Magnetoelastic bending and stability of soft ferromagnetic rectangular plates

I.IntroductionSofar,twokindsofphenomenaofmagnetoelasticinteractiontoferromagneticplatesinappliedmagneticfieldshavebeenfound.Oneisthemagnetoelasticbuchlingorillstabllitytoacantileveredbeam-plateinatransversemagneticfieldt'],thatisthephen1Onlenollot'negiltivemagneticstiffness,whiletheotheristheincreaseofnaturalfrequencyoftheplatewhichisfreelyviratinginanin-planemagneticfieldl=],thatisthephenomenonofpositivemagneticstiffness.Inordertosimulatethesetwokindsofexperimentalphenomena,sometheoreticalmo…     

镍基甲烷化催化剂中的助剂作用 Ⅱ重稀土氧化物添加剂的结构效应和电子效应

应用ＢＥＴ、气相色谱、红外光谱、竞争加氢反应和ＸＰＳ等方法,在以前工作的基础上继续考察了Ｙ２Ｏ３、Ｓｍ２Ｏ３、Ｅｕ２Ｏ３、Ｇｄ２Ｏ３、Ｔｂ４Ｏ７、Ｄｙ２Ｏ３、Ｅｒ２Ｏ３、Ｔｍ２Ｏ３、Ｙｂ２Ｏ３作为添加剂,对镍在γ－Ａｌ２Ｏ３表面的分散度、甲烷化活性、ＣＯ在镍上的吸附态及表面镍原子的电子状态的影响．结果表明,稀土氧化物添加剂不仅明显地提高了金属镍的分散度和甲烷化活性,还直接地影响表面镍原子的电子状态．对不同稀土氧化物,这些效应各异．作者认为,利用稀土氧化物添加剂调节表面镍原子的电子状态,可能成为改进甲烷化催化剂活性的一个有效途径．     

A generalized variational principle and theoretical model for magnetoelastic interaction of ferromagnetic bodies

The quantitative analysis shows that no theoretical model for 3-d magnetoelastic bodies, in literatures to date, can commonly simulate two kinds of distinct experimental phenomena on magnetoelastic interaction of ferromagnetic structures. This makes it difficult to effectively discribe the magnetoelastic mechanical behavior of structures with complex geometry, such as shells. Therefore, it is a key step for simulating magnetoelastic mechanical characteristics of structures with complex geometry to establish a 3-d model which also can commonly characterize the two distinct experimental phenomena. A theoretical model for three dimension magnetizable elastic bodies, which is commonly suitable for the two kinds of experimental phenomena on magnetoelastic interaction of ferromagnetic plates, is presented by the variational principle for the total energy functional of the coupling system of the 3-d ferromagnetic bodies. It is found that for the case of linear isotropic magnetic materials, the magnetic forces obtained by this model include not only the body magnetic force which is the same as that got from the magnetic dipole model, but also a distribution of the magnetic traction on the surface of the magnetizable body. And the value of the traction is equal to the jumping one of the Faraday electromagnetic stress on the two sides of the surface, which does not appear in any model, such as magnetic dipole model and axiomatic model.     

Development of an Optical Fiber Lactate Sensor

Lactate analysis is important in clinical diagnostics and the food industry. An ultrasensitive optical fiber lactate sensor with rapid response time and 50?μm size has been developed. Lactate dehydrogenase (LDH) has been directly immobilized onto an optical fiber probe surface through covalent binding mechanisms. The optical fiber surface is initially activated by silanization, which adds amine groups (–NH₂) to the surface. Aldehyde functional groups (–CHO) are then affixed to the optical fiber surface by employing a bifunctional cross-linking agent, glutaraldehyde. The amino acids of LDH enzyme molecules readily attach to these free -CHO groups on the fiber surface. Optimal immobilization of LDH occurs between 19 and 23 hours of exposure in the enzyme solution. The immobilized LDH enzyme molecules on the fiber surface show high enzymatic activity. The lactate sensor is able to detect lactate with a concentration detection limit of 0.5?μM and the absolute mass detection limit is 8.75 attomoles. Moreover, the sensor rapidly responds to lactate changes and exhibits good reproducibility. The lactate sensor is extremely selective. This immobilized enzyme sensor has been applied to accurately determine the lactate content in food samples.     

