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Li 2 TiO 3 -based materials are gaining momentum in the field of microwave dielectric ceramics for their moderate dielectric constant and high-quality factor. Herein, a novel oxyfluoride ceramic Li 3 TiO 3 F in the Li 2 TiO 3 –LiF system was successfully prepared by a traditional ceramic method. The synthesis process of Li 3 TiO 3 F ceramic was optimized to obtain improved microstructure and desired microwave dielectric properties (MDP) by means of material characterization techniques, such as thermogravimetric-differential thermal analysis, X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. A cubic rock salt structure for Li 3 TiO 3 F ceramic was confirmed by Rietveld refinement results. The ceramic sintered at 900 °C showed the most favorable MDP of ε r = 17.28, quality factor (Q × f) = 96,280 GHz, and τ f = −32.7 ppm/°C, obtaining a microstructure superior to that of Li 2 TiO 3. Moreover, the ceramic exhibited favorable chemical compatibility with Ag at 900 °C, indicating a great potential for the use of Li 3 TiO 3 F ceramic as substrates in low temperature cofired ceramic (LTCC) technology. More importantly, the results of this work offered the option of using low temperature firing of ceramic by forming a solid solution between the oxide and the fluoride. [ABSTRACT FROM AUTHOR]

In this paper, a series of Li 2 Zn[Ti 1- x (Co 1/3 Nb 2/3) x ] 3 O 8 (0.0 ≤ x ≤ 0.4) ceramics were prepared via the conventional solid-state method. The influences of (Co 1/3 Nb 2/3)4+ complex ions on the phase composition, spectral characteristics, microstructure, and microwave dielectric properties of Li 2 Zn[Ti 1- x (Co 1/3 Nb 2/3) x ] 3 O 8 ceramics were studied systematically. XRD analysis accompanied with Rietveld refinements showed that pure Li 2 ZnTi 3 O 8 solid solution ceramics with the cubic spinel structure were obtained at x = 0.2–0.4. New Raman-active mode of about 858 cm−1 should be attributed to the vibrations of NbO 6 due to the high bond energy of Nb–O bonds, exerting a certain impact on the structure and performance of Li 2 Zn[Ti 1- x (Co 1/3 Nb 2/3) x ] 3 O 8 ceramics. XPS results indicated that Nb5+ ion donor suppressed the deoxidation process and therefore resulted in the disappearance of Ti3+ ion and oxygen vacancy. The downward trend variation in the ε r value with the increase of (Co 1/3 Nb 2/3)4+ content could be explained by the presence of "compressed" cations and "rattling" cations effect. In addition, the Q × f of the current ceramics was closely dependent on relative density, grain size, FWHM, and oxygen vacancy. Good combined microwave dielectric properties of ε r = 24.5, Q × f = 91,250 GHz, and τ f = −16.8 ppm/°C were achieved for the Li 2 Zn[Ti 0.8 (Co 1/3 Nb 2/3) 0.2 ] 3 O 8 ceramic sintered at 1120 °C. High quality factor gives evidence that the Li 2 Zn[Ti 0.8 (Co 1/3 Nb 2/3) 0.2 ] 3 O 8 ceramic is an appealing candidate for highly selective microwave devices. [ABSTRACT FROM AUTHOR]

In this study, LiF was utilized to decrease sintering temperature, improve microstructure, enhance Q × f , and regulate τ f of Li 2 Ti 0.9 (Zn 1/3 Ta 2/3) 0.1 O 3 (abbreviated as LTZT) ceramics. A complete solid solution together with a phase transition from monoclinic to cubic rock salt structure occurred. The cell volume of LTZT ceramics decreased as the LiF content increased. Relatively dense and uniform microstructures were observed for the ceramics as the LiF content was not less than 2 wt%. The dielectric constant of LTZT ceramics initially increased and then decreased with the increasing LiF content. The FWHM of the Raman band at about 808 cm−1 was closely related to the Q × f value. Notably, the samples with 3 wt% LiF exhibited the highest relative density of 97.4 % and satisfactory microwave dielectric properties of ε r = 23.14 ± 0.16, Q × f = 110,090 ± 1100 GHz, and τ f = +3.25 ± 1.45 ppm/°C when sintered at 950 °C. Good chemical compatibility with silver indicated the ceramic is a promising candidate in LTCC applications. [ABSTRACT FROM AUTHOR]

