive materials, such as copper. We considered a few HTS （high temperature superconducting） coil systems to deperm naval ships because we expect the shorter deperming time and lower manual workload for ship deperming operation, compared conventional conductor coil systems. We have in the past presented a solution using a fiat two-coil system arranged on seabed with tightly bound HTS conductor by analytical calculation of magnetic field on the conductor. By considering present and already developed technologies, a conductor with cylindrically wound on the core arranged as fiat multi-turn coils on seabed was designed using analytical methods.展开更多
The optimal design method for an open Magnetic Resonance Imaging （MRI） superconducting magnet with an active shielding configuration is proposed. Firstly, three pairs of current rings are employed as seed coils. By ...The optimal design method for an open Magnetic Resonance Imaging （MRI） superconducting magnet with an active shielding configuration is proposed. Firstly, three pairs of current rings are employed as seed coils. By optimizing the homogeneity of Diameter Sphere Voltnne （DSV）, the positions and currents of the seed coils will be obtained. Secondly, according to the positions and currents of the seed coils, the current density of superconducting wires is determined, and then the original sections for the coils can be achieved. An optimization for the homogeneity based on the constrained nonlincar optimization method is employed to determine the coils with good homogeneity. Thirdly, the magnetic field generated by previous coils is set as the background field, then add two coils with reverse current, and optimize the stray field line of 5 Gauss in a certain scope. Finally, a further optimization for the homogeneity is used to get Final coils. This method can also be used in the design of other axisynmaetfic superconducting MRI magnets.展开更多
This paper presents the methodology and results of modelling of Earth magnetic field disturbances induced by ferromagnetic objects. The modeling was carried out using the finite elements calculations, and the results ...This paper presents the methodology and results of modelling of Earth magnetic field disturbances induced by ferromagnetic objects. The modeling was carried out using the finite elements calculations, and the results were compared with the measurements. The special test stand, consisting of magnetovision scanner and Helmholtz coils, has been used. The measurement system is able to measure the distribution of planar magnetic induction vectors, and to differentiate the sources of measured disturbances.展开更多
The tectono-magmatism in eastern China is a hotspot for the researches, and many hypotheses of that were discussed. There is a middle crust with solid, low velocity and high conductivity in eastern China, which is imp...The tectono-magmatism in eastern China is a hotspot for the researches, and many hypotheses of that were discussed. There is a middle crust with solid, low velocity and high conductivity in eastern China, which is impossible to form"convection magmatic layer". The subduction and compression of oceanic plate induced to the lateral pressure for the eastern China lithosphere in the condition of increasing pressure and decreasing temperature, it is also impossible to form an extensively melting magma layer. In South China, the granitic zone migrates from west to east, their evolution cannot be explained by plate subduction. The original magmatic reservoirs are controlled by main faults and spheres, which occurred the tectonic detachment and formed in the process of decreasing pressure and increasing temperature. The magma only originates in very small part of lithosphere. The tectono-magmatism and tectonic detachment of eastern China lithosphere during the Jurassic and the Cretaceous are concentrate mainly near the intersections between the regional faults and middle crust or the Moho discontinuity, and then magma intrudes or erupts along faults. The tectono-magmatism of Cenozoic originates near the intersections between the regional high-angle normal faults and the bottom of lithosphere. Obviously, the different penetration depth of faults induces a different kind of magmatism.展开更多
