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Revised global vertically integrated remanent magnetization model of the oceanic lithosphere with comparison to LCS-1 model and MSS-1 magnetic measurements 被引量:2
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作者 ShiDa Sun Hui Li +3 位作者 JinSong Du Pan Zhang Chao Chen PengFei Liu 《Earth and Planetary Physics》 2025年第3期653-666,共14页
The lithospheric magnetic field is an important component of the geomagnetic field,and the oceanic lithosphere exhibits distinct characteristics.Because of its formation mechanisms,evolutionary history,and geomagnetic... The lithospheric magnetic field is an important component of the geomagnetic field,and the oceanic lithosphere exhibits distinct characteristics.Because of its formation mechanisms,evolutionary history,and geomagnetic field polarity reversals,the oceanic lithosphere has significant remanent magnetization,which causes magnetic anomaly stripes parallel to the mid-ocean ridges.However,it is difficult to construct a high-resolution lithospheric magnetic field model in oceanic regions with relatively sparse data or no data.Using forward calculated lithospheric magnetic field data based on an oceanic remanent magnetization(ORM) model with physical and geological foundations as a supplement is a feasible approach.We first collect the latest available oceanic crust age grid,plate motion model,geomagnetic polarity timescale,and oceanic lithosphere thermal structure.Combining the assumptions that the paleo geomagnetic field is a geocentric axial dipole field and that the normal oceanic crust moves only in the horizontal direction,we construct a vertically integrated ORM model of the normal oceanic crust with a known age,including the intensity,inclination,and declination.Both the ORM model and the global induced magnetization(GIM) model are then scaled from two aspects between their forward calculated results and the lithospheric magnetic field model LCS-1.One aspect is the difference in their spherical harmonic power spectra,and the other is the misfit between the grid data over the oceans.We last compare the forward calculated lithospheric magnetic anomaly from the scaled ORM and GIM models with the Macao Science Satellite-1(MSS-1) observed data.The comparison results show that the magnetic anomalies over the normal oceanic crust regions at satellite altitude are mainly contributed by the high-intensity remanent magnetization corresponding to the Cretaceous magnetic quiet period.In these regions,the predicted and observed anomalies show good consistency in spatial distribution,whereas their amplitude differences vary across regions.This result suggests that regional ORM construction should be attempted in future work to address these amplitude discrepancies. 展开更多
关键词 oceanic remanent magnetization lithospheric magnetic field LCS-1 Macao Science Satellite-1
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Elevated temperature magnetic microstructures and demagnetization mechanism for grain boundary diffused dual-main-phase(Nd,Ce)-Fe-B magnets 被引量:2
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作者 Yifei Xiao Lele Zhang +7 位作者 Wei Yang Tao Liu Qisong Sun Xiaolong Song Yikun Fang Anhua Li Minggang Zhu Wei Li 《Journal of Materials Science & Technology》 2025年第4期10-23,共14页
