Probing the magnetization switching with in-plane magnetic anisotropy through field-modified magnetoresistance measurement

Effective probing current-induced magnetization switching is highly required in the study of emerging spin-orbit torque(SOT)effect.However,the measurement of in-plane magnetization switching typically relies on the giant/tunneling magnetoresistance measurement in a spin valve structure calling for complicated fabrication process,or the non-electric approach of Kerr imaging technique.Here,we present a reliable and convenient method to electrically probe the SOT-induced in-plane magnetization switching in a simple Hall bar device through analyzing the MR signal modified by a magnetic field.In this case,the symmetry of MR is broken,resulting in a resistance difference for opposite magnetization orientations.Moreover,the feasibility of our method is widely evidenced in heavy metal/ferromagnet(Pt/Ni_(20)Fe_(80) and W/Co_(20)Fe_(60)B_(20))and the topological insulator/ferromagnet(Bi_(2)Se_(3)/Ni_(20)Fe_(80)).Our work simplifies the characterization process of the in-plane magnetization switching,which can promote the development of SOT-based devices.

Behavior of fractional quantum Hall states in LLL and 1LL with in-plane magnetic field and Landau level mixing:A numerical investigation

By exactly solving the effective two-body interaction for a two-dimensional electron system with layer thickness and an in-plane magnetic field, we recently found that the effective interaction can be described by the generalized pseudopoten- tials （PPs） without the rotational symmetry. With this pseudopotential description, we numerically investigate the behavior of the fractional quantum Hall （FQH） states both in the lowest Landau level （LLL） and first excited Landau level （1LL）. The enhancements of the 7/3 FQH state on the 1LL for a small tilted magnetic field are observed when layer thickness is larger than some critical values, while the gap of the 1/3 state in the LLL monotonically reduced with increasing the in-plane field. From the static structure factor calculation, we find that the systems are strongly anisotropic and finally enter into a stripe phase with a large tilting. With considering the Landau level mixing correction on the two-body interaction, we find the strong LL mixing cancels the enhancements of the FQH states in the 1LL.

Phase diagram and collective modes in Rashba spin–orbit coupled BEC: Effect of in-plane magnetic field

We studied the system of pure Rashba spin–orbit coupled Bose gas with an in-plane magnetic field. Based on the mean field theory, we obtained the zero temperature phase diagram of the system which exhibits three phases, plane wave（PW） phase, striped wave（SW） phase, and zero momentum（ZM） phase. It was shown that with a growing in-plane field,both SW and ZM phases will eventually turn into the PW phase. Furthermore, we adopted the Bogoliubov theory to study the excitation spectrum as well as the sound speed.

Shape Anisotropy and Resonance Mode Guided Reliable Interconnect Design for In-plane Magnetic Logic

Dipole coupled nanomagnets controlled by the static Zeeman field can form various magnetic logic interconnects.However, the corner wire interconnect is often unreliable and error-prone at room temperature. In this study, we address this problem by making it into a reliable type with trapezoid-shaped nanomagnets, the shape anisotropy of which helps to offer the robustness. The building method of the proposed corner wire interconnect is discussed,and both its static and dynamic magnetization properties are investigated. Static micromagnetic simulation demonstrates that it can work correctly and reliably. Dynamic response results are reached by imposing an ac microwave field on the proposed corner wire. It is found that strong ferromagnetic resonance absorption appears at a low frequency. With the help of a very small ac field with the peak resonance frequency, the required static Zeeman field to switch the corner wire is significantly decreased by ~21 m T. This novel interconnect would pave the way for the realization of reliable and low power nanomagnetic logic circuits.