The lack of observed sausage perturbations in solar active region loops is customarily attributed to the relevance of cutoff axial wavenumbers and the consequent absence of trapped modes (called "evanescent eigenmodes" here). However, some recent eigenvalue problem studies suggest that cutoff wavenumbers may disappear for those equilibria where the external density varies sufficiently slowly, thereby casting doubt on the rarity of candidate sausage perturbations. We examine the responses of straight, transversely structured coronal slabs to small-amplitude sausage-type perturbations that excite axial fundamentals, by solving the pertinent initial value problem with eigensolutions for a closed domain. The density variation in the slab exterior is dictated by some steepness parameter μ, and cutoff wavenumbers are theoretically expected to be present (absent) when μ ≥ 2 (μ < 2). However, our numerical results show no qualitative difference in the system evolution when μ varies, despite the differences in the modal behavior. Only oscillatory eigenmodes are permitted when μ ≥ 2. Our discrete eigenspectrum becomes increasingly closely spaced when the domain broadens, and an oscillatory continuum results for a truly open system. Oscillatory eigenmodes remain allowed and dominate the system evolution when μ < 2. We show that the irrelevance of cutoff wavenumbers does not mean that all fast waves are evanescent. Rather, it means that an increasing number of evanescent eigenmodes emerge when the domain size increases. We conclude that sausage perturbations remain difficult to detect, even for the waveguide formulated here. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing in combination with horizontal well has been widely used to stimulate shale oil and gas from reservoirs. Numerical simulation of hydraulic fracturing is a great challenge due to the geological complexity of reservoirs. In this paper, a fully coupled fluid flow, plastic deformation and fracture propagation model is presented based on cohesive zone method. An implicit algorithm to discretize and integrate the fully coupled differential equations is presented. Plastic deformation is observed in the vicinity of hydraulic fracture during the stimulation process. The effect of plastic and stimulation parameters on fracture propagation behaviors has been investigated. The energy dissipation induced by the plastic deformation increases the fracture width. The fracture propagation behaviors both in viscosity and toughness dominated regimes are discussed. The evolution formula of non-dimensional fracture length at different regimes is presented by fitting numerical results. [ABSTRACT FROM AUTHOR]

In this paper, nanocrystalline Nd[(Zn0.925Co0.075)1/2Ti1/2]O3 (NZCT75) powders were synthesized through glycine–nitrate combustion method with the intent of reducing the sintering temperature and improving the microwave dielectric properties of NZCT75 ceramics. Phase composition, structure, and morphology of the powders were analyzed by thermogravimetric analysis–differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD results showed that the as-synthesized powder after rapid self-propagating combustion was highly crystallized and was mainly composed of NZCT75 phase and small amount of unknown phase. The unknown phase could be vanished through the calcination process of 600 °C. Compared to solid-state reaction route, a reduction of about 600 °C in the synthesis temperature for pure phase NZCT75 was realized. A large amount of pores with inhomogeneous distribution in size and shape was found from the SEM image of the as-synthesized powder due to the rapid combustion reaction between glycine and nitrates. The TEM study revealed that the average particle size of the calcined powder is around 31.9 nm. The bulk sample prepared by the nanosized powder could be sintered to 98.8% of the theoretical density at 1250 °C, reducing about 160 °C more than the solid-state reaction method. Meanwhile, excellent microwave dielectric properties of NZCT75 ceramics presented a dielectric constant of 37.17, a quality factor of 257,600 GHz, and a temperature coefficient of resonant frequency of – 29.48 ppm/oC. This study develops a facile approach to synthesize nanocrystalline powder for a promising application in microwave dielectric ceramics. [ABSTRACT FROM AUTHOR]