The combination of dual-main-phase(DMP)(Nd,Ce)-Fe-B magnets and grain boundary diffusion process(GBDP)is currently a research topic for obtaining high-cost performance materials in rare earth permanent magnet fields.T... The combination of dual-main-phase(DMP)(Nd,Ce)-Fe-B magnets and grain boundary diffusion process(GBDP)is currently a research topic for obtaining high-cost performance materials in rare earth permanent magnet fields.The novel structural features of GBDP(Nd,Ce)-Fe-B magnets give a version of different domain reversal processes from those of non-diffused magnets.In this work,the in-situ magnetic domain evolution of the DMP magnets was observed at elevated temperatures,and the temperature demagnetization and coercivity mechanism of the GBDP dual-main-phase(Nd,Ce)-Fe-B magnets are discussed.The results show that the shell composition of different types of grains in DMP magnets is similar,while the magnetic microstructure results indicate the Ce-rich grains tend to demagnetize first.Dy-rich shell with a high anisotropic field caused by GBDP leads to an increase in the nucleation field,which enhances the coercivity.It is found that much more grains exhibit single domain characteristics in the remanent state for GBDP dual-main-phase(Nd,Ce)-Fe-B magnets.In addition,the grains that undergo demagnetization first are Ce-rich or Nd-rich grains,which is different from that of non-diffused magnets.These results were not found in previous studies but can be intuitively characterized from the perspective of magnetic domains in this work,providing a new perspective and understanding of the performance improvement of magnetic materials. 展开更多
关键词 Magnetic microstructures Dual-main-phase (Nd Ce)-Fe-B Diffused Dy Rare earth permanent magnet materials Grain boundary diffusion process(GBDP)
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In-situ reduction mechanism of hematite by bastnaesite during suspension magnetization roasting 被引量:1
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作者 Wen-bo LI Shao-kai CHENG +1 位作者 Rui QU Ji-jia CHEN 《Transactions of Nonferrous Metals Society of China》 2025年第3期965-974,共10页
To explore the spontaneous magnetization of iron-bearing rare earth ores during suspension roasting,binary minerals containing hematite and bastnaesite were used to investigate the effects of the roasting temperature,... To explore the spontaneous magnetization of iron-bearing rare earth ores during suspension roasting,binary minerals containing hematite and bastnaesite were used to investigate the effects of the roasting temperature,roasting time,and bastnaesite-to-hematite mass ratio on in-situ reduction of hematite in a N_(2)atmosphere.Relevant analytical tests were used to explore the mineral phase evolution during roasting,the magnetism and microstructure of the roasted products,the phase composition,and the surface element valence of concentrate.It was found that magnetic separation of the iron concentrate afforded an iron grade of 68.87%and a recovery of 93.18%under the optimum roasting conditions.During roasting,bastnaesite decomposed to generate CO_(2)and CO,and the compact structure of hematite was gradually destroyed,resulting in microcracks.Subsequently,the CO entered the surface of the hematite through the microcracks and reacted to form a magnetite shell,and the magnetite-encapsulated hematite particles were recovered via low-intensity magnetic separation. 展开更多
