基于ANSYS的高温超导混合磁轴承悬浮力分析

基于商用电磁场有限元软件ANSYS以及Bean临界态模型,对由圆柱形高温超导块材、永磁体和超导线圈组成的新型高温超导混合磁轴承的电磁场分布及悬浮力进行了仿真分析,研究了超导线圈对高温超导混合磁轴承悬浮力的影响,同时还通过实验测试了悬浮力。结果表明:仿真与实验具有较好的一致性,使用软件仿真方便可行,其结果较为准确可靠,可为高温超导混合磁轴承的设计和优化提供理论依据。     

Temperature Dependent In-Plane Anisotropic Magnetoresistance in HfTe_5 Thin Layers

We report the observation of in-plane anisotropic magnetoresistance and planar Hall effect in non-magnetic HfTe₅ thin layers.The observed anisotropic magnetoresistance as well as its sign is strongly dependent on the critical resistivity anomaly temperature T_p.Below T_p,the anisotropic magnetoresistance is negative with large negative magnetoresistance.When the in-plane magnetic field is perpendicular to the current,the negative longitudinal magnetoresistance reaches its maximum.The negative longitudinal magnetoresistance effect in HfTe₅ thin layers is dramatically different from that induced by the chiral anomaly as observed in Weyl and Dirac semimetals.One potential underlying origin may be attributed to the reduced spin scattering,which arises from the in-plane magnetic field driven coupling between the top and bottom surface states.Our findings provide valuable insights for the anisotropic magnetoresistance effect in topological electronic systems and the device potential of HfTe5 in spintronics and quantum sensing.     

Diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate content in lube base oils in terahertz regime

We investigate the diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate (ZDDP) mixed with lube base oil (LBO) at different concentrations using terahertz time-domain spectroscopy (THzTDS).When the concentration exceeds 6.78%,the characteristic absorption peaks exhibit significantly shift,and the absorption coefficient peak value is nonlinear against concentration.Moreover,the absorption coefficients of mixed samples follow the Beer’s law at a concentration below 6.78%.The quantitative analysis enables a strategy for monitoring the formulation of lubricating oil in real time.     

New monolithic stir-cake-sorptive extraction for the determination of polar phenols by HPLC

A novel porous monolith has been prepared and used as a sorbent in stir-cake-sorptive extraction (SCSE). The monolithic material was prepared by in-situ copolymerization of allyl thiourea (AT) and divinylbenzene (DB) in the presence of dimethylformamide as a porogen solvent. To optimize the polymerization conditions, different monoliths with different ratios of functional monomer to porogenic solvent were prepared, and their extraction efficiency was investigated in detail. The monolith was characterized by elemental analysis, scanning electron microscopy, mercury intrusion porosimetry, and infrared spectroscopy. Analysis of polar phenols in environmental water samples by a combination of ATDB-SCSE and HPLC with diode-array detection was selected as a model for the practical application of the new sorbent. Several extraction conditions, including extraction and desorption time, pH, and ionic strength of the sample matrix were optimized. The results showed that the new monolith had high affinity for polar phenols and could be used to extract them effectively. Under the optimum conditions, low detection (S/N?=?3) and quantification (S/N?=?10) limits were achieved for the phenols, within the ranges 0.18–0.90 and 0.59–2.97 μg L^?1, respectively. The linearity of the method was good, and the method enabled simple, practical, and low-cost extraction of these analytes. The distribution coefficients between ATDB and water (K _ATDB/W) were calculated for the phenolic compounds and compared with K _O/W. Finally, the proposed method was successfully applied to the determination of the compounds in three environmental water samples, with acceptable recovery and satisfactory repeatability.

Preparation of stir cake sorptive extraction based on polymeric ionic liquid for the enrichment of benzimidazole anthelmintics in water,honey and milk samples

In this work, a new stir cake sorptive extraction (SCSE) using polymeric ionic liquid monolith as sorbent was prepared. The sorbent was obtained by in situ copolymerization of an ionic liquid, 1-allyl-3-methylimidazolium bis[(trifluoro methyl)sulfonyl]imide (AMII) and divinylbenzene (DB) in the presence of N,N-dimethylformamide. The influence of the content of ionic liquid and the porogen in the polymerization mixture on extraction performance was studied thoroughly. The physicochemical properties of the polymeric ionic liquid were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The usefulness of SCSE–AMIIDB was demonstrated by the enrichment of trace benzimidazole anthelmintics. Several parameters affecting the extraction efficiency were investigated, and under the optimized conditions, a simple and effective method for the determination of trace benzimidazoles residues in water, milk and honey samples was established by coupling SCSE–AMIIDB with high performance liquid chromatography/diode array detection (SCSE–AMIIDB–HPLC/DAD). Results indicated that the limits of detection (S/N = 3) for target compounds were 0.020–0.072 μg L⁻¹, 0.035–0.10 μg L⁻¹ and 0.026–0.076 μg L⁻¹ in water, milk and honey samples, respectively. In addition, an acceptable reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations (RSD) of less than 9% and 11%, respectively. Finally, the established AMII–SCSE–HPLC/DAD method was successfully applied for the determination of benzimidazoles residues in milk, honey and environmental water samples. Recoveries obtained for the determination of benzimidazole anthelmintics in spiking samples ranged from 70.2% to 117.6%, with RSD below 12% in all cases.     