Gesture recognition plays an important role in smart homes, such as human–computer interaction, identity authentication, etc. Most of the existing WiFi signal-based approaches exploit a large number of channel state information (CSI) datasets to train a gestures classification model; however, these models require a large number of human participants to train, and are not robust to the recognition environment. To address this problem, we propose a WiFi signal-based gesture recognition system with matched averaging federated learning (WiMA). Since there are differences in the distribution of WiFi signal changes caused by the same gesture in different environments, the traditional federated parameter average algorithm seriously affects the recognition accuracy of the model. In WiMA, we exploit the neuron arrangement invariance of neural networks in parameter aggregation, which can improve the robustness of the gesture recognition model with heterogeneous CSI data of different training environments. We carried out experiments with seven participant users in a distributed gesture recognition environment. Experimental results show that the average accuracy of our proposed system is up to 90.4 % , which is very close to the accuracy of state-of-the-art approaches with centralized training models. [ABSTRACT FROM AUTHOR]

Predicting the trajectories of hydraulic fractures in unconventional reservoirs poses a significant challenge due to the heterogeneous nature of the rock matrix. Obtaining an accurate distribution of rock properties from limited measurements of rock samples near wellbores is difficult. In this study, we propose a deep learning framework that utilizes observations of hydraulic fracture patterns to identify nonuniform distributions of rock properties. Our approach utilizes the deep operator network (DeepONet) to map elastic properties to fracture geometries, and establishes an inverse problem to map fracture geometries back to elastic properties. Our results demonstrate a high level of accuracy in predicting nonplanar paths of single and multiple hydraulic fractures in heterogeneous formations. The well-trained model can rapidly evaluate numerous fracture patterns within seconds, surpassing the efficiency of finite element-based methods. Furthermore, fracture trajectories enable the identification of nonuniform distributions of rock properties. The maximum point-wise error of predicted Young's modulus compared to the ground truth is less than 20 %, with accurate identification of distribution patterns. Only a few regions exhibit relatively large errors, approaching 20 %. The presented approach provides valuable insights for the identification of reservoir properties in engineering applications. [Display omitted] • A deep learning surrogate model to predict nonplanar fracture trajectories in heterogenous formation is established. • Nonuniform distributions of Young's modulus can be identified using fractures data. • The approach presented here has the potential to identify other rock mechanical properties. • The well-trained model outperforms conventional numerical methods in terms of computational efficiency. [ABSTRACT FROM AUTHOR]

Background and Objective: Ramucirumab is a novel antiangiogenic agent approved as second-line therapy for patients with advanced stomach cancer and gastroesophageal junction adenocarcinoma. Although existing evidence from clinical trials has demonstrated hypertension is one of the major adverse events of this agent, overall risks have yet to be reported. Methods: We carried out a meta-analysis of published studies to determine the overall incidence and relative risk (RR) of hypertension associated with ramucirumab. Statistical analyses were conducted to calculate the summary incidence, RRs, and 95 % confidence intervals (CIs) by using a random effects model. Results: Eleven studies with a total of 3,851 patients with multiple cancers were included. The overall incidence of all-grade hypertension was 20.0 % (95 % CI 15.0-26.0) with 8.6 % (95 % CI 6.3-11.7) being high-grade hypertension. The risk of developing hypertension was greater in ramucirumab-treated patients (RR for all grades 2.77, 95 % CI 1.94-3.94, p < 0.001, RR for high-grade 3.58, 95 % CI 2.45-5.23, p < 0.001). Conclusions: Administration of ramucirumab to patients with cancer is associated with increased risk of hypertension. [ABSTRACT FROM AUTHOR]

The laboratory performance and modification mechanism of asphalt modified with Sasobit and Polyphosphoric acid (PPA) were studied through a comprehensive laboratory program. The base asphalt was mixed with 3% Sasobit to produce Warm Mix Asphalt (WMA) and then modified with four different percentages of PPA (0.5%, 1.0%, 1.5% and 2.0%) by mass of base asphalt, respectively. The rolling thin film oven (RTFO) and the pressure aging vessel (PAV) procedures were conducted to simulate the aging of asphalt. Experiments were conducted for asphalts under different aging conditions. The rheological property of asphalt was measured by conventional tests, the Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). The morphological characteristic of asphalt was evaluated by Fourier Transform Infrared Spectroscopy (FT-IR), Fluorescence microscopy, Thermogravimetric (TG) and Differential Scanning Calorimetry (DSC). It is concluded that the rheological properties of asphalts were enhanced after Sasobit and PPA were added. The penetration of asphalts decreased and softening point increased, proving that deformation resistance was enhanced and high-temperature stability improved. The ductility decreased to an acceptable level when the PPA content was less than 1.0%. High-temperature deformation resistance and aging resistance were enhanced for asphalts under different aging conditions. In order to guarantee the low-temperature property of asphalt, PPA content in WMA should be no more than 1.5%. The modification effect of Sasobit and PPA on asphalt included chemical and physical processes. The compatibility between PPA, Sasobit and base asphalt is good and the microstructure of the modified asphalt is beneficial in improving the performance of asphalt. The addition of Sasobit restricted the decomposition process of the asphalt component, and the addition of PPA further alleviated the decomposition process and enhanced the stability of asphalt. [ABSTRACT FROM AUTHOR]