关键词 BASTNAESITE HEMATITE magnetization roasting in-situ reduction
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Effects of Magnetization of Background Ions on Wave Spectra of 2D Complex Plasma
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作者 Zhang Hui Zhang Lanxin +2 位作者 Sun Shulin Yang Fang Kong Wei 《南开大学学报(自然科学版)》 北大核心 2025年第1期22-33,共12页
The longitudinal and transverse waves of 2D magnetized complex plasma based on the drivendissipative Langevin dynamics simulation are investigated.The modified Yukawa potential with including the magnetization of back... The longitudinal and transverse waves of 2D magnetized complex plasma based on the drivendissipative Langevin dynamics simulation are investigated.The modified Yukawa potential with including the magnetization of background ions is used to account for the interaction of the charged dust particles.The simulation results are compared with the existing theories including quasilocalized charge approximation and randomphase approximation.In the weak magnetization regime,the wave spectra obtained from Yukawa simulation and modified Yukawa simulation basically are the same.In the strong magnetization regime,the magnetization of background ions and temperature ratio of background electrons to background ions play effects on the wave spectra of the system,particularly for the strongly coupled state.The dust acoustic waves in the weakly coupled state basically are not influenced by the magnetization of background ions. 展开更多
关键词 wave spectrum dusty plasma magnetic field
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Modification of slow relaxation of magnetization behavior via substituent change on two neutral mononuclear dysprosium(Ⅲ) single-molecule magnets
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作者 Leilei Li Libo Zhang +4 位作者 Anzhi Huang Shuang Liu Wenzhen Wang Hongjiang Yu Yiquan Zhang 《Journal of Rare Earths》 2025年第9期1901-1908,共8页
Structural fine-tuning is of significant importance to enhance the magnetic anisotropy and elucidate the magneto-structural relationship for single molecule magnets(SMMs).For this purpose,two mononuclear Dy^(3+) SMMs:... Structural fine-tuning is of significant importance to enhance the magnetic anisotropy and elucidate the magneto-structural relationship for single molecule magnets(SMMs).For this purpose,two mononuclear Dy^(3+) SMMs:[Dy{HB(pz)3}2(Sal)](1) and [Dy{HB(pz)_(3)}_(2)(MeO-Sal)](2),where HB(pz)_(3)^(-)represents hydro tris(pyrazolyl)borate,Sal denotes salicyiaidehyde and MeO-Sal stands for 5-methoxysalicylaldehyde,were designed and synthesized.Single crystal X-ray diffraction tests show that the two SMMs have very similar eight-coordinated molecule structures,although the introducing of-MeO substituent on salicyiaidehyde ligand induces the changes on the molecule packing mode and the space group.Both the two SMMs have a Dy-O_(aryloxidebond) that is significantly shorter than other Dy-O/N bonds,which defines the orientation of main anisotropy axis of the ground Kramers