M-lump and interactive solutions to a (3 $${+}$$ + 1)-dimensional nonlinear system

Nonlinear Dynamics - This paper aims at computing M-lump solutions for the $$(3+1)$$ -dimensional nonlinear evolution equation. These solutions in all directions decline to an identical state...     

压荷载下类岩石材料中的锯齿形裂纹分析

针对类岩石材料的复杂性和非均质性，特别是材料中一些强度相对较弱的晶界的存在等，对形状较为复杂的两种锯齿形裂纹：内张型滑动裂纹和单翼滑动裂纹的应力强度因子进行了分析．结合经典的滑动裂纹模型，讨论了裂纹起裂角、侧压以及翼裂长度等对应力强度因子的影响．分析的结果为进一步研究类岩石材料的断裂损伤机理提供了理论基础．     

Compressed matrix thin film (CMTF)-assisted laser desorption ionization mass spectrometric analysis

The inhomogeneous re-crystallization process of matrix materials is the major concerns associated with matrix assisted laser desorption/ionization (MALDI) analysis. We describe here the approach termed compressed matrix thin film (CMTF) in order to make a uniform matrix deposition. In this approach, solid matrix particles are compressed under 10 MPa of pressure by a compressor that is regularly used in infrared spectroscopic analysis. Then aqueous samples can be deposited on the surface of the matrix film. Major advantages of the CMTF approach are summarized as follows. (1) Reproducible sample preparation procedure. Size and thickness of matrix thin films can be controlled by using a fixed mold.force and known amount of matrix materials. (2) Significantly decreased shot-to-shot variations and enhanced reproducibility. (3) Tolerance for in situ salt washing. Because matrix materials are hydrophobic, salts can be washed away while proteins or peptides are retained on the surface of matrix thin films through hydrophobic interactions. (4) Improved sensitivity. The hydrophobic coating of MALDI sample plate by matrix thin films prevents the spreading of samples across the plate and confines analytes to a small area, leading to increased local concentration. (5) A new means for tissue analysis. Tissue sections can be directly transferred to the uniform surface of matrix materials for reproducible and quantitative comparison of different molecules in different localization. The proposed CMTF should be an enabling technique for mass spectrometric analysis with improved correlations between signal intensities and sample quantities.     

Microstructure,Tribological Behavior,and Corrosion-Resistant Performance of Bonded MoS2 Solid Lubricating Film Filled with Nano-LaF3

The anti-friction and wear-resistant performances of bonded MoS₂ solid lubricating films filled with nano-LaF₃ filler were investigated under in drying wear conditions, the corrosion-resistant performances of bonded lubricating films was evaluated according to ASTM-B117, and the characteristics of the bonded lubricating films were examined by TEM and elemental x-ray map. The wear-resistant performance of the bonded lubricating films filled with nano-LaF₃ filler increases with increasing content of nano-LaF₃ filler within a content range between 0 and 5 wt%, whereas the bonded lubricating films filled with 0.5–1 wt% micro-LaF₃ filler exhibit the better wear-resistant performances. The incorporation of both nano-LaF₃ and micro-LaF₃ filler leads the increase of the coefficient of friction of the bonded lubricating films. The LaF₃ filler can improve the corrosion-resistant performance of the bonded MoS₂ solid lubricating films, whereas the incorporation of nano-LaF₃ filler is more effective to improve the corrosion-resistant performance of the bonded lubricating films than micro-LaF₃ filler. The improvement in the wear-resistant and corrosion-resistant performances of the bonded lubricating films by the incorporation of the nano-LaF₃ filler is attributed to the strengthened interfacial bonding among the nano-LaF₃ and the MoS₂ lubricant and the polymeric matrix. However, a too high mass fraction of the nano-LaF₃ filler in the bonded lubricating films will increase surface and interface defects, and lead the worsening of corrosion-resistant performance of the bonded lubricating films.     

近置多裂纹相互作用的渐近分析方法

考虑到近置裂纹的强相互作用，提出了一种多裂纹相互作用的渐近分析方法. 经典Kachanov 方法将裂纹表面伪面力分解为两部分：均匀分布部分和非均匀部分，并假设裂纹的相互作用 仅由均匀部分引起，而忽略非均匀部分的影响. 该假设大大简化了分析过程，而且当裂纹间 距不是很小时，有很好的精度. 但当裂纹非常靠近或者沿主荷载方向重叠时，由于裂纹尖端 进入了其它裂纹的应力强化区或者应力屏蔽区，强相互作用使得该假设不再合理，从而带来 较大的误差. 为了提高分析近置多裂纹问题的精度，将裂纹表面伪面力分解为抛物线型分布 部分及高阶部分，考虑抛物线型分布张力对其他裂纹的影响，同样忽略高阶部分的影响. 通 过对三共线裂纹及两平行偏置裂纹两个实例的分析，验证了对于近置裂纹，新渐近方法具有 良好的精度.     

A simple solution-immersion process for the fabrication of superhydrophobic cupric stearate surface with easy repairable property

The present work reports a simple and time-saving method to fabricate cupric stearate film on zinc substrate by a solution-immersion process. Superhydrophobic surfaces are conventionally prepared employing two steps: roughening a surface and lowering its surface energy. The fabrication of superhydrophobic cupric stearate surface is reported using a one-step process by immersing a zinc plate coated with copper into the stearic acid solution, simplifying the complexity of two different steps involved in the conventional methods. The surface of the zinc plate coated with copper is found to be covered with low surface energy cupric stearate film providing the water contact angle of 160 ± 1° with the rolling off properties. In addition, the damaged superhydrophobic surface can restore superhydrophobicity property by immersing the surface into the stearic acid solution again.     

A NECESSARY AND SUFFICIENT CONDITION FOR THEOSCILLATION OF SOLUTIONS OF LIENARD TYPE SYSTEM WITH MULTIPLE SINGULAR POINTS

I.IntroductionJ.R.Graer']andG.VillariI2]gavenecessar\JandsufficientconditionsfortheoscillationofsolutionofLienardsystemf~])~F(x),y~~glXJ(l.l)HanMaoanI3]gaveoscillatirytheoremsforLienardt}'pesystemt'.ithasingularpointi~h(.t/)~F(x),#~~g(x)(1.2)Whereas,aloto…     

各向异性表面光学的格林函数公式及其应用

本文通过对麦克思韦方程组的变换和反演得到各向异性介质的表面光学格林函数.用它计算辐射场可以直接得到s和p偏振波的表示式,因而在计算界面效应时可以自然地引入菲涅耳系数.作为应用,本文计算了当存在界面和薄膜时极化所产生的辐射场.     

Impulsive robust fault-tolerant feedback control for chaotic Lur’e systems

This paper considers the problem of impulsive robust fault-tolerant feedback control for chaotic Lur’e systems. The sufficient condition of the uncertain Lur’e systems possessing integrity against actuator failures is given by using linear matrix inequalities (LMIs), and at the same time, the closed-loop system with impulsive effects is globally asymptotically stable, and it has robustness of parameter uncertainties. An example is given to illustrate obtained result.