Impact Damage Identification for Composite Material Based on Transmissibility Function and OS-ELM Algorithm

A method is proposed based on the transmissibility function and the OnlineSequence Extreme Learning Machine (OS-ELM) algorithm, which is applied to theimpact damage of composite materials. First of all, the transmissibility functions of theundamaged signals and the damage signals at different points are calculated. Secondly,the difference between them is taken as the damage index. Finally, principal componentanalysis (PCA) is used to reduce the noise feature. And then, input to the online sequencelimit learning neural network classification to identify damage and confirm the damagelocation. Taking the amplitude of the transmissibility function instead of the accelerationresponse as the signal analysis for structural damage identification cannot be influencedby the excitation amplitude. The OS-ELM algorithm is based on the ELM (ExtremeLearning Machine) algorithm, in-creased training speed also increases the recognitionaccuracy. Experiment in the epoxy board shows that the method can effectively identifythe structural damage accurately.

S-type Er-Yb Co-doped Phosphate Glass Waveguide Amplifier Integrated with Cascaded Multilayer Medium Thin Film Filter

A new S-type of erbium-ytterbium co-doped phosphate glass waveguide amplifier integrated with cascaded multilayer medium thin film filter is proposed,this S-type geometry waveguide structure is used to achieve a long path in a compact chip,and obtained higher gain with lower Er-doped concentration. The cascaded multilayer medium thin film filter is utilized to achieve a broader flattening gain bandwidth.The intrinsical gain spectrum is obtained by solving rate and power propagation equations,the effect of transmittance spectrum of thin film filter on flattening gain is discussed.

Novel Design Solutions for Fishing Reel Mechanisms

Currently, there are various reels on the market regarding the type of mechanism, which achieves the winding and unwinding of the line. The designers have the purpose of obtaining a linear transmission function, by means of a simple and small-sized mechanism. However, the present solutions are not satisfactory because of large deviations from linearity of the transmission function and complexity of mechanical schema. A novel solution for the reel spool mechanism is proposed. Its kinematic schema and synthesis method are described. The kinematic schema of the chosen mechanism is based on a noncircular gear in series with a scotch-yoke mechanism. The yoke is driven by a stud fixed on the driving noncircular gear. The drawbacks of other models regarding the effects occurring at the ends of the spool are eliminated through achieving an appropriate transmission function of the spool. The linear function approximation with curved end-arches appropriately computed to ensure mathematical continuity is very good. The experimental results on the mechanism model validate the theoretical approach. The developed mechanism solution is recorded under a reel spool mechanism patent.

Study on the fitting ways of artificial neural networks

Function simulation,which is called virtual reality too,is popularly applied to solve uncertain problems.Good performance of hidden layers and perfect capability of function simulation make artificial neural networks one of the best choices to simulate functions with form unknown.Inputs and outputs were used to train the structure of the ar- tificial neural network to make the outputs of network vary with the given inputs and keep consistent with the original data within tolerance.However,we couldn't get expected re- sults by using samples of a simple two-variable-model for the cause of dimensional differ- ence.The way of artificial neural networks to fit functions,which uses 'multi-dimensional surface' of high dimension to fit 'multi-dimensional line' of low dimension,was proved;the conclusion that good effects of fitting don't mean good function modeling when a dimen- sional difference exists was provided,and a suggestion of 'surface collecting' in practical engineering application was proposed when collecting useful data.

A Note on the Solution of Water Wave Scattering Problem Involving Small Deformation on a Porous Channel-Bed

The solution of water wave scattering problem involving small deformation on a porous bed in a channel, where the upper surface is bounded above by an infinitely extent rigid horizontal surface, is studied here within the framework of linearized water wave theory. In such a situation, there exists only one mode of waves propagating on the porous surface. A simplified perturbation analysis, involving a small parameter ε （≤1） , which measures the smallness of the deformation, is employed to reduce the governing Boundary Value Problem （BVP） to a simpler BVP for the first-order correction of the potential function. The first-order potential function and, hence, the first-order reflection and transmission coefficients are obtained by the method based on Fourier transform technique as well as Green＇s integral theorem with the introduction of appropriate Green＇s function. Two special examples of bottom deformation： the exponentially damped deformation and the sinusoidal ripple bed, are considered to validate the results. For the particular example of a patch of sinusoidal ripples, the resonant interaction between the bed and the upper surface of the fluid is attained in the neighborhood of a singularity, when the ripples wavenumbers of the bottom deformation become approximately twice the components of the incident field wavenumber along the positive x -direction. Also, the main advantage of the present study is that the results for the values of reflection and transmission coefficients are found to satisfy the energy-balance relation almost accurately.

The V1 region of gp120 is preferentially selected during SIV/HIV transmission and is indispensable for envelope function and virus infection

A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted viruses that are preferentially selected have not been fully elucidated. Here, we analyzed amino acids changes in the envelope protein during simian immunodeficiency virus(SIV)/HIV deep transmission history and current HIV evolution within the last 15–20 years. Our results confirmed that the V1V2 region of gp120 protein, particularly V1, was preferentially selected. A shorter V1 region was preferred during transmission history, while during epidemic, HIV may evolve to an expanded V1 region gradually and thus escape immune recognition. We then constructed different HIV-1 V1 mutants using different HIV-1 subtypes to elucidate the role of the V1 region in envelope function. We found that the V1 region, although highly variable, was indispensable for virus entry and infection, probably because V1 deletion mutants exhibited impaired processing of gp160 into mature gp120 and gp41. Additionally, the V1 region affected Env incorporation. These results indicated that the V1 region played a critical role in HIV transmission and infection.