doublets and engenders the slow relaxation of the magnetization behavior,as evidenced by the magnetic susceptibility and the ab initio calculation.Though with an electron-donating substituent on the axial Sal ligand in 2,the collective magnetic anisotropy is not enhanced and the corresponding magneto-structural relationship is discussed based on the experimental and theoretical calculation results.In addition,as neutral molecules,1 and 2 are soluble in several common organic solvents,like CH_(2)Cl_(2),CHCl_(3),THF and so on. 展开更多
关键词 DYSPROSIUM Rare earths Single molecule magnet Magnetic property Magnetic anisotropy Slow magnetic relaxation
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Ultralow-Vertical-Current Magnetization Switching Effect in an All Van Der Waals 2D Heterostructure
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作者 Hao Wu Li Yang +6 位作者 Gaojie Zhang Wen Jin Jie Yu Bichen Xiao Ahmed Annas Wenfeng Zhang Haixin Chang 《Chinese Physics Letters》 2025年第2期239-248,共10页
The manipulation of magnetization and spin polarization using electrical currents represents a fundamental breakthrough in spintronics.It has formed the foundation for data storage and next-generation computing system... The manipulation of magnetization and spin polarization using electrical currents represents a fundamental breakthrough in spintronics.It has formed the foundation for data storage and next-generation computing systems.Spin-transfer torque(STT)and spin-orbit torque(SOT)have emerged as prominent mechanisms in current-driven magnetization switching.However,these approaches typically require critical current densities in the range of 10^(6) to 10^(9) A·cm^(-2),resulting in significant heat generation during data writing processes.Herein,we report the discovery of an ultralow-vertical-current magnetization switching effect in a van der Waals ferromagnetic/ferroelectric heterostructure based on the modulation of the critical magnetic field(H_(C))using small vertical currents,with a critical current density as low as 1.81A·cm^(-2) and an average effective field(H_(eff)/J_(C))as high as 150.3mT·A^(-1)·cm^(2).This unique magnetization switching effect with ultralow-critical-vertical-current densities typically six to nine orders of magnitude lower than those of the STT and SOT provides a new transformative and viable pathway for developing next-generation spintronic and quantum technologies. 展开更多
关键词 magnetization critical typically
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Influence of cooling atmosphere on the structure,magnetization,and dielectric properties of CaBaCo_(4)O_(7)
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作者 Gaoshang Gong Minghao Wang +4 位作者 Ruoshui Liu Yang Wu Lichen Wang Yongqiang Wang Baogen Shen 《Chinese Physics B》 2025年第4期585-589,共5页