Isolated corticospinal tract in a patient with intracerebral hemorrhage A diffusion tensor tractography and transcranial magnetic stimulation study

Diffusion tensor tractography allows visualization of the corticospinal tract （CST） in three dimensions. Transcranial magnetic stimulation offers a unique advantage in that it can distinguish between the corticospinal tract and the non-CST by analyzing the characteristics of a motor-evoked potential. A 15 year-old female showed right hemiparesis, due to intracerebral hemorrhage in the left corona radiata, and the posterior limb of the internal capsule. Diffusion tensor tractography revealed that the tracts of both hemispheres originated from the precentral gyrus, and descended through the known CST pathway. Specifically, the tract of the affected hemisphere descended through an isolated area in the leukomalactic lesion at the posterior limb level. In addition, the characteristics of the motor-evoked potential obtained from the right hand when stimulating the hot spot of the left motor cortex corresponded to a CST. In conclusion, we report on a patient with intracerebral hemorrhage who showed an isolated CST in a leukomalactic lesion. This result suggests the importance of saving the adjacent area or penumbra around a hematoma after an intracerebral hemorrhage.

Determination of the in-plane anisotropy field in hexagonal systems via rotational magnetization: Theoretical model and Monte Carlo simulations

The magnetic anisotropy field in thin films with in-plane uniaxial anisotropy can be deduced from the VSM magnetization curves measured in magnetic fields of constant magnitudes. This offers a new possibility of applying rotational magnetization curves to determine the firstand second-order anisotropy constant in these films. In this paper we report a theoretical derivation of rotational magnetization curve in hexagonal crystal system with easy-plane anisotropy based on the principle of the minimum total energy. This model is applied to calculate and analyze the rotational magnetization process for magnetic spherical particles with hexagonal easy-plane anisotropy when rotating the external magnetic field in the basal plane. The theoretical calculations are consistent with Monte Carlo simulation results. It is found that to well reproduce experimental curves, the effect of coercive force on the magnetization reversal process should be fully considered when the intensity of the external field is much weaker than that of the anisotropy field. Our research proves that the rotational magnetization curve from VSM measurement provides an effective access to analyze the in-plane anisotropy constant K3 in hexagonal compounds, and the suitable experimental condition to measure K3 is met when the ratio of the magnitude of the external field to that of the anisotropy field is around 0.2.

IMS-PCR快速检测单核细胞增生李斯特氏菌

采用免疫磁分离技术(Immuno-magnetic Separation,IMS)和Polymerase Chain Reaction(PCR)结合的方法来检测单核细胞增生李斯特氏菌(Listeria monocytogenes)。依据单核细胞增生李斯特氏菌的iap基因序列设计特异性引物,作为PCR扩增的靶基因,经PCR反应得到片段长度为230 bp。结果表明,所建立的IMS与PCR结合方法较常规方法简便、快速、灵敏度高,有很好的应用前景。

MICROWAVE PERMEABILITY SPECTRA OF SPUTTERED Fe-Co-B SOFT MAGNETIC THIN FILMS

Permeability characteristics of sputtered soft magnetic Fe40Co40B20 thin films are investigated in the range of O. 5 to 5 GHz by a shortened microstrip transmission line perturbation method. Excellent microwave permeability is achieved at 0.4 Pa argon pressure： fr is 3.32 GHz, the real and imaginary part of permeability at 0.5 GHz are 104 and 61, respectively. In addition, the thickness effect on permeability is also studied. The minimum damping can be achieved at the thinnest film. Different sources contributed to in-plane anisotropy are discussed briefly. The deviation between the peak frequency of the imaginary part and the zero-crossing frequency of the real part of permeability is also presented.

Imatinib mesylate in clinically suspected gastric stromal tumors

Gastrointestinal stromal tumors （GISTs） occur most frequently in the stomach.Diagnosis of gastric GIST is not always clear before surgery.Flexible endoscopy may suggest the nature of the lesion （a bulky tumor with preserved mucosa）; however,biopsy is rarely diagnostic.Therefore,diagnostic medication with safe drugs may provide a feasible way under such conditions after an informed consent is obtained.Based on the excellent efficacy of imatinib mesylate （IM） in the treatment of GIST,we successfully applied it in the diagnostic medication of two patients with clinically suspected gastric stromal tumors.In conclusion,the diagnostic medication with IM can be an alternative option for patients with suspected GIST that can not be confirmed pathologically.

