基于支持向量机和磁记忆技术的管道缺陷深度的定量化反演研究

金属管道表面往往存在不同深度的腐蚀缺陷。金属磁记忆检测技术是目前唯一能对铁磁性构件的早期损伤进行诊断的无损检测技术,然而磁记忆原始信号本身并不能直接实现对管道腐蚀缺陷深度特征的定量化识别,进而无法实现对管道腐蚀程度的预警。针对该问题,采用支持向量机方法建立了管道缺陷深度的定量化反演模型,利用该模型对管道上深度为1~15mm的腐蚀缺陷进行了多次反演,反演结果的平均误差为2.398mm,平均均方根误差为3.205mm,结果表明,模型对管道腐蚀缺陷深度的定量化反演是可行的。研究结果可为该领域的研究提供一定的参考,且具有较高的实际应用价值。     

Synthesis and characterization of a titanium phosphate-tellurite glass for Faraday rotators

This work is focused on investigation of thermal, structural, optical, magnetic, and magneto-optical properties of novel titanium phosphate-tellurite glass applied as Faraday rotators. The glass belonging to the system 35Li₂O–10Al₂O₃–5TiO₂–45P₂O₅–5TeO₂ was prepared by a nonconventional wet route of raw materials processing, followed by melting-quenching-annealing steps. Some important physical properties of the investigated glass have been measured and calculated, providing knowledge related to glass compactness, electronic structure, glass forming capability, etc. XRD analysis evidenced an amorphous network structure of the investigated glass. The optical absorption in the Vis domain is mainly due to Ti³⁺ ions and Te₂ clusters formed during the glass melting process. A relatively low optical absorption is noticed over 600 nm that activates a significant Faraday magneto-optical effect. Photoluminescence bands in the blue, red, and infrared domains are observed, caused by Te₂ clusters formed during the glass melting process. The magnetization in dependency on applied magnetic field reveals a complex behavior of the glass, depending on temperature. Thus, it is found a ferromagnetic behavior up to 2000 Oe, a paramagnetic component up to 40 000 Oe, followed by a diamagnetic one over 40 000 Oe. Faraday rotation angle and Verdet constant values in the visible domain are correlated with the reduced TeO₂ content of the glass.     

磁性生物炭非均相类Fenton体系去除水中四环素

采用先浸渍后热解的方法制备了磁性生物炭材料,并使用XRD、XPS、VSM对制备的材料进行了表征。结果表明,制备的磁性生物炭主要的活性物质为γ-Fe2O3。采用磁性生物炭非均相类Fenton体系处理水中四环素(TC),当初始TC质量浓度为200 mg/L,pH=7,H2O2投加量为19.8 mmol/L,磁性生物炭投加量为3 g/L时,处理效果最佳。加入抗坏血酸可以加速铁循环过程,明显改善·OH的生成,进而增强了TC去除率。     

Iron oxide-Palladium core-shell nanospheres for ferromagnetic resonance-based hydrogen gas sensing

Interfaces of ferromagnetic transition metals such as Iron, Cobalt, and Nickel with non-magnetic palladium are of interest due to their unique magnetic and spintronic properties. These interfaces enable ferromagnetic resonance (FMR) based sensing of hydrogen gas. In the present work, we synthesized Fe₃O₄–Pd core-shell nanospheres via a one-pot synthesis method using the thermal decomposition of Fe³⁺ acetylacetonate in the presence of a reducing agent to produce the Fe₃O₄ core, followed by the reduction of a Pd²⁺ precursor to form the pure Pd shell. We found that our in-situ synthesized core-shell nanostructure is magnetically active and shows excellent H₂ gas sensing properties. The effect of reversible hydrogen gas absorption on the magnetism of Fe₃O₄–Pd core-shell nanospheres was investigated. The hydrogen-induced ferromagnetic-resonance (FMR) peak shift amounted to 30% of the peak linewidth for the virgin state of the sample. In addition, in the presence of hydrogen gas, we observed a fully reversible decrease in the FMR peak linewidth by about two times. This was accompanied by a nearly doubling of the FMR peak height. Response and recovery times of about 2 and 50 s, respectively, were extracted from the measurements. All the data was collected using a mix of just 3% hydrogen in a nitrogen carrier gas.     

Estimation of magnetic island width by the fluctuations of electron cyclotron emission radiometer on J-TEXT

The width of a magnetic island is an important parameter for the quantitative analysis of magnetohydrodynamic-related physics. An electron cyclotron emission radiometer(ECE) is a powerful tool that can be used to obtain this width, which can usually be determined from the flat temperature distribution at the O-point phase or the maxima temperature perturbation. An improved method to estimate the width of a magnetic island is proposed in this paper, and it is independent of calibration. With this method and the existing 24-channel ECE system, the width of a rotation magnetic island can be estimated. Additionally, by filtering the fluctuation ECE signal, the evolution of the magnetic island can be obtained. The results of this method are consistent with those of the integrated magnetic probe signals, which represent the relative change of the magnetic island.     

