magnetic

摘要： We present a Stark–Zeeman spectral line-shape model and the associated numerical code,PPPB,designed to provide fast and accurate line shapes for arbitrary atomic systems for a large range of plasma conditions.PPPB is based on the coupling of the PPP code-a Stark-broadened spectral line-shape code developed for multi-electron ion spectroscopy in hot dense plasmas-and the MASCB code developed recently to generate B-field-dependent atomic physics.The latter provides energy levels,statistical weights,and reduced matrix elements of multi-electron radiators by diagonalizing the atomic Hamiltonian that includes the well know B-dependent term.These are then used as inputs to PPP working in the standard line-broadening approach,i.e.,using the quasi-static ion and impact electron approximations.The effects of ion dynamics are introduced by means of the frequency fluctuation model,and the physical model of electron broadening is based on the semi-classical impact approximation including the effects of a strong collision term,interference,and cyclotron motion.Finally,to account for polarization effects,the output profiles are calculated for a given angle of observation with respect to the direction of the magnetic field.The potential of this model is presented through Stark–Zeeman spectral line-shape calculations performed for various experimental conditions.

摘要： Magnetized laser-produced plasmas are central to many studies in laboratory astrophysics,in inertial confinement fusion,and in industrial applications.Here,we present the results of large-scale three-dimensional magnetohydrodynamic simulations of the dynamics of a laser-produced plasma expanding into a transverse magnetic field with a strength of tens of teslas.The simulations show the plasma being confined by the strong magnetic field into a slender slab structured by the magnetized Rayleigh–Taylor instability that develops at the plasma–vacuum interface.We find that when the initial velocity of the plume is perturbed,the slab can develop kink-like motions that disrupt its propagation.

摘要： This study employs multi-magnetic parametric methods as proxies to measure particulate matter (PM) concentration and spread in Kuwait. It examines the reliability of biomonitoring receptors in the assessment of atmospheric air quality through the utilization of passive biomonitoring methodology using cleaned and non-cleaned Phoenix dactylifera leaves and active biomonitoring through the application of dust samplers in the study area. Four radial sampling areas are located at 2, 6, 10, 14 km from Kuwait’s city center with 10 sampling degree points selected from each radial area, and the closest palm tree in the vicinity to the preselected sampling point with a height of 4 m were sampled. Using a compass, the 4 azithumal points were pin pointed on the selected tree and a 2 × 2 cm dust sampler was attached to each direction at a height of 2 m. The dust sampler was made of clear plastic paper attached with double sided tape. Magnetic susceptibility and Saturation Isothermic Remanent Magnetization (SIRM), Natural Remanent Magnetization (NRM), Hard Isothermal Remanent Magnetization (HIRM), Soft Isothermal Remanent Magnetization (SOFT), HIRM%, soft IRM% and s-ratio were determined for P. dactylifera and dust samplers. Magnetic parameters were mapped to assess the spatial variation of air quality in Kuwait and the values between dust samplers and P. dactylifera. Results indicate that the highest magnetic concentration values for NRM and SIRM for P. dactylifera occurred near Kuwait bay and that the majority of the samples contain ferromagnetic minerals with magnetite most likely from anthropogenic sources. The results of the interpolation models for P. dactylifera and dust samplers as well as the overall mean for dust samplers distinguished short-term PM deposition and concentration and how it is impacted by wind direction in comparison to P. dactylifera which identifies long-term pollution impacts pin pointing PM sources and hotspots.

摘要： The fabrication of directionally driven oil-water separation materials has great significance for the removal of oil spills and organic pollutants.In this study,an oil-water separation aerogel capable of directionally adsorbing oil was designed using an anisotropic wood aerogel with a layered structure and a top-down fabrication strategy.Specifically,a magnetic wood-based superhydrophobic aerogel(methyltrimethoxysilane(MTMS)/Fe_(3)O_(4) wood aerogel)was developed through the in situ coprecipitation of Fe_(3)O_(4) nanoparticles and chemical vapor deposition.Owing to its highly porous structure,lipophilicity,hydrophobicity(water contact angle of 160°),and high compressibility,the MTMS/Fe_(3)O_(4) wood aerogel exhibits excellent oil-water separation performance and compression cycle stability.Additionally,the Fe_(3)O_(4) endows the material with excellent magnetic and photothermal conversion capabilities.These excellent properties make MTMS/Fe_(3)O_(4) wood aerogel a promising recyclable and sustainable oil-water separation material.

摘要： Experiments have identified the Rayleigh–Taylor(RT)instability as one of the greatest obstacles to achieving inertial confinement fusion.Consequently,mitigation strategies to reduce RT growth and fuel–ablator mixing in the hotspot during the deceleration phase of the implosion are of great interest.In this work,the effect of seed magnetic fields on deceleration-phase RT growth are studied in planar and cylindrical geometries under conditions relevant to the National Ignition Facility(NIF)and Omega experiments.The magnetohydrodynamic(MHD)and resistive-MHD capabilities of the FLASH code are used to model imploding cylinders and planar blast-wave-driven targets.Realistic target and laser parameters are presented that suggest the occurrence of morphological differences in late-time RT evolution in the cylindrical NIF case and a measurable difference in spike height of single-mode growth in the planar NIF case.The results of this study indicate the need for target designs to utilize an RT-unstable foam–foam interface in order to achieve sufficient magnetic field amplification to alter RT evolution.Benchmarked FLASH simulations are used to study these magnetic field effects in both resistive and ideal MHD.

