In the Ion Cyclotron Range of Frequency (ICRF) heating experiment, impedance matching is of great practical significance, because wide variations in antenna loading are observed within the discharge, in tokamaks opera...In the Ion Cyclotron Range of Frequency (ICRF) heating experiment, impedance matching is of great practical significance, because wide variations in antenna loading are observed within the discharge, in tokamaks operating in H-mode. A sudden decrease in antenna loading accompanying the L-mode to H-mode transition typically occurs on a timescale of a few milliseconds, as does the increase in loading at the H- to L-mode transition. Therefore, it is necessary to match dynamically in the transmission line between the generator output and the antenna input connections[1]. A new type of stub tuner being developed utilizes the difference in radio-frequency wavelengths between gas and liquid due to different relative dielectric constants. The impedance matching can be adjusted in realtime in an attempt to track the variations in the antenna loading. Since there are no mechanically moving parts in the short ends of stub, the change can be more convenient and safe, moreover, it can withstand higher voltage without breakdown. This system device will be applied in the HT-7 superconductor Tokamak ICRF experiment.展开更多
Ion cyclotron range of frequency（ICRF） heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the chan...Ion cyclotron range of frequency（ICRF） heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the change of plasma parameters in the ICRF heating process. To ensure the steady operation of the ICRF heating system in the EAST, fast ferrite tuner（FFT） has been carried out to achieve real-time impedance matching. For the requirements of the FFT impedance matching system, the magnet system of the ferrite tuner（FT） was designed by numerical simulations and experimental analysis, where the biasing magnetic circuit and alternating magnetic circuit were the key researched parts of the ferrite magnet. The integral design goal of the FT magnetic circuit is that DC bias magnetic field is 2000 Gs and alternating magnetic field is±400 Gs. In the FTT, E-type magnetic circuit was adopted. Ferrite material is Nd Fe B with a thickness of 30 mm by setting the working point of Nd Fe B, and the ampere turn of excitation coil is 25 through the theoretical calculation and simulation analysis. The coil inductance to generate alternating magnetic field is about 7 m H. Eddy-current effect has been analyzed, while the magnetic field distribution has been measured by a Hall probe in the medium plane of the biasing magnet. Finally, the test results show the good performance of the biasing magnet satisfying the design and operating requirements of the FFT.展开更多
In microwave circuit and aerial system, impedance matching is very important. Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have ...In microwave circuit and aerial system, impedance matching is very important. Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have already adopted liquid stub tuner to replace the conventional stub tuner. It is urgent to develop a control system of the liquid stub tuner. This paper mainly introduces the design and realization of the liquid stub tuner control system , and briefly introduces its three controlling functions: local control, remote control and computer control.展开更多
The paper studies photon-associated transmission through a quantum wire with a side-coupled stub tuner, to which an external microwave field applies, in terms of the approach developed by Cai. The inelastic scattering...The paper studies photon-associated transmission through a quantum wire with a side-coupled stub tuner, to which an external microwave field applies, in terms of the approach developed by Cai. The inelastic scattering of an incoming electron and the photon field lead to photon-electronic transmission though quantum wire. It is found that single photon absorbing (emitting) of the incoming electron in the stub can bring about antiresonant transmission in the quantum wire. The influence of the feedback mechanism from inelastic scattering process on elastic channel transmission is also examined. Total transmission coefficient as a function of photon energy exhibits non-periodic oscillation peaks. With the increasing of photon-electron coupling constant, the amplitude of these oscillation peaks enhances. Key words stub tuner - photon-associated transport - antiresonance PASC 2001 N72.25 Dc - 73.40.Ty - 73.23. Ad展开更多
This paper presents a novel electronic tuner with high power handling capability utilizing varactors based on the asymmetric bilateral coupled microstrip transmission line. Through varying the bias voltage of the vara...This paper presents a novel electronic tuner with high power handling capability utilizing varactors based on the asymmetric bilateral coupled microstrip transmission line. Through varying the bias voltage of the varactor at the Ultra High Frequency (UHF) band, the performance of the tuner is demonstrated according to simulated and measured results from several cases with the return loss (S11 ) below -20 dB and the insertion loss (S21 ) within ±0.5 dB. Compared with tuners using p and t network, electronic tuner of this paper shows superior frequency agility as well as wide impendence coverage. Advanced biasing structure has been developed to improve power handling for high power level applications. It is expected that the novel tuner would be part of intelligent Radio Frequency (RF) front-ends system and cognitive wireless system in the future.展开更多