Electronic property and topological phase transition in a graphene/CoBr_(2) heterostructure

Recently,significant experimental advancements in achieving topological phases have been reported in van der Waals(vdW)heterostructures involving graphene.Here,using first-principles calculations,we investigate graphene/CoBr_(2)(Gr/CoBr_(2))heterostructures and find that an enhancement of in-plane magnetic anisotropy(IMA)energy in monolayer CoBr_(2) can be accomplished by reducing the interlayer distance of the vdW heterostructures.In addition,we clarify that the enhancement of IMA energy primarily results from two factors:one is the weakness of the Co-d_(xy) and Co-d_(x^(2)-y^(2)) orbital hybridization and the other is the augmentation of the Co-d_(yz) and Co-d_(z)2 orbital hybridization.Meanwhile,calculation results suggest that the Kosterlitz–Thouless phase transition temperature(TKT)of a 2D XY magnet Gr/CoBr_(2)(23.8 K)is higher than that of a 2D XY monolayer CoBr_(2)(1.35 K).By decreasing the interlayer distances,the proximity effect is more pronounced and band splitting appears.Moreover,by taking into account spin–orbit coupling,a band gap of approximately 14.3 meV and the quantum anomalous Hall effect(QAHE)are attained by decreasing the interlayer distance by 1.0 A.Inspired by the above conclusions,we design a topological field transistor device model.Our results support that the vdW interlayer distance can be used to modulate the IMA energy and QAHE of materials,providing a pathway for the development of new low-power spintronic devices.

磁共振成像动态增强联合弥散加权成像诊断乳腺癌的准确性

目的探讨磁共振成像动态增强联合弥散加权成像(Diffusion-weighted Imaging,DWI)诊断乳腺癌的准确性。方法方便选取2021年1月—2023年4月岳阳市中心医院收治的343例疑似乳腺癌患者为研究对象,所有患者均行磁共振动态增强成像、多b值DWI检查及两者联合检查,金标准为病理诊断。对比动态增强扫描、DWI、联合诊断的检出结果及诊断效能。结果联合诊断的灵敏度、特异度、准确度为89.58%、96.69%、92.71%,高于动态增强扫描(75.00%、85.43%、79.59%)及DWI(76.56%、86.75%、81.05%)单一诊断,差异有统计学意义(χ^(2)=15.611、12.297、27.013,P均<0.05)。结论磁共振成像动态增强联合DWI对乳腺癌的诊断准确度显著高于单一诊断,在乳腺癌早期诊断中效能显著。

电动汽车轮毂永磁无刷直流电机控制系统的速度控制

轮毂电机驱动是电动汽车采取的一种新型驱动方式。针对电动汽车轮毂永磁无刷直流电机的多变量、高度非线性以及强耦合的特点,将电机控制系统的转速控制器设计为模糊神经网络PID调节器,通过鸡群算法和改进BP算法分别对模糊神经网络进行优化和训练,实现模糊神经网络PID调节器的最优参数输出。系统仿真和实验分析验证表明,基于模糊神经网络PID转速调节器的电机控制系统具有很强的转速跟踪、抑制超调、抗干扰、鲁棒性等动态性能。

新型磁集成零电压零电流软开关全桥变流器

提出了一种新型的磁集成零电压零电流软开关移相全桥DC/DC变流器。该磁集成变流器将3个电感和1个变压器集成于同一磁心中,变压器的漏感同时用做储能电感,传统全桥电路中的输出滤波电感也被移去。因此,二次侧整流管可工作于零电流模式,整流管上的电压尖刺也可被输出电压箝位。另外,变压器中的励磁电流作为电流源为一次侧开关管的寄生电容充放电,因此一次侧开关管在全负载范围内均可实现零电压开通。与分立元件方案相比,该磁集成方案具有元件少、体积小、成本低和磁损小的优点。制作了300 W、350~400 V输入、12 V输出的样机,验证了理论分析的正确性。

