针对一般磁楔电抗器无法快速改变电抗值的问题,提出了一种新型可调的齿形磁楔式电力电抗器.与一般磁楔电抗器相比,这种电抗器可以通过成倍地减小调节距离来成倍地提高调节速度.以一台设计制作的220 V、8 k Var齿形磁楔电抗器样机为研究...针对一般磁楔电抗器无法快速改变电抗值的问题,提出了一种新型可调的齿形磁楔式电力电抗器.与一般磁楔电抗器相比,这种电抗器可以通过成倍地减小调节距离来成倍地提高调节速度.以一台设计制作的220 V、8 k Var齿形磁楔电抗器样机为研究对象,应用ANSYS有限元分析软件,建立了该电抗器的三维磁场模型,计算磁楔在两个极限位置时的电抗器磁场分布,应用ANSYS的LMATRIX宏命令计算该电抗器的电感调节特性.研究结果表明:该电抗器与一般磁楔电抗器相比,不仅可以提供相同的电感调节特性,而且具有数倍的电感调节速度.展开更多
Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Cou⁃pled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tun⁃able funct...Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Cou⁃pled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tun⁃able functions based on the transition between amorphous and crystalline states.However,the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices.Here,this paper introduces a novel approach-a multi-functional metadevice achieved through the two-level control of the encoding phasechange metaatoms.Utilizing the phase-change material Ge_(2)Sb_(2)Se_(4)Te1(GSST)and high refractive-index liquid di⁃iodomethane(CH_(2)I_(2)),this paper showcases precise control over electromagnetic wave manipulation.The GSST state governs the tunable function,switching it ON and OFF,while the presence of liquid in the hole dictates the deflection angle when the tunable function is active.Importantly,our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum.The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice,enabling dynamic switching of encoding bit levels.This two-level tun⁃able metadevice,rooted in phase-change materials,presents a promising avenue for the dynamic control of func⁃tions.展开更多
A permanent magnet microwave ion source with adjustable magnetic field is developed at China Institute of Atomic Energy.The magnetic field in the region of ionization chamber is generated by permanent magnets.Outside ...A permanent magnet microwave ion source with adjustable magnetic field is developed at China Institute of Atomic Energy.The magnetic field in the region of ionization chamber is generated by permanent magnets.Outside the magnet,an iron yoke is installed to adjust the magnetic field,and the yoke can be adjusted easily by hands.With adjustable magnetic field,the ion source can be tuned into the optimized operational condition.From an aperture of 3mm in diameter,17mA hydrogen beam has been extracted.展开更多
Dispersible FePt intermetallic nanopartides （NPs） with tunable composition were synthesized by thermal annealing of MgO coated A1-FePt （or A1-FePt-Fe304） NPs followed by an acid treatment to remove MgO. High-tem- ...Dispersible FePt intermetallic nanopartides （NPs） with tunable composition were synthesized by thermal annealing of MgO coated A1-FePt （or A1-FePt-Fe304） NPs followed by an acid treatment to remove MgO. High-tem- perature annealing facilitates the conversion of FePt from disordered alloy to ordered intermetaUics. Under the protec- tion of MgO, the diffusion of Fe and Pt atoms was limited, making it possible for the atom reconstruction in the lattice to give discrete FePt intermetaUic NPs after a facile acid etching process. FePt intermetallic NPs formed face-centered cubic and face-centered tetragonal structures with their magnetic properties tuned by composition. The saturation magnetiza- tion was adjusted from 8 to 52 emu g^-1 by increasing the Fe concentration, while the coercivity reached a max/mum of 33 kOe when Fe concentration was 44%. After surface mod- ifications by hydrophilic or hydrophobic molecules containing thiol groups, FePt intermetallic NPs could be dissolved into water or hydrocarbon solvents. The hydrophilic L10-FePt in- termetallic NPs were applied as contrast agents for magnetic resonance imaging, showing a high transverse relaxivity of 328.6 mmo1^-1 L s^-l, which indicated the great potential of FePt intermetallic NPs as molecular probes for cancer diagnosis.展开更多
Design and application of tunable phononic crystals(PnCs)are attracting increasing interest due to their promising capabilities to manipulate acoustic and elastic waves effectively.This paper investigates topology opt...Design and application of tunable phononic crystals(PnCs)are attracting increasing interest due to their promising capabilities to manipulate acoustic and elastic waves effectively.This paper investigates topology optimization of the magnetorheological(MR)materials including PnCs for opening the tunable and wide bandgaps.Therein,the bandgap tunability of the PnCs is achieved by shear modulus variation of MR materials under a continuously changing applied magnetic field.The pseudo elemental densities representing the bi-material distribution inside the PnC