An analytical modeling method of hard-coating laminated plate under base excitation was studied considering strain-dependent characteristic of coating material (i.e. a kind of material nonlinear behavior). For convenience, the strain-dependent characteristic of hard-coating material was characterized by polynomial, and the material parameters were divided into two parts: linearity and nonlinearity. Hard coating was regarded as a special layer in the analysis and Lagrange’s equation was used to acquire nonlinear equation of motion of the hard-coating laminated plate. Based on Newton–Raphson method, the procedure of solving resonant response and resonant frequency of composite plate was presented. Finally, a T300/QY89l1 laminated plate with NiCoCrAlY + YSZ hard coating was chosen to demonstrate the proposed method, the linear and nonlinear vibrations of the composite plate were solved, and only the linear results were validated by ANSYS software. The results reveal that there is a big difference between the calculation results considering the nonlinearity of coating material and the linear results, which means the laminated plate displays soft nonlinear phenomenon because of depositing coating.
Manipulation of radiation pattern control is challenging, especially at low frequencies. In this paper, we demonstrate that acoustic metamaterials as an effective array of quadrupoles can remarkably improve the directionality of acoustic radiation at low frequencies, compared with previous metamaterials as monopole and dipole structures. The directivity of the acoustic radiation can be adjusted by changing the characteristic parameter and the symmetry of the structure, which provide a flexible method of adjustable radiation di-rections. The directionality can be further improved by constructing linear array of structure. Our work opens an approach of acoustic radiation control via quadrupolar metamaterials.
We investigate a one-dimensional acoustic metamaterial with a refractive index of near zero (RINZ) using an array of very thin elastic membranes located along a narrow waveguide pipe. The characteristics of the effective density, refractive index, and phase velocity of the metamaterial indicate that, at the resonant frequency , the metamaterial has zero mass density and a phase transmission that is nearly uniform. We present a mechanism for dramatic acoustic energy squeezing and anomalous acoustic transmission by connecting the metamaterial to a normal waveguide with a larger cross-section. It is shown that at a specific frequency f 1, transmission enhancement and energy squeezing are achieved despite the strong geometrical mismatch between the metamaterial and the normal waveguide. Moreover, to confirm the energy transfer properties, the acoustic pressure distribution, acoustic wave reflection coefficient, and energy transmission coefficient are also calculated. These results prove that the RINZ metamaterial provides a new design method for acoustic energy squeezing, super coupling, wave front transformation, and acoustic wave filtering.
The Sm doped cerium dioxide films were prepared with cerium foils as raw materials by anodization in Sm(NO3)3-Na2C2O4-NH3·H2O-H2O-(CH2OH)2 electrolyte. The anodic Sm doped cerium oxide films were heat treated in 100°C ~ 400°C. The heat treated anodic Sm doped cerium oxide films were characterized with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques respectively. The heat treated anodic Sm doped cerium oxide film at 100°C is the semi crystalline film. As heat treatment temperatures being in 200°C ~ 400°C, the heat treated anodic Sm doped cerium oxide films have a structure of cubic fluorite respectively. The doping of Sm can be achieved well by anodization method and be recognized as replacement doping or caulking doping. The crystal structure of Sm doped cerium dioxide films become more complete with the increase of heat treatment temperature in 200 ~ 400 °C. The doping of Sm can improve the crystallinity of the cerium dioxide film. The presence of adsorbing water, ethylene glycol and CO2 in the heat treated anodic Sm doped cerium oxide film at 100°C. The adsorbing ethylene glycols and water, CO2 in the anodic Sm doped cerium oxide film are removed at 200°C and 300°C respectively.