A new circulating two-cell structure for stimulated Brillouin scattering phase conjugation mirrors with 1-J load and 10-Hz repetition rate

A new approach to realize high-energy and high-power stimulated Brillouin scattering phase conjugation mirrors （SBS-PCMs） is described.The reflectivity of SBS-PCM is investigated under a 10-Hz repetition rate and a high energy load.The relationship between reflectivity and input energy is examined experimentally with different PCM structures,focus lengths,and medium cell structures.A medium cell with a circulating structure is designed,and its advantage is demonstrated through an experimental comparison with traditional PCM structures.The 30-cm focus lens and 150-cm collimation lens are optimized when the input energy reaches 1010 mJ at 10-Hz repetition rate.Therefore,a reflectivity of 84.7% and a higher energy load using the circulating two-cell structure are achieved.     

膨胀机力学模拟试验装置

为了适应当前发展的需要,本试验装置可以研究G-M制冷机中的膨胀机在动态环境下能否可靠工作,为其提供了强有力的试验平台。本装置可以单独实现水平面的旋转或垂直面的翻转,还可以同时实现水平面的旋转和垂直面的翻转。对G-M制冷机扩大应用领域是不可或缺的试验装置。     

大型回热换热器的降温实验

大型低温配件的降温试验复杂和多变,文中针对大型回热换热器的降温进行了研究。将回热换热器置于特制的冷箱内,利用液氮作为冷源,氦气做为载冷剂为换热器提供降温条件;隔膜压缩机为循环氦气提供循环压力。试验前将换热器上面布置9支传感器,传感器所采集的数据自动记录并保存在上位机内,同时绘制降温曲线,为大型回热换热器的降温研究提供了数据。     

Carbon dots-enhanced luminol chemiluminescence and its application to 2-methoxyestradiol determination

In this study, the fluorescent carbon dots (CDs) of good biocompatibility and low toxicity was prepared by a carbonation route, and a strong enhancement effect of CDs on the luminol-K₃Fe(CN)₆ chemiluminescence (CL) system was observed. 5?±?1?nm CDs were used as catalysts to enhance the reaction sensitivity. In the presence of 2-methoxyestradiol (2-ME), the CL intensity of CDs-luminol-K₃Fe(CN)₆ was significantly inhibited. The relative CL intensity was linearly related to the 2-ME concentration in the range of 1.0?×?10^?9 –1.0?×?10^?7?g?mL^-1 with a lower detection limit of 4.1?×?10^?10?g?mL^?1. As a preliminary application, the highly sensitive method was successfully applied to the determination of 2-ME in both pharmaceutical preparation and serum samples with satisfactory results. The possible mechanism of CL reaction catalyzed by CDs was investigated and the CDs played a role of catalyst in the reaction which could promote the generation of oxygen radicals.

It could be concluded that the enhancement effect on CL by CDs was attributed to the formation of oxygen radicals. The oxidation reaction of luminol was accelerated by oxygen radicals, which led to the enhanced CL emission.     

工艺参数对TSMTG法制备单畴YBCO样品的影响

用顶部籽晶熔融织构法(TSMTG)制备了30min直径的YBCO超导块，研究了不同的工艺条件对样品宏观形貌、织构取向和磁浮力的影响，比较了3种样品在零场冷条件下的排斥力和场冷条件下的吸引力。结果发现：由籽晶控制取向生长的单畴YBCO样品宏观形貌是以顶部籽晶为中心的4个结晶扇区，有单一的c轴取向，零场冷条件下的排斥力和场冷条件下的吸引力最大；籽晶成核但没有控制取向生长的YB-CO样品宏观形貌是以顶部籽晶为中心的多个(大于4个)扇区，相邻扇区间夹角不等，c轴取向不一致，磁浮力性能居中；非籽晶成核生长的多畴YBCO样品，上表面是以籽晶为中心的一个边长约1cm的四方结晶区，其余部分是自发成核的多晶，样品c轴取向杂乱，磁浮力很低。