CaBaCo_(4)O_(7)has been widely studied because of its distinctive structure and magnetic properties.This study examined the influence of different cooling atmospheres on the structure,magnetic properties,and dielectri... CaBaCo_(4)O_(7)has been widely studied because of its distinctive structure and magnetic properties.This study examined the influence of different cooling atmospheres on the structure,magnetic properties,and dielectric behavior of CaBaCo_(4)O_(7).Samples were cooled under different atmospheric conditions to assess these influences.Our findings indicate that reduced oxygen content leads to increased lattice distortion.Since oxygen atoms play a crucial role in mediating magnetic exchange,oxygen deficiency disrupts long-range magnetic order and promotes short-range antiferromagnetic interactions.Additionally,the cooling atmosphere significantly impacts grain size,thereby affecting the dielectric constant and dielectric loss.In the argon-cooled CaBaCo_(4)O_(7)(Ar)sample,oxygen deficiency reduced dielectric permittivity and increased dielectric loss. 展开更多
关键词 CaBaCo_(4)O_(7) cooling atmosphere magnetization DIELECTRIC
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Nature of the 1/3 Magnetization Plateau in Spin-1/2 Kagome Antiferromagnets
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作者 Li-Wei He Xinzhe Wang +1 位作者 Shun-Li Yu Jian-Xin Li 《Chinese Physics Letters》 2025年第9期163-168,共6页
We investigate the origin of the 1/3 magnetization plateau in the S=1/2 kagome antiferromagnetic Heisenberg model using the variational Monte Carlo and exact diagonalization methods,to account for the recent experimen... We investigate the origin of the 1/3 magnetization plateau in the S=1/2 kagome antiferromagnetic Heisenberg model using the variational Monte Carlo and exact diagonalization methods,to account for the recent experimental observations in YCu_(3)(OH)_(6+x)Br_(3-x)and YCu_(3)(OD)_(6+x)Br_(3-x).We identify three degenerate valencebond-solid(VBS)states forming a√3×√3 unit cell.These states exhibit David-star patterns in the spin moment distribution with only two fractional values-1/3 and 2/3,and are related through translational transformations.While the spin correlations in these VBS states are found to be short-range,resembling a quantum spin liquid,we show that they have a vanishing topological entanglement entropy and thus are topologically trivial many-body states.Our theoretical results provide strong evidence that the 1/3 magnetization plateau observed in recent experiments arises from these√3×√3 VBS states with fractional spin moments. 展开更多
关键词 kagome antiferromagnetic heisenberg model variational monte carlo spin moment distribution valencebond solid states exact diagonalization magnetization plateau spin kagome antiferromagnets exact diagonalization methodsto
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High-frequency complex permeability calculation for metallic soft magnetic particles with easy magnetization plane in non-magnetic medium
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作者 Liangrui Tan Donglin He +5 位作者 Zhibiao Xu Guowu Wang Shengyu Yang Shaoyong Leng Ruilong Li Tao Wang 《Chinese Physics B》 2025年第11期254-261,共8页
Soft magnetic composites made from metallic magnetic particles with an easy magnetization plane(referred to as easy-plane metallic soft magnetic composites(SMC))are considered ideal materials for the next generation o... Soft magnetic composites made from metallic magnetic particles with an easy magnetization plane(referred to as easy-plane metallic soft magnetic composites(SMC))are considered ideal materials for the next generation of power electronic devices.This advantage is attributed to their