两种具有氢键网络的Ni(Ⅱ)-咪唑配合物的晶体结构和磁性

合成了两种配合物晶体［Ｎｉ（ｉｍ ）６］（ＮＯ３）（ＯＨ）（Ｈ２Ｏ）４ （Ⅰ） 和［Ｎｉ（ｉｍ ）４（Ｈ２Ｏ）２］［Ｃ６Ｈ４（ＣＯＯ）２］（Ⅱ）（ｉｍ ＝ Ｃ３Ｈ４Ｎ２）． 晶体结构测定表明， 晶体（Ⅰ）属于六方晶系， 空间群Ｐ６３／ｍ ， ａ＝０．８９８ ５（１０） ｎｍ ， ｃ＝ ２．１００ ２（４） ｎｍ ， Ｖ＝ １．４６８ ５（４） ｎｍ ３， Ｚ＝ ２， Ｒ＝ ０．０４３， Ｒｗ ＝ ０．０４５． 晶体（Ⅱ）属单斜晶系， 空间群Ｃ２／ｃ， ａ＝ ２．２２０ ７（４） ｎｍ ， ｂ＝ ０．７６６ ５（２） ｎｍ ， ｃ＝ １．６０４ ３（３） ｎｍ ， β＝１２０．６０（３）°， Ｖ＝ ２．３５０ ３（９） ｎｍ ３， Ｚ＝ ４， Ｒ＝ ０．０５６， Ｒｗ ＝ ０．０７９． 两种配合物在结构上的突出特点是通过氢键形成了三维无限伸展的氢键电荷传递体系， 对分子间电子传递有调节和促进作用，从而对晶体的磁性质产生了一定影响．

ATP生物发光技术在微生物检测中的应用

ATP(三磷酸腺苷)生物发光法作为一种不断完善成熟的微生物快速检测方法,具有简便、快速、高灵敏度等优点。对该方法的历史发展、检测原理、目标物提取方法、应用领域和最新研究成果等做重点介绍,并对ATP生物发光法的应用现状和发展方向进行总结和展望。

利用1H—MRS早期评估乳腺癌新辅助化疗疗效的研究

目的探讨利用氢质子磁共振波谱（1H—MRS）检测肿瘤组织的复合胆碱（tCho）浓度，早期评估乳腺癌新辅助化疗疗效的价值。方法对72例拟行新辅助化疗的乳腺癌患者（肿瘤T分期在T1C以上），在化疗前1周内及化疗第1疗程结束后2周内各进行1次乳腺MRI（包括。H—MRS）及超声检查。所有患者化疗前均经组织学穿刺活检确诊，在新辅助化疗疗程结束后均进行手术治疗。将手术病理切片与化疗前穿刺病理片比较，将患者分为有显著疗效组和无显著疗效组。采用受试者工作特性曲线（ROC）确定以化疗前后tCho浓度变化判断化疗效果的最佳界值，并比较以tCho浓度下降值判断化疗效果与病理学评价结果的一致性。结果72例患者中，有显著疗效64例，无显著疗效8例。有显著疗效组化疗前、后tCho浓度分别为（4．55±2．75）mmol／L和（1．06±1．32）mmol／L，差异有统计学意义（P〈0．01）；而无显著疗效组为（4．61±2．57）mmol／L和（3．72±2．20）mmol／L，差异无统计学意义（P〉0．05）。两组MRI及超声测量病灶大小在化疗前后差异均无统计学意义（均P〉0．05）。ROC曲线分析结果显示，tCho浓度降低1．39mmol／L时，判断效果最好，曲线下面积为0．980，灵敏度为0．969，特异度为0．875。72例患者中，有显著疗效62例，无显著疗效10例，与病理学评价结果有较好的一致性，Kappa=0．746（P〈0．001）。结论在新辅助化疗早期，利用1H—MRS检测化疗前后tCho浓度的变化可以评估化疗的疗效，而MRI及超声检查测量病灶大小的变化不能有效评估化疗的疗效。