Study of physicochemical properties of flutamide-loaded Ocimum basilicum microspheres with ex vivo mucoadhesion and in vitro drug release

Drug which shows extensive first pass effect is difficult task that, needs to be solved by formulators in the pharmaceutical science. The low oral bioavailability (49%) of flutamide may be due to poor wettability, low aqueous solubility and extensive first pass effect. The aim of present investigation was to prepare flutamide loaded microspheres and incorporate it into suppositories for rectal delivery to avoid first pass effect and enhance residence time. Flutamide loaded mucoadhesive microspheres of Ocimum Basilicum mucilage (OBM) were prepared using spray drying and characterized by percent production yield, encapsulation efficiency, particle size, zeta potential, polydispersity index, DSC, SEM, XRPD, in vitro drug release and stability studies. Moreover, ex vivo mucoadhesion was investigated using falling liquid film technique to determine the adhesion of microspheres to sheep rectal mucosa. The microspheres had nearly spherical shape and size about 2.53?μm. The encapsulation efficiency and mucoadhesion of optimized formulation MBF10 were found to be 69.6?±?2.3% and 89.01?±?2.18%, respectively. Percent CDR of optimized flutamide loaded mucoadhesive microspheres was found to be 88.7?±?1.3 at 7?h. In conclusion, OBM microparticles based suppository could be used to deliver drug through rectal delivery.     

磁性石墨烯/聚氨酯柔性复合材料的制备及自修复效能

为了提高复合材料的导电、导热及自修复性能，在传统共混法的基础上采用化学沉积法将四氧化三铁（Fe₃O₄）修饰到石墨烯上，得到磁性石墨烯，并将其与聚氨酯、碳纳米管共混后经磁场干预控制石墨烯片层的排列得到磁性石墨烯/聚氨酯柔性复合材料。采用SEM、Raman、FTIR对柔性复合材料的微观形貌、分子结构进行表征，并通过激光导热仪、四探针电阻率测定仪和万能试验机分析磁场调控对复合材料电、热、力学以及修复性能的影响。结果表明：磁场下柔性复合材料中的石墨烯片层排列规则，且层次分明，轮廓清晰可见；其热扩散系数相比于未加磁场提高了10 %~12 %，且在高温下具有稳定性，缺陷修复时间减少了50 %；对比出现缺陷前及修复后的复合材料发现，表面电阻率和抗拉强度分别相差0.006Ω·cm和2.4MPa，而无磁场环境下的变化量是其 3～4倍。     

基于摄动法的表贴式永磁电机转子偏心空载气隙磁场计算

采用摄动法解析计算表贴式永磁电机转子偏心空载气隙磁场,以无量纲的偏心扰动量作为摄动变量,可解决表贴式永磁电机内转子结构和外转子结构的转子偏心磁场解析问题。根据气隙区域及永磁体区域的边界条件求解拉普拉斯方程和泊松方程,通过矢量磁位推导出气隙磁通密度的解析表达式,进而应用麦克斯韦应力张量法计算不平衡磁拉力,并将解析法结果与有限元法结果进行比较,发现二者一致性较好,验证了该方法的正确性和有效性。     

Feasible Preparation of a Thin‐Film Composite Nanofiltration (TFC NF) Membrane with Enhanced Skin–Substrate Adhesion and Compaction Resistance: In Situ Construction of Rigid–Flexible Polymer Composited Microspheres (CPs) in the Casting Solution

Novel microspheres (CPs) composited by rigid and flexible polymers are synthesized and embedded in the supporting membranes to enhance both the skin–substrate adhesion and compaction resistance of the thin‐film composite (TFC) nanofiltration membranes. The CPs are in situ formed in the casting solution after the rigid poly(p‐phenylene terephthamide) (PPTA) is produced in the flexible poly(m‐phenylene isophthalamide) (PMIA) solution. Then the PPTA/PMIA in situ blending membranes are prepared by using the NIPs method, and the TFC NF membranes are fabricated via interfacial polymerization on them. The CPs are characterized via polarizing microscopy and TEM. The surface morphology and chemical composition of the blended membranes are characterized by using FESEM, AFM, FTIR, and WCA, respectively. As the results show, the supporting membrane with higher PPTA content exhibits higher permeability, thermal stability, and compaction resistance. Moreover, the adhesion strength between the TFC functional layer and the supporting membrane is improved significantly. It is proposed that this improvement can be attributed to the CPs that are exposed on the top surface of the supporting membrane, which leads to a great enhancement because of the anchoring effect between the functional layer and the CPs.