ability to maintain high permeability at elevated frequencies.Despite these advantages,a definitive mathematical model that connects the high-frequency magnetic properties(e.g.,effective permeability)of easy-plane metallic SMCs to the intrinsic properties of the particles is still lacking.In this work,a theoretical calculation model for the effective permeability of easy-plane metallic SMCs was formulated.This model was derived from a skin effect-corrected Landau-Lifshitz-Gilbert(LLG)equation and integrated with effective medium theory incorporating inter-particle interaction.To validate the model,we prepared samples of easy-plane Y_(2)Co_(17)particle/PU SMCs with varying particle sizes and volume fractions.The experimental results showed a strong agreement with the calculated values.This research offers critical theoretical backing for the design and optimization of soft magnetic materials intended for high-frequency applications. 展开更多
关键词 easy-plane material HIGH-FREQUENCY soft magnetic composites complex permeability Landau-Lifshitz-Gilbert(LLG)equation
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国产磁锚定设备在减Trocar腹腔镜胆囊切除术中的应用分析
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作者 马佳 张苗苗 +3 位作者 吕毅 刘学民 严小鹏 汤博 《中华肝胆外科杂志》 北大核心 2026年第1期20-23,共4页
目的分析国产磁锚定设备用于减Trocar腹腔镜胆囊切除术的效果。方法回顾分析2025年3月至7月在西安交通大学第一附属医院行磁锚定减Trocar腹腔镜胆囊切除术的患者资料。最终入组33例患者,其中男性13例,女性20例,年龄(50.7±11.8)岁... 目的分析国产磁锚定设备用于减Trocar腹腔镜胆囊切除术的效果。方法回顾分析2025年3月至7月在西安交通大学第一附属医院行磁锚定减Trocar腹腔镜胆囊切除术的患者资料。最终入组33例患者,其中男性13例,女性20例,年龄(50.7±11.8)岁。分析患者手术时间、术中出血量、术中设备不良事件(磁性组织夹滑脱、磁性组织夹与磁性抓钳离合故障)发生情况、术野暴露情况,术后第1天与第2天手术切口Wong-Baker面部表情疼痛量表评分、术后并发症(包括切口感染、切口出血、胆漏等)等。结果33例患者中胆囊结石伴慢性胆囊炎27例(81.8%)、胆囊息肉4例(12.1%)、胆囊结石合并胆囊息肉1例(3.0%)、胆囊腺肌症1例(3.0%)。所有患者均顺利实施了磁锚定减Trocar腹腔镜胆囊切除术,手术时间为(58.7±20.1)min,术中出血量为(8.0±3.5)ml。术中磁锚定设备未出现不良事件,磁性组织夹与磁性抓钳离合过程顺利,无滑脱、离合故障等,锚定磁体与磁性组织夹能够提供足够的牵拉力,术野显露满足术中操作所需。33例患者术后第1天、第2天手术切口疼痛评分分别为2(1,4)分、1(0,2)分。术后1个月复查所有患者均无并发症发生。结论国产磁锚定设备用于减Trocar腹腔镜胆囊切除术能够有效减少腹壁Trocar数量,且安全、有效。 展开更多
关键词 胆囊疾病 磁外科 磁锚定设备 腹腔镜胆囊切除术
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空气流态化磁网筛分磁选机的磁系及磁场特征
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作者 侯新凯 王颖 +2 位作者 张君豪 孙可为 黄树森 《中南大学学报(自然科学版)》 北大核心 2026年第1期25-34,共10页
针对钢渣中RO相(FeO-MgO-MnO-CaO连续固溶体)细粒弱磁性矿物在干法分选中效率低的问题,研发了一种空气流态化磁网筛分高梯度磁选机。首先,该设备将粉体稀相流态化技术与微米级丝网磁介质相结合,构建出强磁网过滤器,形成高梯度磁场,实现... 针对钢渣中RO相(FeO-MgO-MnO-CaO连续固溶体)细粒弱磁性矿物在干法分选中效率低的问题,研发了一种空气流态化磁网筛分高梯度磁选机。首先,该设备将粉体稀相流态化技术与微米级丝网磁介质相结合,构建出强磁网过滤器,形成高梯度磁场,实现物料的单颗粒精准分选;其次,为优化磁系结构,基于网格化磁场实测与磁能计算法,重点对比了圆形(传统)与方形(新型)磁系的性能;最后,揭示了磁系配置与磁场特征之间的关联性。研究结果表明:方形磁系采用竖直对置双励磁线圈结构,铁芯居中并通过导磁材料连接,形成“上下贯通、左右对称”的双闭合磁路,使磁阻降低至圆形磁系的40%;方形磁系竖直面磁场呈反置马鞍形分布,水平面磁场呈方形盆状分布,磁能转化率达59.6%,是圆形磁系的1.83倍,能量利用率显著提高。方形磁系有效抑制漏磁,提升磁场强度与稳定性,更适合高梯度磁选分选要求。 展开更多
关键词 流态化磁选机 RO相分选 磁系 磁场 钢渣
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致密砂岩气层核磁共振响应特征分析及孔隙度校正
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作者 李静 高遥 +4 位作者 刘翔 贾春明 高子扬 黄锐捷 肖亮 《核电子学与探测技术》 北大核心 2026年第2期277-285,共9页
选取准噶尔盆地南缘二叠系清水河组致密砂岩地层10块代表性岩心,分别开展完全饱含水及5种甲烷(CH_(4))驱水状态下的核磁共振实验,研究了CH_(4)驱水对核磁共振T2谱,含气饱和度对核磁孔隙度及核磁共振T_(2)几何均值(T_(2lm))的影响规律。... 选取准噶尔盆地南缘二叠系清水河组致密砂岩地层10块代表性岩心,分别开展完全饱含水及5种甲烷(CH_(4))驱水状态下的核磁共振实验,研究了CH_(4)驱水对核磁共振T2谱,含气饱和度对核磁孔隙度及核磁共振T_(2)几何均值(T_(2lm))的影响规律。结果表明,完全饱含水状态下,核磁共振T_(2)谱呈现分布较宽的双峰,T_(2)谱收敛点大于1000 ms。随着CH_(4)驱替时间延长(含气饱和度增加),核磁共振T_(2)谱可动峰主峰位置逐渐向左移动,且幅度降低,核磁孔隙度、T_(2lm)与完全饱含水状态下的差异也逐渐增大。相同含气饱和度下,孔隙结构越好,核磁孔隙度降低越明显。利用岩心实验结果,建立了基于储层分类的致密砂岩气层核磁孔隙度校正模型。利用其能够有效地校正岩石孔隙空间饱含天然气对核磁孔隙度的影响,得到地层的真实孔隙度。计算的孔隙度与岩心分析孔隙度之间的平均相对误差为7.42%。 展开更多
