Large Amplitude Flexural Vibration of the Orthotropic Composite Plate Embedded with Shape Memory Alloy Fibers

AbstractThe free and forced vibration of large deformation composite plate embedded with shape memory alloy (SMA) fibers is investigated. A thermo-mechanical constitutive equation of SMA proposed by Brinson et al. is employed and the constitutive equations for evaluation of the properties of a hybrid SMA composite laminate are obtained. Based on the nonlinear theory of symmetrically laminated anisotropic plates, the governing equations of flexural vibration in terms of displacement and stress functions are derived. The Galerkin method has been used to convert the original partial differential equation into a nonlinear ordinary differential equation, which is then solved with harmonic balance method. The numerical results show that the relationship between nonlinear natural frequency ratio and temperature for the nonlinear plate has similar characteristics compared with that of the linear one, and the effects of temperature on forced response behavior during phase transformation from Martensite to Austenite are significant. The effects of the volume fraction of the SMA fiber, aspect ratio and free vibration amplitude on the dynamical behavior of the plate are also discussed

Improved Composite Gel Electrolyte by Layered Vermiculite for Quasi-Solid-State Dye-Sensitized Solar Cells

A composite quasisolid electrolyte is prepared by adding a layered vermiculite (VMT) into the iodide/triiodide electrolyte including 4-tert-butylpyridine, which obviously improves the photovoltaic properties of quasisolid dye-sensitized solar cells (DSSCs). When adding 6 wt% VMT, the maximum photovoltaic conversion efficiency of 3.89% is obtained, which reaches more than two times greater than that without VMT. This enhancement effect is primarily explained by studying the Nyquist spectra, dark currents, and photovoltaic conversion efficiency

The Antitumor Activities of Marsdenia tenacissima

Marsdenia tenacissima (MT), a traditional Chinese herbal medicine, has long been used for thousands of years to treat asthma, tracheitis, rheumatism, etc. An increasing number of recent studies have focused on the antitumor effects of MT. The effects of MT on cancer are the result of various activated signaling pathways and inhibiting factors and the high expression levels of regulatory proteins. MT can inhibit different cancer types including non-small cell lung cancer (NSCLC), malignant tumors, hepatic carcinoma, and so on. This article mainly focuses on the activities and mechanisms of MT. In addition, the efficacy and toxicity of MT are also discussed. Further studies of MT are required for improved medicinal utilization

Use of Radiomics Combined With Machine Learning Method in the Recurrence Patterns After Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: A Preliminary Study

Objective: To analyze the recurrence patterns and reasons in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) and to investigate the feasibility of radiomics for analysis of radioresistance.Methods: We analyzed 306 NPC patients treated with IMRT from Jul-2009 to Aug-2016, 20 of whom developed with recurrence. For the NPCs with recurrence, CT, MR, or PET/CT images of recurrent disease were registered with the primary planning CT for dosimetry analysis. The recurrences were defined as in-field, marginal or out-of-field, according to dose-volume histogram (DVH) of the recurrence volume. To explore the predictive power of radiomics for NPCs with in-field recurrences (NPC-IFR), 16 NPCs with non-progression disease (NPC-NPD) were used for comparison. For these NPC-IFRs and NPC-NPDs, 1117 radiomic features were quantified from the tumor region using pre-treatment spectral attenuated inversion-recovery T2-weighted (SPAIR T2W) magnetic resonance imaging (MRI). Intraclass correlation coefficients (ICC) and Pearson correlation coefficient (PCC) was calculated to identify influential feature subset. Kruskal-Wallis test and receiver operating characteristic (ROC) analysis were employed to assess the capability of each feature on NPC-IFR prediction. Principal component analysis (PCA) was performed for feature reduction. Artificial neural network (ANN), k-nearest neighbor (KNN), and support vector machine (SVM) models were trained and validated by using stratified 10-fold cross validation.Results: The median follow up was 26.5 (range 8–65) months. 9/20 (45%) occurred in the primary tumor, 8/20 (40%) occurred in regional lymph nodes, and 3/20 (15%) patients developed a primary and regional failure. Dosimetric and target volume analysis of the recurrence indicated that there were 18 in-field, and 1 marginal as well as 1 out-of-field recurrence. With pre-therapeutic SPAIR T2W MRI images available, 11 NPC-IFRs (11 of 18 NPC-IFRs who had available pre-therapeutic MRI) and 16 NPC-NPDs were subsequently employed for radiomic analysis. Results showed that NPC-IFRs vs. NPC-NPDs could be differentiated by 8 features (AUCs: 0.727–0.835). The classification models showed potential in prediction of NPC-IFR with higher accuracies (ANN: 0.812, KNN: 0.775, SVM: 0.732).Conclusion: In-field and high-dose region relapse were the main recurrence patterns which may be due to the radioresistance. After integration in the clinical workflow, radiomic analysis can be served as imaging biomarkers to facilitate early salvage for NPC patients who are at risk of in-field recurrence

An analytical model for shape memory alloy fiber-reinforced composite thin-walled beam undergoing large deflection