Ewing's sarcoma is a kind of bone and soft tissue tumor which is highly invasive and mainly occurres in chil-dren and adolescents. In recent years, combined chemotherapy, surgery and radiation therapy in treatment of Ewing's sarcoma, pa-tients’ prognosis and life quality have been significantly improved. However, over the past 20 years, the treatment of Ewing's sar-coma entered the platform period. The 5-year overall survival rate remained at 55%-75%. Multiple metastasis and recurrence are the main factors of poor prognosis and death. Chemotherapy, radiotherapy and molecular targeted therapy are still the main meth-ods for the treatment of Ewing sarcoma. The side effects, drug resistance and the use of the combination regimen of antitumor drugs have been plaguing the clinical workers. In order to improve the efficacy of chemotherapy drugs and reduce the toxic side ef-fects, Multi-disciplinary and multi-center clinical studies on Ewing's sarcoma patients who suffered from local control or recur-rence have been launched by Domestic and European and American countries. As an important supplementary mean for the treat-ment of Ewing's sarcoma, patients often appear a series of complications after radiotherapy, including the risk of local damage or secondary tumors. Therefore, it is necessary to further clarify the indications of radiotherapy and the timing of preoperative and postoperative radiotherapy. The specific chromosome translocation and the expression of the fusion gene EWS/FLI1 have been found in Ewing sarcoma. Nevertheless, the mechanisms that drive tumor relapse and metastasis remain unknown. Molecular target-ed therapy can be used to inhibit tumorigenesis and progression by regulating the upstream or downstream target genes of EWS/FLI1. In conclusion understanding of the current treatment status of Ewing's sarcoma, results of multi-center clinical trials and the-ory of genomics research will contribute to the design of new biological therapies so as to establish individualized treatment modali-ties. In this paper, we present a review on the progress of Ewing sarcoma chemotherapy, radiotherapy, molecular targeted therapy and immunotherapy.
Based on the study of fracture toughness II of frozen soil, the application of fracture toughness II is firstly used in undisturbed frozen soil in this paper. Because of undisturbed soil not vibrated and microstructures inside of the soil body not change, it is more realistic and more meaningful than remolded soil in laboratory. In the research, bend test stand was improved at first time, and drawing on prefabricated vertical cracks in rock fracture test to observe the cracks size by coloring. With the observations on layering frost heave of the local soil, the relations of frost heave, melt and time are obtained in different deep soil layers, so that the samples production and test temperature can be controlled strictly. The fracture toughness of four-point-bending vertical pre-cracked specimens of test II of undisturbed frozen soil is obtained. Experimental results indicate that the undisturbed frozen soil mechanics experiment is completely available, and it is feasible to measure the crack size with coloring technology, the fracture toughness II of undisturbed frozen soil is also obtained.
Manipulating radiation patterns is challenging, especially at low frequencies. In this paper, we demonstrate that acoustic metamaterials arranged as an array of quadrupoles remarkably improve the directionality of acoustic radiation at low frequencies, compared with previous metamaterials arranged as monopole and dipole structures. The directivity of the acoustic radiation can be adjusted by changing the characteristic parameter and the symmetry of the structure, which provides a flexible method of adjusting radiation directions. The directionality can be further improved by constructing a linear array. Our work establishes acoustic radiation control via quadrupolar metamaterials.
A novel design of a configurable dual-band EBG (Electromagnetic Bandgap) bandpass filter is proposed. The EBG filter is manufactured by a conventional 2-layer PCB process in RO4350 substrate with surface mounted lumped capacitors. Specific working frequency of each band of the filter can be selected on demand by adjusting the value of corresponding capacitors, while the filter's performance and compact design is not compromised. The experimental results show a filter with size of 28.00 × 28.00 × 1.52 mm3 in PCB achieving performance of insertion loss of 2.18 dB, 2.24 dB; return loss of 14.5 dB, 11.3 dB at 2.30 GHz, 4.1 GHz respectively. The filter has band to band isolation better than 48.0 dB and spurious free region up to 9.00 GHz.
To design and optimize seismic metamaterials, the impacts of nonlinearity in different locations of locally resonant acoustic metamaterials on the dispersions and the variation of amplitude-dependent bandgaps are investigated in this paper. The research used theoretical calculations, namely, Lindstedt–Poincaré perturbation method and prediction method, and combined finite-element simulation. Summarizing from our research, the lower bandgap is sensitive when exposed to amplitude stimulation, when there arise nonlinear characteristics between matrices; while nonlinearity appears within the interior oscillator, amplitudes obtain a more intense influence on the bandgap, introducing an enormous magnitude of deviation between the upper bandgap and the lower bandgap. Based on the peculiar frequency-shift characteristics, an acoustic three-terminal controller is proposed as a conventional subsize acoustical device and nonlinear seismic metamaterials component. This controller enables the realization of modulating the value of output signals by adjusting the quantitative loading on the control port, without changing the input signals and the parameters of the apparatus validated with the finite-element simulation. The work may offer potential applications in low-frequency vibration reduction and external-controllable multi-functional acoustical devices.
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