关键词 核磁共振 CH_(4)驱水 含气饱和度 核磁孔隙度
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磁外科助力肝胆外科微创技术再优化
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作者 刘学民 刘行 《中华肝胆外科杂志》 北大核心 2026年第1期1-4,共4页
磁外科技术主要包括磁力吻合、磁力再通、磁场调控、磁场锚定和磁体示踪五大类, 在肝胆外科微创领域应用效果显著, 前景广阔。具体而言, 磁力吻合技术大幅缩短了腹部大血管的吻合时间及肝移植的无肝期。磁场锚定技术推动了腹腔镜减Troca... 磁外科技术主要包括磁力吻合、磁力再通、磁场调控、磁场锚定和磁体示踪五大类, 在肝胆外科微创领域应用效果显著, 前景广阔。具体而言, 磁力吻合技术大幅缩短了腹部大血管的吻合时间及肝移植的无肝期。磁场锚定技术推动了腹腔镜减Trocar和单孔腹腔镜手术的进步。磁力再通技术则以微创方式治疗复杂胆道狭窄, 避免了二次手术。未来, 磁外科的发展需要强化磁性材料研究、深入探索磁场生物学效应, 并加速产业发展。通过持续加强基础研究和产业转化, 为更多患者带来获益。 展开更多
关键词 磁力学 肝胆外科 磁力吻合 磁场锚定 磁力再通
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船舶磁场动态检测中磁场反演校正方法
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作者 周国华 夏帅 +2 位作者 吴轲娜 奉之翔 凌志 《兵工学报》 北大核心 2026年第1期407-415,共9页
船舶磁场动态检测具有测量设备简单、隐蔽性好、建造成本低等优势,已成为世界各国海军争相发展的一种船舶磁场检测方式,但磁场动态检测过程中姿态等航行动态因素变化会导致较大的磁场测量误差。基于船舶磁场动态检测的基本原理,建立船... 船舶磁场动态检测具有测量设备简单、隐蔽性好、建造成本低等优势,已成为世界各国海军争相发展的一种船舶磁场检测方式,但磁场动态检测过程中姿态等航行动态因素变化会导致较大的磁场测量误差。基于船舶磁场动态检测的基本原理,建立船舶磁场动态检测数学模型,据此详细模拟分析各动态因素对测量磁场的影响程度,并提出计及各动态因素影响的测量磁场反演校正方法,即通过动态测量多源数据构建船舶等效磁性反演校正模型,用Lasso回归求解,继而通过反演等效磁性参数实现动态测量过程的磁场数据校正。物理缩比模型实验结果表明,船舶在4个不同航行方向上的磁场动态测量中,当航向动态变化幅值为4°时,校正前的最大绝对误差为374 nT、相对误差不小于3.44%,校正后磁场的最大绝对误差为146 nT、相对误差不超过2.35%。新方法对提高船舶磁场动态检测准确度及推广应用具有很好的工程指导意义。 展开更多
关键词 磁场动态检测 等效磁性模型 磁偶极子 磁场校正
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双并列转子永磁同步电机设计与分析
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作者 陈阳 陶大军 +1 位作者 戈宝军 刘鑫洋 《电工技术学报》 北大核心 2026年第2期442-456,共15页
针对并行对驱类机械设备的驱动需求,该文提出一种双并列转子永磁同步电机(DRPMSM)。采用该电机驱动具有系统效率高、体积小、旋转同步性严格、无齿轮传动等优势,该文对其设计方法和电磁特性进行研究。首先,阐述DR-PMSM的拓扑结构,定义... 针对并行对驱类机械设备的驱动需求,该文提出一种双并列转子永磁同步电机(DRPMSM)。采用该电机驱动具有系统效率高、体积小、旋转同步性严格、无齿轮传动等优势,该文对其设计方法和电磁特性进行研究。首先,阐述DR-PMSM的拓扑结构,定义新增设计参数,分析其运行原理,研究各部分磁路对电机的作用效果;其次,探究此类电机的一般性通用设计流程,给出各个关键环节的设计方法和确定原则;再次,在此基础上,对一台DR-PMSM进行设计,构建有限元模型,分析电机的电磁特性,验证电机的运行原理和设计方法的正确性,并揭示各种电磁特性不对称或不平衡的原因;然后,探讨关键参数改变对关键性能的影响规律,给出关键参数选取和优化调整的思路;最后,研制一台DR-PMSM,搭建试验平台并进行测试,验证所提设计方法的可靠性。 展开更多
关键词 双并列转子 永磁同步电机 电磁设计 电磁特性
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强剩磁条件的非凸优化反演方法研究
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作者 朱丹 曹丹平 《中国石油大学学报(自然科学版)》 北大核心 2026年第1期23-34,共12页
磁异常模量稀疏反演是获取高分辨率剩磁模型的有效方法,其本质是磁性模型的L_(0)范数极小。但L_(0)范数计算求解困难,传统方法通过凸近似函数逼近L_(0)范数,虽能实现目标函数梯度的稳定计算,却难以控制反演模型体积。构建包含数据拟合... 磁异常模量稀疏反演是获取高分辨率剩磁模型的有效方法,其本质是磁性模型的L_(0)范数极小。但L_(0)范数计算求解困难,传统方法通过凸近似函数逼近L_(0)范数,虽能实现目标函数梯度的稳定计算,却难以控制反演模型体积。构建包含数据拟合项、模型约束项和L_(0)范数约束项的磁异常模量反演优化模型,采用迭代硬阈值方法实现L_(0)范数的稳定迭代计算,从而实现强剩磁条件反演模型边界的清晰刻画及尺度可控。通过理论模型实验验证方法有效性与稳定性,并应用于江苏冶山地区,构建成矿岩体的磁性模型,为深部找矿提供科学依据。结果表明,该方法可在保证数据拟合精度的前提下,实现模型尺度渐近线性收敛,从而获得目标体积的强剩磁反演模型。 展开更多
关键词 磁法勘探 剩余磁化强度 稀疏反演 L_(0)范数 江苏冶山
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基于巯基化磁性介孔硅胶的固相萃取-原子荧光光谱法测定食品中痕量汞
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作者 张惠贤 操凤 +5 位作者 石思怡 王爱华 徐芬 崔文文 姚晶晶 王明锐 《中国无机分析化学》 北大核心 2026年第1期14-23,共10页