Significant efforts have been devoted to enhancing the sensitivity and working range of flexible pressure sensors to improve the precise measurement of subtle variations in pressure over a wide detection spectrum. How...Significant efforts have been devoted to enhancing the sensitivity and working range of flexible pressure sensors to improve the precise measurement of subtle variations in pressure over a wide detection spectrum. However,achieving sensitivities exceeding 1000 kPa^(-1) while maintaining a pressure working range over 100 kPa is still challenging because of the limited intrinsic properties of soft matrix materials. Here, we report a magnetic field-induced porous elastomer with micropillar arrays(MPAs) as sensing materials and a well-patterned nickel fabric as an electrode. The developed sensor exhibits an ultrahigh sensitivity of 10,268 kPa^(-1)(0.6–170 kPa) with a minimum detection pressure of 0.25 Pa and a fast response time of 3 ms because of the unique structure of the MPAs and the textured morphology of the electrode. The porous elastomer provides an extended working range of up to 500 kPa with long-time durability. The sophisticated sensor system coupled with an integrated wireless recharging system comprising a flexible supercapacitor and inductive coils for transmission achieves excellent performance. Thus, a diverse range of practical applications requiring a low-to-high pressure range sensing can be developed. Our strategy, which combines a microstructured high-performance sensor device with a wireless recharging system, provides a basis for creating next-generation flexible electronics.展开更多
文摘为研究电动汽车无线充电系统,解决电动汽车有线充电时的不安全、不便利问题,采用磁耦合谐振式无线电能传输技术,从改进传输线圈结构出发,在传输线圈外侧增加导磁体,将磁通尽可能束缚在两传输线圈之间,减小向外界的泄漏,缩短磁通在空气中的磁路长度,从而有效增强无线电能传输系统的耦合程度,大大增加传输功率,提高低频条件下的传输距离和效率。设计了具有频率自动跟踪控制的12 k W/70 k Hz高效磁耦合谐振式电动汽车无线充电系统,并进行实验研究,得到一系列传输线圈距离和负载阻抗、传输功率及传输效率之间关系的实验数据。特别地,实验结果表明在传输距离0.3 m、输入功率12.6 k W时,谐振频率为72.6 k Hz,传输效率达到94.33%。
文摘Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage of using GDC for transcatheter CAF closure is more controllable,therefore much safer when compared to other coils.This report is about our experience in transcatheter closure of CAF using fibered GDC in our hospital.Methods ＆ Results From 2002 to 2007,there were 10 patients with CAFs （age range：28 to 56 year-old,7 males） who underwent transcatheter CAF closure.There were a total of 19 CAFs which originated from right coronary （n =5）,left circumflex （n =3）,left anterior descending artery （n =10） and left main trunk （n =1）.Median number of coil deployment for each fistula was 3 （range：1 to 6）.The pulmonary artery was the most common site of the distal communication of CAFs （n =14）,followed by right atrium （n =3）,left atrium （n =1） and left ventricle （n =1）.Immediate coronary angiography after GDC deployment revealed no residual shunt in 12 （63.2％） CAFs,significant reduction of the flow in 5 （26.3％）,while 2 （10.5％） could not be closed due to small size.Nine （90％） patients underwent a repeated angiography within 3 to 8 months.Among 12 CAFs that were occluded immediately post-deployment,there were 2 CAFs with insignificant residual flow.Among 6 CAFs with significantly decreased flow immediately post-deployment,2 were occluded totally in the follow-up angiography.In total,12 （70.5％） CAFs were occluded completely and 5 （29.5％） CAFs still had insignificant residual flow,which did not need any additional coil deployment.During a mean follow up of 4.3 ± 0.7 year,all patients remained symptom and complication free.Conclusions The fibered GDC is a safe and effective method for percutaneous closure of the CAFs.
文摘This paper presents an experimental study on the evaluation of thermal response of a spiral coil type GHE （ground heat exchanger）. This GHE was installed on partially saturated landfill ground that was composed of silt and clay in the runway area of Incheon International airport. TRT （thermal response test） was conducted for more than 65 hours under continuous operation conditions. Ground thermal conductivity was derived based on line source theory, which has usually been found to be appropriate for line type GHEs such as U, W and 2U types. A reasonable method to derive ground thermal conductivity using the infinite line source theory for a spiral coil type GHE was introduced. Ground thermal conductivity from the TRT using spiral coil type GHE was compared with those from the analytical equivalent model of ground thermal conductivity.
文摘During the aluminum electrolytic roasting process,each component of the electrobath of aluminum performs unsteadily when the electrolytic bath is in the pre-roasting stage. It is important to monitor the currents of the anodes and the cathodes of the aluminum electrobath at regular intervals. Both practice and investigation indicate that Rogowski coil can be adopted to measure heavy direct current of the anodes and the cathodes of the aluminum electrobath. The paper not only introduces the typical application of the Rogowski coil to inspect the state of aluminum electrobath in the roasting process, but also analyzes the principles of the coil sensor including its dynamic properties and some important measurement results respectively. The optimal parameters of the coil can be simulated by means of an advanced simulation tool: simulink tools based on MATLAB soft environment. Based on the gathered current data, an even-current coefficient has been introduced, and the current curve can be drawn. Since they are applied in AL-Electrolyzing, it is possible to distinguish the anode of which the current is not evenly distributed, and to take adjusting measures over a period of time to ensure that the current is evenly distributed.