The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating（ICRH） antennae with high power injection into plasmas.A sudden increase in the reflected radio frequency power due t...The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating（ICRH） antennae with high power injection into plasmas.A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors.This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions.The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution.Then,the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions.The method provides an alternative theoretical method,rather than measurements,to study triple liquid stub tuner impedance matching for ICRH,which may be beneficial for the design of ICRH systems on tokamaks.展开更多
随着数码打样技术的飞速发展、日趋成熟,直接制版(Computer To Plate)、直接印刷(Computer To Print),以及无胶片雕刻(Filmless Engraving)等技术的日益普及,印前工艺正在不断地迈向数字化,数码打样已经被越来越多的印刷企业所接受,印...随着数码打样技术的飞速发展、日趋成熟,直接制版(Computer To Plate)、直接印刷(Computer To Print),以及无胶片雕刻(Filmless Engraving)等技术的日益普及,印前工艺正在不断地迈向数字化,数码打样已经被越来越多的印刷企业所接受,印刷人也对它提出了更高的要求.但印刷企业如何更简单、更快捷地获得高质量的打样稿?如何更广泛地应用数码打样技术?如何更快捷地得到全面的技术支持与服务?展开更多
Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is...Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.展开更多
针对混合磁轴承PID控制器参数整定复杂的问题,分别采用PID Tuner和Controller System Tuner工具箱两种整定方法对PID参数进行整定,观察混合磁轴承系统的控制效果,并给定恒定外部干扰力对得到的PID参数进行验证,通过仿真结果证明了两种...针对混合磁轴承PID控制器参数整定复杂的问题,分别采用PID Tuner和Controller System Tuner工具箱两种整定方法对PID参数进行整定,观察混合磁轴承系统的控制效果,并给定恒定外部干扰力对得到的PID参数进行验证,通过仿真结果证明了两种参数整定方法的有效性和实用性。展开更多
Peking University is developing a 1.3 GHz superconducting accelerating section highpower THz free- electron laser for the China Academy of Engineering Physics （CAEP）. A compact fast/slow tuner has been developed by ...Peking University is developing a 1.3 GHz superconducting accelerating section highpower THz free- electron laser for the China Academy of Engineering Physics （CAEP）. A compact fast/slow tuner has been developed by the Institute of High Energy Physics （IHEP） for the accelerating section to control Lorentz detuning, compensate for beam loading effect, microphonics and liquid helium pressure fluctuations. The tuner design, warm test and cold test of the first prototype are presented, which has a guiding significance for the manufazture of the formal tuner and cryomodule assembly.展开更多
文摘In the Ion Cyclotron Range of Frequency (ICRF) heating experiment, impedance matching is of great practical significance, because wide variations in antenna loading are observed within the discharge, in tokamaks operating in H-mode. A sudden decrease in antenna loading accompanying the L-mode to H-mode transition typically occurs on a timescale of a few milliseconds, as does the increase in loading at the H- to L-mode transition. Therefore, it is necessary to match dynamically in the transmission line between the generator output and the antenna input connections[1]. A new type of stub tuner being developed utilizes the difference in radio-frequency wavelengths between gas and liquid due to different relative dielectric constants. The impedance matching can be adjusted in realtime in an attempt to track the variations in the antenna loading. Since there are no mechanically moving parts in the short ends of stub, the change can be more convenient and safe, moreover, it can withstand higher voltage without breakdown. This system device will be applied in the HT-7 superconductor Tokamak ICRF experiment.
基金supported by National Natural Science Foundation of China(Grant No.11575237)the National Magnetic Confinement Fusion Science Program(Grant No.2015GB101001)the International Scientific and Technological Cooperation Project of Anhui(Grant No.1704e1002207)
文摘Ion cyclotron range of frequency（ICRF） heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the change of plasma parameters in the ICRF heating process. To ensure the steady operation of the ICRF heating system in the EAST, fast ferrite tuner（FFT） has been carried out to achieve real-time impedance matching. For the requirements of the FFT impedance matching system, the magnet system of the ferrite tuner（FT） was designed by numerical simulations and experimental analysis, where the biasing magnetic circuit and alternating magnetic circuit were the key researched parts of the ferrite magnet. The integral design goal of the FT magnetic circuit is that DC bias magnetic field is 2000 Gs and alternating magnetic field is±400 Gs. In the FTT, E-type magnetic circuit was adopted. Ferrite material is Nd Fe B with a thickness of 30 mm by setting the working point of Nd Fe B, and the ampere turn of excitation coil is 25 through the theoretical calculation and simulation analysis. The coil inductance to generate alternating magnetic field is about 7 m H. Eddy-current effect has been analyzed, while the magnetic field distribution has been measured by a Hall probe in the medium plane of the biasing magnet. Finally, the test results show the good performance of the biasing magnet satisfying the design and operating requirements of the FFT.