载有微量贵金属的n-TiO2电极的光电化学研究

利用在富氧和乏氧溶液中光照下与不光照下测得的极化曲线,研究了载有铂和银的TiO₂电极的光电化学行为及反应机理.在富氧溶液中,光照载有贵金属的TiO₂电极时,贵金属上发生氧的还原反应,其速度与光照与否无关;而在未被贵金属覆盖的电极表面上进行水或其它组份的光氧化;二者组成一对共轭反应,相当于短路的光电化学电池.共轭反应速度一般由氧的还原反应速度控制.增加贵金属的载量能使共轭反应速度增大,外电路中通过的电流等于这一对反应所引起的电流的代数和.根据对极化曲线的分析和界面阻抗的测量结果,可以确定载在TiO₂表面上的铂、银与基底之间的接触基本上是欧姆型的.光照下贵金属中的电子具有与半导体整体相同的费米能级.在含载有贵金属的TiO₂粉末的悬浮液中实现了CN^-和二乙胺的光氧化,其速度随贵金属载量变化的规律可用上述反应机理加以解释.     

Resonant solutions and breathers to the BKP equation

In this paper, we derive resonant and breather solutions from multi-soliton solutions of the B-type Kadomtsev–Petviashvili (BKP) equation of fourth order via the Hirota bilinear method. We first discuss N-soliton solutions of the BKP equation and use the linear superposition principle to generate N-resonant solutions. Subsequently, we construct complexiton and breather solutions and finally, study the dynamics of some selected solutions with the aid of 3D plots, contour plots and density plots.

     

电感耦合等离子体质谱(ICP-MS)法测定地质样品中的金

建立了王水溶解-聚氨酯泡沫塑料吸附-电感耦合等离子体质谱(ICP-MS)法测定地质样品中的金。探讨了振荡时间对回收率的影响,最终确定振荡时间为1h。在优化条件下,方法的相对标准偏差(RSD,n=12)在4.2%~9.0%,加标回收率在92.00%~114.6%,方法检出限为0.11ng/g。方法操作简单,测定精密度高,检出限低,满足大批量地质样品的分析需要。     

Structural Stability,Tunable Electronic,and Optical Properties of XSi2N4/Cs2SnI6 (X = Cr,Mo, W) Heterostructures: First-Principles Studies

Novel optoelectronic and photovoltaic devices are promising, exploiting MoSi₂N₄-based van der Waals (vdW) heterostructures. Herein, six vertical XSi₂N₄/Cs₂SnI₆ (X = Cr, Mo, W) heterostructures are constructed and the atomic structure, stability, and optoelectronic properties via first-principles calculations are investigated. The results of binding energies indicate that XSi₂N₄/SnI₄ is energetically favorable to be established compared to the XSi₂N₄/CsI. Computed charge density differences show that at the XSi₂N₄/SnI₄ interface, there is no significant charge migration or rearrangement, making it unsuitable for use in charge transport devices. It is worth noticing that the built-in electric field induced by electron transfer from CsI to the XSi₂N₄ layer prevents light-induced electron and hole recombination, thereby improving carrier lifetime. Furthermore, the CrSi₂N₄/CsI heterostructure exhibits a wider range of visible light absorption, demonstrating its potential for applications in photoelectronic devices. The electronic and optical properties of XSi₂N₄/Cs₂SnI₆ can be tuned through element substitution. The findings could provide useful guidance for designing XSi₂N₄/Cs₂SnI₆ photoelectronic and photovoltaic devices.     

Entanglement-Assisted Quantum Negacyclic BCH Codes

International Journal of Theoretical Physics - The entanglement-assisted quantum error correcting codes (EAQECCs) are a simple and important class of quantum codes. The entanglement-assisted...     

(3,3)-Connected Three-dimentional Supramolecular Metal Organic Polyhedral Based on Nanometresized Ligand with Magnetism Properties

A three-dimentinal metal organic framework[Co₂(L)Cl(DMF)₂(H₂O)](DMF)₃(H₂O)₃ based on the nanometresized ligand 4,4',4"-[1,3,5-benzenetriyltris(carbonylimino)]trisbenzoic acid was synthesized, and characterized by means of single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetry analysis and magnetism. This obtained structure can be considered to be constructed from 2D layer, which displays the topology of hbc based on Co₂(COO)₃ secondary building unit, and further to be linked into a 3D supramolecular architecture by N-H…O hydrogen bonds. The magnetism of the complex was carried out, which shows ferromagnetic exchange interactions.