本研究旨在建立一种高效、快速、选择性测定食品中痕量汞的方法。通过溶剂热法及后续的巯基化修饰,成功制备了一种新型巯基功能化磁性介孔二氧化硅(Thiol-functionalized Magnetic Mesoporous Silica,记为mSS@Fe_(3)O_(4))吸附剂。将该... 本研究旨在建立一种高效、快速、选择性测定食品中痕量汞的方法。通过溶剂热法及后续的巯基化修饰,成功制备了一种新型巯基功能化磁性介孔二氧化硅(Thiol-functionalized Magnetic Mesoporous Silica,记为mSS@Fe_(3)O_(4))吸附剂。将该吸附剂用于磁性固相萃取(MSPE),结合原子荧光光谱法(AFS),构建了一种分析食品中痕量汞的新方法。通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)等手段对材料进行了表征,证实了巯基已成功接枝到磁性介孔二氧化硅表面。系统优化了萃取过程中的关键参数,包括样品pH值、吸附时间、吸附剂用量、洗脱液组成和上样体积。结果表明,归因于材料的介孔结构和高比表面积,吸附平衡在1 min内即可达到,实现了对Hg^(2+)的快速富集。在最优条件下,该吸附剂对Hg^(2+)的理论最大吸附容量(qm)为67.89 mg/g;在回收率保持>90%时,最大上样体积为200 mL,预浓缩因子可达200。该方法具有较宽的pH值(1~13)适用范围和优异的抗基质干扰能力。方法线性范围为0.10~4.0μg/L(相关系数r=0.9996),方法检出限(MDL)为0.012μg/kg,对空白样品进行7次平行测定的相对标准偏差(RSD)为2.4%(n=7)。通过对国家标准物质和多种实际样品(草鱼、大米等)的加标回收实验,验证了方法的准确性和可靠性,回收率在94.0%~106%。该方法集快速、高效、高选择性与高灵敏度于一体,为食品中痕量汞的常规监测提供了有力的技术支持。 展开更多
关键词 磁性固相萃取 原子荧光光谱法 巯基化磁性介孔硅胶 食品分析
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心脏MR参数预测老年扩张型心肌病患者主要不良心血管事件
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作者 尹成俊 田荣华 +2 位作者 邹语嫣 章宏 杨明 《中国介入影像与治疗学》 北大核心 2026年第1期44-49,共6页
目的观察心脏MR(CMR)参数预测老年扩张型心肌病(DCM)患者主要不良心血管事件(MACE)的价值。方法回顾性选取201例接受CMR检查的老年DCM患者,根据随访期间是否发生MACE将其分为MACE组(n=52)与无MACE组(n=149);比较组间临床及CMR资料,以Co... 目的观察心脏MR(CMR)参数预测老年扩张型心肌病(DCM)患者主要不良心血管事件(MACE)的价值。方法回顾性选取201例接受CMR检查的老年DCM患者,根据随访期间是否发生MACE将其分为MACE组(n=52)与无MACE组(n=149);比较组间临床及CMR资料,以Cox回归分析筛选MACE的独立影响因素,采用受试者工作特征(ROC)曲线及Kaplan-Meier生存分析评估各参数单一及联合预测MACE的效能。结果组间纽约心脏病学会(NYHA)心功能分级Ⅲ~Ⅳ占比、左心室射血分数(LVEF)、钆对比剂延迟强化(LGE)占比、左心室整体纵向应变(LVGLS)、细胞外体积分数(ECV)及初始T1值Z评分差异均有统计学意义(P均<0.05)。单因素及多因素Cox回归分析显示,LVEF、ECV及初始T1值Z评分均为MACE的独立影响因素(P均<0.05),其曲线下面积分别为0.778、0.703及0.703;ROC曲线及Kaplan-Meier生存分析结果显示,三者联合的整体预测效能最佳。结论LVEF、ECV及初始T1值Z评分均有助于预测老年DCM患者MACE风险;三者联合可进一步提高预测效能。 展开更多
关键词 心肌病 扩张型 磁共振成像 预后
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基于交轴磁场调节的漏磁通可控永磁同步电动机最小弱磁电流控制
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作者 全力 金志伟 +2 位作者 徐磊 朱孝勇 范文杰 《江苏大学学报(自然科学版)》 北大核心 2026年第1期55-63,共9页
为满足电动汽车应用领域对驱动电动机大转矩、宽调速范围、高效率等的需求,结合漏磁可控型永磁(flux leakage controllable permanent magnet,FLCPM)电动机高速低磁通、重载高磁通的特性,提出一种基于交轴磁场调节的弱磁电流最小调速控... 为满足电动汽车应用领域对驱动电动机大转矩、宽调速范围、高效率等的需求,结合漏磁可控型永磁(flux leakage controllable permanent magnet,FLCPM)电动机高速低磁通、重载高磁通的特性,提出一种基于交轴磁场调节的弱磁电流最小调速控制策略.利用交轴磁场重构弱磁控制时i_(d)、i_(q)电流分配,有限调节永磁体漏磁磁通,间接实现气隙磁通控制.在此基础上,为减小漏磁通变化对电流分配计算及去磁电流计算的影响,引入最小i_(s)电流弱磁约束条件与在线调节判断,优选i_(d)、i_(q)分配量,提高弱磁运行效率.进行FLCPM电动机的i_(q)电流弱磁控制和最小弱磁电流控制试验,并分析了其电流大小、调速特性和弱磁效率特点.结果表明:在FLCPM电动机上的传统i_(d)电流弱磁存在过度弱磁,且最小弱磁电流控制拥有更小的is电流、更宽的调速范围和更高的弱磁效率,i_(s)电流最高减少了2.83%、弱磁效率最高可达91.0%. 展开更多
关键词 永磁电动机 漏磁可控 i_(q)电流弱磁 最小弱磁调速 最小i_(s)电流弱磁 高弱磁效率
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磁锚定技术在减Trocar腹腔镜胆囊切除术中的应用分析
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作者 张莉 张苗苗 +4 位作者 白纪刚 沙焕臣 李赟 吕毅 严小鹏 《中华肝胆外科杂志》 北大核心 2026年第1期15-19,共5页
目的分析磁锚定技术在减Trocar腹腔镜胆囊切除术中应用的安全性与疗效。方法回顾性分析2019年4月至2023年12月在西安交通大学第一附属医院肝胆外科行磁锚定减Trocar腹腔镜胆囊切除术的162例患者临床资料,其中男性43例,女性119例,年龄(44... 目的分析磁锚定技术在减Trocar腹腔镜胆囊切除术中应用的安全性与疗效。方法回顾性分析2019年4月至2023年12月在西安交通大学第一附属医院肝胆外科行磁锚定减Trocar腹腔镜胆囊切除术的162例患者临床资料,其中男性43例,女性119例,年龄(44.6±13.0)岁。162例患者中胆囊结石合并慢性胆囊炎116例(71.6%),胆囊息肉22例(13.6%),急性结石性胆囊炎16例(9.9%),胆囊结石伴慢性胆囊炎合并胆囊息肉7例(4.3%),胆囊腺肌症1例(0.6%)。分析患者手术时间、术中出血量、中转开腹或中转为三孔情况,打电话随访术后并发症(发热、胆漏、切口出血、切口感染、切口血肿、胆管狭窄等)。术后第1天采用Wong-Baker面部表情疼痛量表对患者疼痛进行评分。结果162例患者均成功实施了磁锚定减Trocar腹腔镜胆囊切除术(两孔法),无中转开腹及中转三孔手术情况。162例患者手术时间为(43.6±15.4)min,术中出血量为(8.1±6.3)ml,术后第1天疼痛评分为(1.8±0.5)分。所有患者术后无发热、胆漏、切口出血、切口感染、切口血肿、胆管狭窄等发生。结论磁锚定减Trocar腹腔镜胆囊切除是一种安全、有效的微创手术方式。 展开更多
关键词 胆囊疾病 磁锚定技术 腹腔镜胆囊切除术
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