摘要： Bi_(0.5)(Na_(0.68)K_(0.22)Li_(0.10))_(0.5)Ti_(1-x)Co_(x)O_(3) lead-free perovskite ceramics(BNKLT-xCo,x=0,0.005,0.010,0.015 and 0.020)were fabricated via the solid-state combustion technique.A small-amount of Co^(2+)ion substitution into Ti-sites led to modification of the phase formation,microstructure,electrical and magnetic properties of BNKLT ceramics.Coexisting rhombohedral and tetragonal phases were observed in all samples using the X-ray diffraction(XRD)technique.The Rietveld refinement revealed that the rhombohedral phase increased from 39%to 88%when x increased from 0 to 0.020.The average grain size increased when x increased.With increasing x,more oxygen vacancies were generated,leading to asymmetry in the bipolar strain(S-E)hysteresis loops.For the composition of x=0.010,a high dielectric constant(ε_(m))of 5384 and a large strain(S_(max))of 0.23%with the normalized strain (d*_(33))of 460 pm·V^(-1) were achieved.The BNKLT-0Co ceramic showed diamagnetic behavior but all of the BNKLT-xCo ceramics exhibited paramagnetic behavior,measured at 50 K.

摘要： Three-dimensional(3D)-printed magnetic soft architectures have attracted extensive attention and research from the engineering and material fields.The force-driven shape deformation of such architectures causes a change in the magnetic field distribution,indicating the capability to convert mechanical energy to electricity.Herein,we fabricate a flexible superhydrophobic and magnetic device by integrating two kinds of 3D printing approaches.The 3D-printed magnetic device(3DMD)exhibits a long-term stable mechanoelectrical conversion capacity under consecutive water droplet dripping.The output current of the 3DMD is higher than that of records in the existing literature.Combined with Maxwell numerical simulation,the mechanoelectrical conversion mechanism of the 3DMD is investigated,further guiding regulation of the diverse parameters.Moreover,three 3DMDs are integrated to light up a commercial light-emitting diode(LED)by a stream of collected rainwater.Such a combined design incorporating energy conversion is believed to promisingly motive advances in the 3D printing field.

摘要： BACKGROUND Magnetic compression anastomosis(MCA)is a novel suture-free reconstruction of the digestive tract.It has been used in gastrointestinal anastomosis,jejunal anastomosis,cholangioenteric anastomosis and so on.The traditional operative outcomes of congenital esophageal atresia and benign esophageal stricture are poor,and there are too many complications postoperatively.AIM To test MCA technology to reconstruct the esophagus in dogs,prior to studying the feasibility and safety of MCA in humans.METHODS Thirty-six dogs were randomized into either the study or control group(n=18 per group).The dogs in the study group were subjected to end-to-end esophageal anastomosis with the magnetic compression device,while those in the control group underwent hand-sewn anastomosis with 4-0 absorbable multifilament Vicryl.We used interrupted single-layer inverting sutures.The anastomosis time,gross appearance,weight and pathology of the anastomosis were evaluated at one month,three months and six months postoperatively.RESULTS The anastomosis time of the MCA group was shorter than that of the hand-sewn group(7.5±1.0 min vs 12.5±1.8 min,P<0.01).In the MCA group,X-ray examination was performed every day to locate the magnetic device in the esophagus before the magnetic device fell off from the esophagus.In the hand-sewn group,dogs did not undergo X-ray examination.One month after the surgeries,the mean weight of the dogs in the hand-sewn group had decreased more than that of the dogs in the MCA group(11.63±0.71 kg vs 12.73±0.80 kg,P<0.05).At 3 mo and 6 mo after the operation,the dogs’weights were similar between the two groups(13.75±0.84 kg vs 14.03±0.82 kg,14.93±0.80 kg vs 15.44±0.47 kg).The number of inflammatory cells in MCA group was lower than that in hand-sewn group on 1 mo after operation.CONCLUSION MCA is an effective and safe method for esophageal reconstruction.The anastomosis time of the MCA group was less than that of the hand-sewn group.This study shows that MCA technology may be applied to human esophageal reconstruction,provided these favorable results are confirmed by more publications.

摘要： High-speed motor has the characteristics of high frequency, high temperature, and more stress, resulting in the field distribution inside the motor being complicated. To better study the electromagnetic characteristics of silicon steel sheet for high-speed motor. In this article, a study on the calculation model of silicon sheet electromagnetic characteristics considers the effects of electromagnetic, stress, and temperature factors. The study is divided into two parts, one is to propose the calculation model of silicon steel sheet’s permeability;the other is to improve the calculation model of silicon steel sheet’s loss. Then, the magnetic field, stress field, and temperature field of a surface mount high speed permanent magnet motor(SMHSPMSM) are analyzed by finite element method(FEM), and the results under the consideration of magnetic, stress, and temperature factors are brought into the calculation model for calculation. Finally, the accuracy of the calculation model for electromagnetic characteristics of silicon steel sheet is verified by comparing the calculated results with the finite element results.

摘要： Intrinsic magnetic topological materials,namely the stoichiometric magnetic compounds possessing both inherent magnetic order and topological electronic states,have attracted tremendous interest in the research of condensed matter physics and materials science[1].Such materials not only bring new opportunities to realize many exotic topological phenomena under time-reversal symmetry breaking,but also show great potential in applications of quantum technology[2].

摘要： 为了提高在测量较高频率时的磁共振设备的灵敏度，射频发射一测量线圈（１０．３０）分成可以激励和可以输出的两个对称的绕组（３２，３４）。绕组中心接头的相互连接，可以利用平衡不平衡转换器（５４）。但其他对称的耦合器件，例如，高频变压器（７０），或合适的同轴电缆（６０，６２）也可以使用。