unit cell are taken as design variables and interpolated with an artificial MR penalization model.An aggregated bandgap index for enveloping the extreme values ofbandgap width and tunable range of the MR included smart PnCs is proposed as the objective function.In this context,the sensitivity analysis scheme is derived,and the optimization problem is solved with the gradient-based mathematical programming method.The effectiveness of the proposed optimization method is demonstrated by numerical examples,where the optimized solutions present tunable and stably wide bandgap characteristics under different magnetic fields.The tunable optimized PnCs based device that can provide a wider tunable bandgap range is also explored.展开更多
The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into differ...The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.展开更多
We demonstrate the fabrication of magnetically assembled one-dimensional chain-like photonic nanostructures with significantly high photonic stability. The key lies in the use of agarose hydrogel to prevent coagulatio...We demonstrate the fabrication of magnetically assembled one-dimensional chain-like photonic nanostructures with significantly high photonic stability. The key lies in the use of agarose hydrogel to prevent coagulation of the magnetic assemblies. When exposed to an external magnetic field, negatively charged Fe3O4@SiO2 particles can effectively assemble in the hydrogel matrix into one- dimensional chains with internal periodicity and display a fast, fully reversible, and tunable photonic response to the changes in the external field. The steric hindrance and the hydrogen bonding from the agarose network effectively limit the migration of the Fe304@SiO2 particles and their chain-like assemblies. As a result, the system shows remarkable stability in photonic response under external magnetic fields of large gradients, something which has previously been a challenge. The ability to stabilize the magnetic particle assemblies over a long period represents a major stride toward practical applications of such field- responsive photonic materials.展开更多
Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple metho...Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni3Si2O5（OH）4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA.h.g-1 after 21 cycles at a rate of 20 mA.g-1, Furthermore, after the nanotubes were calcined （600 ℃, 4 h） or reduced （180℃ 10 h）, the corresponding discharge capacities increased to 277.2 mA.h.g-1 and 308.5 mA.h.g-1, respectively.展开更多
文摘针对一般磁楔电抗器无法快速改变电抗值的问题,提出了一种新型可调的齿形磁楔式电力电抗器.与一般磁楔电抗器相比,这种电抗器可以通过成倍地减小调节距离来成倍地提高调节速度.以一台设计制作的220 V、8 k Var齿形磁楔电抗器样机为研究对象,应用ANSYS有限元分析软件,建立了该电抗器的三维磁场模型,计算磁楔在两个极限位置时的电抗器磁场分布,应用ANSYS的LMATRIX宏命令计算该电抗器的电感调节特性.研究结果表明:该电抗器与一般磁楔电抗器相比,不仅可以提供相同的电感调节特性,而且具有数倍的电感调节速度.
基金Supported by the Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB0580000,XDB43010200)National Natural Science Foundation of China(62222514,62350073,U2341226,61991440)+5 种基金National Key Research and Development Program of China(2023YFA1406900)Shanghai Science and Technology Committee(23ZR1482000,22JC1402900,22ZR1472700)Natural Science Foundation of Zheji‐ang Province(LR22F050004)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Youth Innovation Promotion Association(Y2021070)and International Partnership Program(112GJHZ2022002FN)of Chinese Academy of SciencesShanghai Human Resources and Social Security Bureau(2022670),and China Postdoctoral Science Foundation(2023T160661,2022TQ0353 and 2022M713261).
文摘Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Cou⁃pled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tun⁃able functions based on the transition between amorphous and crystalline states.However,the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices.Here,this paper introduces a novel approach-a multi-functional metadevice achieved through the two-level control of the encoding phasechange metaatoms.Utilizing the phase-change material Ge_(2)Sb_(2)Se_(4)Te1(GSST)and high refractive-index liquid di⁃iodomethane(CH_(2)I_(2)),this paper showcases precise control over electromagnetic wave manipulation.The GSST state governs the tunable function,switching it ON and OFF,while the presence of liquid in the hole dictates the deflection angle when the tunable function is active.Importantly,our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum.The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice,enabling dynamic switching of encoding bit levels.This two-level tun⁃able metadevice,rooted in phase-change materials,presents a promising avenue for the dynamic control of func⁃tions.