输卵管积液的CT、MRI诊断

目的探讨输卵管积液的CT及MRI影像学特点。方法回顾性分析26例(双侧发病14例,共40个病灶)手术病理证实的输卵管积液患者的CT及MRI表现,包括输卵管脓肿17例、输卵管积水15例、输卵管卵巢脓肿8例。结果输卵管积液呈弯曲管状、多房状或串珠状形态,尖端指向子宫角。输卵管积脓MRI呈等或稍长T1、长T2信号、DWI呈高信号,5例显示液-液平面;输卵管积水以水样信号为主,3例T1WI呈等信号、DWI呈高信号。输卵管积脓CT密度较输卵管积水稍高,输卵管积水以水样密度为主。输卵管或输卵管卵巢脓肿管壁较厚、强化较明显、周围改变较显著。结论输卵管积液MRI有一定特征,容易和盆腔其它囊性病变鉴别。

腺性膀胱炎的CT和MR表现与鉴别诊断

目的探讨腺性膀胱炎的CT和MR影像特点及鉴别诊断要点。方法搜集21例经病理证实的腺性膀胱炎的CT和MR资料,全部病例均做平扫及增强检查。结果草坪状增厚型11例,弥漫型5例,结节隆起型3例,混合型2例。结论腺性膀胱炎主要表现为草坪状或弥漫性的膀胱壁增厚,增强后呈轻度强化。重视腺性膀胱炎和其它膀胱肿瘤合并存在的可能,增强扫描对于膀胱内多灶病变的定性有重要的价值。

MRI多种成像技术在小肝癌诊断中的价值

目的探讨MRI多种成像技术在诊断小肝癌中的价值。方法回顾性分析32例经手术或穿刺病理证实的小肝癌患者的影像学资料。所有患者均行多序列MR检查。所用序列包括快速小角度激发梯度回波T1WI、半傅立叶采集快速自旋回波T2WI及脂肪抑制、弥散加权成像、三维增强血管成像或动态增强。观察各序列肝癌结节的MRI表现,同时与肿瘤的病理类型对照,并对两种增强方法进行对比。结果32例有49个肿瘤结节。T1WI肿瘤结节呈均匀低信号30个,不均匀低信号14个,等、高信号5个。T2WI结节呈均匀高信号19个,不均匀高信号15个,等、低信号内含散在高信号5个。DWI所有肿瘤结节呈高信号。两组增强表现为对比剂快进快出强化模式者34个(69.38%),快进慢出者14个(28.57%),慢进慢出者1个(0.20%)。肿瘤的MRI表现与其组织病理改变有关。三维增强血管成像能显示部分肿瘤的供血动脉。动态增强组对比噪声比(CNR)优于CE-MRA(t值为5.10,P<0.05)。结论MR多序列联合应用能正确、客观地反映小肝癌的形态和性质,是诊断小肝癌有价值的方法。

上颈椎肿瘤的诊断与手术治疗

目的：探讨上颈椎肿瘤的诊断和治疗方法。方法：分析上颈椎肿瘤１５ 例临床资料，观察其临床表现、影像学改变及手术疗效。结果：上颈椎肿瘤多见于Ｃ２ 椎体，以转移性肿瘤为主，其次为巨细胞瘤。对１４ 例进行术后６ 个月～５ 年（ 平均２９ 个月） 随访，术后７１ ％ （１０／１４） 获得满意疗效。结论：ＭＲＩ 对上颈椎肿瘤早期诊断具有重要价值。对上颈椎肿瘤如无全身性转移病灶，患者全身情况允许，应尽早行手术治疗。