The structural model of the thin-walled laminated beams with integral shape memory alloy active fibers and accounting for geometrically nonlinear is presented in this article. The structural modeling is split into two parts: a two-dimensional analysis over the cross section and a geometrically nonlinear analysis of a beam along the beam span. The variational asymptotic method is used to formulate the force–deformation relationship equations taking into account the presence of active shape memory alloy fibers distributed along the cross section of the beam. The geometrically nonlinear governing equations are derived using variational principle and based on the von Kármán-type nonlinear strain–displacement relations. The equations are then solved using Galerkin’s method and an incremental Newton–Raphson method. The validation for the proposed model has been carried out by comparison of the present results with those available in the literature. The results show that significant extension, bending, and twisting coupled nonlinear deflections occur during the phase transformation due to shape memory alloy actuation. The effects of the volume fraction of the shape memory alloy fiber and ply angle are also addressed

Improved Composite Gel Electrolyte by Layered Vermiculite for Quasi-Solid-State Dye-Sensitized Solar Cells

A composite quasisolid electrolyte is prepared by adding a layered vermiculite (VMT) into the iodide/triiodide electrolyte including 4-tert-butylpyridine, which obviously improves the photovoltaic properties of quasisolid dye-sensitized solar cells (DSSCs). When adding 6 wt% VMT, the maximum photovoltaic conversion efficiency of 3.89% is obtained, which reaches more than two times greater than that without VMT. This enhancement effect is primarily explained by studying the Nyquist spectra, dark currents, and photovoltaic conversion efficiency

Mineralogical and geochemical study of apatite and dolomite from the Bayan Obo giant Fe-REE-Nb deposit in Inner Mongolia: New evidences for genesis

The Bayan Obo Fe-REE-Nb deposit is the world's largest resource of REE and its origin still remains controversial. To decipher the genesis of this unique deposit, we conducted a detailed mineralogical observations using scanning electron microscope (SEM), cathodoluminescence (CL) and in-situ micro-analyses on chemical compositions of the dolomite and apatite by EPMA and LA-ICPMS techniques. A wide range in SrO contents in dolomite mineral grains from coarse-grained dolomite marble has been observed. The SrO contents in the margin of the dolomite mineral reach up to 1.04 wt%, while the SrO contents in the core are as low as 0.16 wt%. In contrast, the SrO contents of the dolomite minerals of fine-grained dolomite marble are basically invariable, mainly concentrating on the range of 0.1 wt%-0.2 wt%. The MnO and FeO concentrations of dolomite mineral grains from the coarse-grained dolomite marble (MnO, 0.24 wt%-0.45 wt%; FeO, 2.27 wt%-3.42 wt%) are significantly lower than those of dolomite from fine-grained dolomite marble (MnO, 0.84 wt%-3.32 wt%; FeO, 3.59 wt%-12.16 wt%). The big differences in major elements between two types of the H8 dolomite marble imply different forming processes. Three types of apatite show big differences in cathodoluminescent signatures, major and trace elements. Type I fluorapatite has few REE mineral inclusions and Type II fluorapatite hosts abundant tiny REE mineral (monazite) inclusions. Type III fluorapatite from strongly deformed coarse-grained dolomite marble forms abnormally large monocrystals with elongated orientation. Both Type I and Type II fluorapatite from fine-grained dolomite marble samples display the heterogeneous component regions under BSE, with obvious depletion in Na and REE in BSE-dark areas observed in the X-ray compositional maps. Unaltered (BSE-bright) regions in Type I and Type II fluorapatite have high REE (17470-77090 ppm), Y (714-8162 ppm), Na (2023-10258 ppm), Sr (2126-6422 ppm) concentrations, obviously different from Type III fluorapatite (REE, 2452-7496 ppm; Y, 157-285 ppm; Na, 501-1464 ppm; Sr, 6878-9949 ppm). The REE, Na, Th and Pb depletion in BSE-dark regions in Type I and Type II apatite correspond to two styles of REE re mobilization during fluid-induced dissolution-reprecipitation processes. Late-stage REE, Na, Ba, CO32-, SO42- rich mesothermal hydrothermal fluid evolved from carbonatite was responsible for REE leaching in Type I fluorapatite. The Sr-rich, Na-poor, REE-poor Type III fluorapatite and associated elevated SrO contents in the margin of dolomite imply that the deposit underwent subsequent fluid infiltration by Sr-rich, REE-poor, Na-poor metamorphic fluid, causing the REE leaching in Type II fluorapatite and the consequent formation of monazite inclusions. As a common REE-bearing mineral in Bayan Obo deposit, apatite displays a diversity of textures and occurrences, fingerprints multi-stage metasomatic fluids and provides new insights into the mechanism of REE enrichment and remobilization

Enhanced Photovoltaic Properties of the Solar Cells Based on Cosensitization of CdS and Hydrogenation

The hydrogenated TiO2 porous nanocrystalline film is modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR) method to prepare the cosensitized TiO2 solar cells by CdS quantum dots and hydrogenation. The structure and topography of the composite photoanode film were confirmed by X-ray diffraction and scanning electron microscopy. With deposited CdS nanoparticles, UV absorption spectra of H:TiO2 photoanode film indicated a considerably enhanced absorption in the visible region. The cosensitized TiO2 solar cell by CdS quantum dots and hydrogenation presents much better photovoltaic properties than either CdS sensitized TiO2 solar cells or hydrogenated TiO2 solar cells, which displays enhanced photovoltaic performance with power conversion efficiency (η) of 1.99% (Jsc=6.26 mA cm−2, Voc=0.65 V, and FF = 0.49) under full one-sun illumination. The reason for the enhanced photovoltaic performance of the novel cosensitized solar cell is primarily explained by studying the Nyquist spectrums, IPCE spectra, dark current, and photovoltaic performances