文摘A permanent magnet microwave ion source with adjustable magnetic field is developed at China Institute of Atomic Energy.The magnetic field in the region of ionization chamber is generated by permanent magnets.Outside the magnet,an iron yoke is installed to adjust the magnetic field,and the yoke can be adjusted easily by hands.With adjustable magnetic field,the ion source can be tuned into the optimized operational condition.From an aperture of 3mm in diameter,17mA hydrogen beam has been extracted.
基金supported by the National Natural Science Foundation of China (51602285, 51590882, 51631001, 51672010 and 81421004)the National Key R&D Program of China (2017YFA0206301)the Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and technology, Chinese Academy of Sciences (NSKF201607)
文摘Dispersible FePt intermetallic nanopartides （NPs） with tunable composition were synthesized by thermal annealing of MgO coated A1-FePt （or A1-FePt-Fe304） NPs followed by an acid treatment to remove MgO. High-tem- perature annealing facilitates the conversion of FePt from disordered alloy to ordered intermetaUics. Under the protec- tion of MgO, the diffusion of Fe and Pt atoms was limited, making it possible for the atom reconstruction in the lattice to give discrete FePt intermetaUic NPs after a facile acid etching process. FePt intermetallic NPs formed face-centered cubic and face-centered tetragonal structures with their magnetic properties tuned by composition. The saturation magnetiza- tion was adjusted from 8 to 52 emu g^-1 by increasing the Fe concentration, while the coercivity reached a max/mum of 33 kOe when Fe concentration was 44%. After surface mod- ifications by hydrophilic or hydrophobic molecules containing thiol groups, FePt intermetallic NPs could be dissolved into water or hydrocarbon solvents. The hydrophilic L10-FePt in- termetallic NPs were applied as contrast agents for magnetic resonance imaging, showing a high transverse relaxivity of 328.6 mmo1^-1 L s^-l, which indicated the great potential of FePt intermetallic NPs as molecular probes for cancer diagnosis.
基金supported by the National Natural Science Foundation of China(Grant No.12102079).
文摘Design and application of tunable phononic crystals(PnCs)are attracting increasing interest due to their promising capabilities to manipulate acoustic and elastic waves effectively.This paper investigates topology optimization of the magnetorheological(MR)materials including PnCs for opening the tunable and wide bandgaps.Therein,the bandgap tunability of the PnCs is achieved by shear modulus variation of MR materials under a continuously changing applied magnetic field.The pseudo elemental densities representing the bi-material distribution inside the PnC unit cell are taken as design variables and interpolated with an artificial MR penalization model.An aggregated bandgap index for enveloping the extreme values ofbandgap width and tunable range of the MR included smart PnCs is proposed as the objective function.In this context,the sensitivity analysis scheme is derived,and the optimization problem is solved with the gradient-based mathematical programming method.The effectiveness of the proposed optimization method is demonstrated by numerical examples,where the optimized solutions present tunable and stably wide bandgap characteristics under different magnetic fields.The tunable optimized PnCs based device that can provide a wider tunable bandgap range is also explored.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11074293,51021061 and 50831006)
文摘The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.
文摘We demonstrate the fabrication of magnetically assembled one-dimensional chain-like photonic nanostructures with significantly high photonic stability. The key lies in the use of agarose hydrogel to prevent coagulation of the magnetic assemblies. When exposed to an external magnetic field, negatively charged Fe3O4@SiO2 particles can effectively assemble in the hydrogel matrix into one- dimensional chains with internal periodicity and display a fast, fully reversible, and tunable photonic response to the changes in the external field. The steric hindrance and the hydrogen bonding from the agarose network effectively limit the migration of the Fe304@SiO2 particles and their chain-like assemblies. As a result, the system shows remarkable stability in photonic response under external magnetic fields of large gradients, something which has previously been a challenge. The ability to stabilize the magnetic particle assemblies over a long period represents a major stride toward practical applications of such field- responsive photonic materials.
基金This work was supported by the Natural Science Foundation of China （No. 20725102）, the Fok Ying Tung Education Foundation （No. 111012）, and the State Key Project of Fundamental Research for Nanoscience and Nanotechnology （Nos. 2011CB932402, 2007CB310501, and 2011CB935704）.
文摘Highly crystalline and thermally stable pure multi-walled Ni3Si2O5（OH）4 nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200-210 ℃ using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni3Si2O5（OH）4 nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA.h.g-1 after 21 cycles at a rate of 20 mA.g-1, Furthermore, after the nanotubes were calcined （600 ℃, 4 h） or reduced （180℃ 10 h）, the corresponding discharge capacities increased to 277.2 mA.h.g-1 and 308.5 mA.h.g-1, respectively.