文摘In microwave circuit and aerial system, impedance matching is very important. Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have already adopted liquid stub tuner to replace the conventional stub tuner. It is urgent to develop a control system of the liquid stub tuner. This paper mainly introduces the design and realization of the liquid stub tuner control system , and briefly introduces its three controlling functions: local control, remote control and computer control.
文摘The paper studies photon-associated transmission through a quantum wire with a side-coupled stub tuner, to which an external microwave field applies, in terms of the approach developed by Cai. The inelastic scattering of an incoming electron and the photon field lead to photon-electronic transmission though quantum wire. It is found that single photon absorbing (emitting) of the incoming electron in the stub can bring about antiresonant transmission in the quantum wire. The influence of the feedback mechanism from inelastic scattering process on elastic channel transmission is also examined. Total transmission coefficient as a function of photon energy exhibits non-periodic oscillation peaks. With the increasing of photon-electron coupling constant, the amplitude of these oscillation peaks enhances. Key words stub tuner - photon-associated transport - antiresonance PASC 2001 N72.25 Dc - 73.40.Ty - 73.23. Ad
基金Supported by the National Science and Technology Major Project of China (No. 2010ZX03007-003-04)Ningbo University - Agilent Joint Laboratory, the National Natural Science Foundation of China (No. 61171040)+5 种基金the Key Project of International Cooperation of the Provincial Science Technology Major Projects of Zhejiang (No. 2010C14007)the Provincial Natural Science Foundation of Zhejiang (No. Y1101270)the Natural Science Foundation of Ningbo (No. 2011A610188)the Scientific Research Foundation of Graduate School of Ningbo University (No. G12JA019)Scientific Research Fund of Zhejiang Provincial Education Department (No. Y201224247)Research Foundation of Ningbo University (No. XKL11D2064)
文摘This paper presents a novel electronic tuner with high power handling capability utilizing varactors based on the asymmetric bilateral coupled microstrip transmission line. Through varying the bias voltage of the varactor at the Ultra High Frequency (UHF) band, the performance of the tuner is demonstrated according to simulated and measured results from several cases with the return loss (S11 ) below -20 dB and the insertion loss (S21 ) within ±0.5 dB. Compared with tuners using p and t network, electronic tuner of this paper shows superior frequency agility as well as wide impendence coverage. Advanced biasing structure has been developed to improve power handling for high power level applications. It is expected that the novel tuner would be part of intelligent Radio Frequency (RF) front-ends system and cognitive wireless system in the future.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2014GB108002,2013GB107001)National Natural Science Foundation of China(Nos.11205086,11205053,11375085,and 11405082)+1 种基金the Construct Program of Fusion and Plasma Physics Innovation Team in Hunan Province,China(No.NHXTD03)the Natural Science Foundation of Hunan Province,China(No.2015JJ4044)
文摘The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating（ICRH） antennae with high power injection into plasmas.A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors.This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions.The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution.Then,the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions.The method provides an alternative theoretical method,rather than measurements,to study triple liquid stub tuner impedance matching for ICRH,which may be beneficial for the design of ICRH systems on tokamaks.
文摘随着数码打样技术的飞速发展、日趋成熟,直接制版(Computer To Plate)、直接印刷(Computer To Print),以及无胶片雕刻(Filmless Engraving)等技术的日益普及,印前工艺正在不断地迈向数字化,数码打样已经被越来越多的印刷企业所接受,印刷人也对它提出了更高的要求.但印刷企业如何更简单、更快捷地获得高质量的打样稿?如何更广泛地应用数码打样技术?如何更快捷地得到全面的技术支持与服务?
文摘Eight 500 MHz cavities are applied in the storage ring of the Shanghai Synchrotron Radiation Factility (SSRF). In order to tune the cavities for different changing parameters and operation modes, the control system is es- sential for operations. The tuning is achieved by synchronizing the drive signal and the cavity probe signal. The error signal defined as their subtraction is amplified and used to drive a stepping motor, which in turn moves a metallic plunger in or out of the cavity by programmable logic controller (PLC). The tune speed is set to be 1kHz/s.
基金Supported by the 500 MHz superconducting cavity electromechanical tuning system(Y190KFEOHD)NSAF(11176003)National Major Scientific Instrument and Equipment Development projects(2011YQ130018)
文摘Peking University is developing a 1.3 GHz superconducting accelerating section highpower THz free- electron laser for the China Academy of Engineering Physics （CAEP）. A compact fast/slow tuner has been developed by the Institute of High Energy Physics （IHEP） for the accelerating section to control Lorentz detuning, compensate for beam loading effect, microphonics and liquid helium pressure fluctuations. The tuner design, warm test and cold test of the first prototype are presented, which has a guiding significance for the manufazture of the formal tuner and cryomodule assembly.