文摘Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric current is required to impose the magnetic field on the ship hull, which in turn means that the deperming coil needs to be wound on ship hull when the coil is composed of conventional conductive materials, such as copper. We considered a few HTS （high temperature superconducting） coil systems to deperm naval ships because we expect the shorter deperming time and lower manual workload for ship deperming operation, compared conventional conductor coil systems. We have in the past presented a solution using a fiat two-coil system arranged on seabed with tightly bound HTS conductor by analytical calculation of magnetic field on the conductor. By considering present and already developed technologies, a conductor with cylindrically wound on the core arranged as fiat multi-turn coils on seabed was designed using analytical methods.
基金supported by the National Natural Science Foundation of China(No.50577063)
文摘The optimal design method for an open Magnetic Resonance Imaging （MRI） superconducting magnet with an active shielding configuration is proposed. Firstly, three pairs of current rings are employed as seed coils. By optimizing the homogeneity of Diameter Sphere Voltnne （DSV）, the positions and currents of the seed coils will be obtained. Secondly, according to the positions and currents of the seed coils, the current density of superconducting wires is determined, and then the original sections for the coils can be achieved. An optimization for the homogeneity based on the constrained nonlincar optimization method is employed to determine the coils with good homogeneity. Thirdly, the magnetic field generated by previous coils is set as the background field, then add two coils with reverse current, and optimize the stray field line of 5 Gauss in a certain scope. Finally, a further optimization for the homogeneity is used to get Final coils. This method can also be used in the design of other axisynmaetfic superconducting MRI magnets.
文摘This paper presents the methodology and results of modelling of Earth magnetic field disturbances induced by ferromagnetic objects. The modeling was carried out using the finite elements calculations, and the results were compared with the measurements. The special test stand, consisting of magnetovision scanner and Helmholtz coils, has been used. The measurement system is able to measure the distribution of planar magnetic induction vectors, and to differentiate the sources of measured disturbances.
文摘The tectono-magmatism in eastern China is a hotspot for the researches, and many hypotheses of that were discussed. There is a middle crust with solid, low velocity and high conductivity in eastern China, which is impossible to form"convection magmatic layer". The subduction and compression of oceanic plate induced to the lateral pressure for the eastern China lithosphere in the condition of increasing pressure and decreasing temperature, it is also impossible to form an extensively melting magma layer. In South China, the granitic zone migrates from west to east, their evolution cannot be explained by plate subduction. The original magmatic reservoirs are controlled by main faults and spheres, which occurred the tectonic detachment and formed in the process of decreasing pressure and increasing temperature. The magma only originates in very small part of lithosphere. The tectono-magmatism and tectonic detachment of eastern China lithosphere during the Jurassic and the Cretaceous are concentrate mainly near the intersections between the regional faults and middle crust or the Moho discontinuity, and then magma intrudes or erupts along faults. The tectono-magmatism of Cenozoic originates near the intersections between the regional high-angle normal faults and the bottom of lithosphere. Obviously, the different penetration depth of faults induces a different kind of magmatism.
基金supported by the National Natural Science Foundation of China (61904141)the Funding of the Natural Science Foundation of Shaanxi Province (2020JQ-295)+2 种基金China Postdoctoral Science Foundation (2020M673340)the Key Research and Development Program of Shaanxi (2020GY-252)the National Key Laboratory of Science and Technology on Vacuum Technology and Physics (HTKJ2019KL510007)。
文摘Significant efforts have been devoted to enhancing the sensitivity and working range of flexible pressure sensors to improve the precise measurement of subtle variations in pressure over a wide detection spectrum. However,achieving sensitivities exceeding 1000 kPa^(-1) while maintaining a pressure working range over 100 kPa is still challenging because of the limited intrinsic properties of soft matrix materials. Here, we report a magnetic field-induced porous elastomer with micropillar arrays(MPAs) as sensing materials and a well-patterned nickel fabric as an electrode. The developed sensor exhibits an ultrahigh sensitivity of 10,268 kPa^(-1)(0.6–170 kPa) with a minimum detection pressure of 0.25 Pa and a fast response time of 3 ms because of the unique structure of the MPAs and the textured morphology of the electrode. The porous elastomer provides an extended working range of up to 500 kPa with long-time durability. The sophisticated sensor system coupled with an integrated wireless recharging system comprising a flexible supercapacitor and inductive coils for transmission achieves excellent performance. Thus, a diverse range of practical applications requiring a low-to-high pressure range sensing can be developed. Our strategy, which combines a microstructured high-performance sensor device with a wireless recharging system, provides a basis for creating next-generation flexible electronics.