Well-aligned PMIA nanofiber mats were fabricated by electrospinning and then hot-pressing was used to produce PMIA nanofiber mats reinforced PLA matrix by layer-by-layer with the interlayer angles of 0, 45, and 90°. Orthogonal experimental design was employed to fix the effect of the hot-pressing parameters on the tensile strength of nanocomposites, and SEM was used to characterize the broken sections of the nanocomposites after tensile test. The optimized process parameters were achieved of pressure as 1000 Pa, temperature as 180°C, and time as 30 min. The SEM images of broken sections showed that the different laminate forms and the state of bearing load of nanofibers resulted in the different morphologies of broken sections. The break strength of PMIA/PLA nanocomposites with any of interlayer angles at different tensile testing directions was revealed as follows: axial > oblique > transverse, and the initial modulus also showed the same except the angle of 90° with the approach initial modulus at the axial and transverse directions. The maximum tensile strength and modulus of the nanocomposites were 17.12 MPa and 1642.17 MPa, respectively, of the axial tensile testing directions of the interlayer angle of 0°. [ABSTRACT FROM AUTHOR]

In this study, the objective was to conduct a laboratory investigation of rheological and morphological properties of warm mix asphalt containing polyphosphoric acid (WMA-PPA). The Superpave binder tests (i.e., rotational viscosity test, dynamic shear rheometer (DSR) test and bending beam rheometer (BBR) test) as well as microscopic tests (i.e., Fluorescence microscopy, Fourier transform infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry and Thermogravimetry (DSC/TG) test) were performed to determine the influences of polyphosphoric acid (PPA) on warm mix asphalt binders. The experimental design included six binders and four different polyphosphoric acid dosages (by weigh of neat asphalt). The test results indicated that, the addition of PPA into warm mix asphalt binders exhibited an increase in the viscosity at different test temperatures, giving clear indication of the modification effects of PPA on the warm mix asphalt binders’ high-temperature performances. Temperature and frequency sweep tests show that the WMA-PPA binders demonstrate lower value of phase angle and higher value of complex modulus compared with the WMA binder regardless of aging state, the WMA-PPA asphalt containing more PPA has higher values of complex modulus (lower values of phase angle) than the WMA-PPA asphalt with less PPA in original state and after RTFO aging state. Bending beam rheometer (BBR) test illustrates that the addition of PPA making the low temperature rheological properties of the WMA binder worse. Furthermore, the amount of PPA has a great effect on the microstructures and hot storage stability of WMA-PPA asphalts, and the modification effect of PPA on WMA asphalt is a chemistry process. The 1.5% of PPA was found to be the optimum content between the studied percentages due to the warm mix asphalt binder containing 1.5% PPA achieved comparative good intermediate and high temperature rheological properties and at the same time is considered economical. [ABSTRACT FROM AUTHOR]

Background: The role of insulin in the pathogenesis of cancer has been increasingly emphasized because of the high incidence of obesity and metabolic syndrome and their correlated complication including cancer. This study aimed to explore the impact of insulin on chemoresistance to 5-fluorouracil in gastric cancer and the possible mechanisms. Methods: Tissue samples of gastric cancer and adjacent normal gastric mucosa from patients with or without obesity were performed immunohistochemical staining for P-glycoprotein. The follow-up was done after the surgical treatment. The effect of insulin on chemotherapeutic sensitivity of the three gastric cancer cell lines to 5-fluorouracil was evaluated by pre-incubation with insulin before administration of 5-fluorouracil. The expression of P-glycoprotein was determined by Western blotting. Results: P-glycoprotein were overexpressed in tissues from patients who suffered gastric cancer and were higher in those simultaneously suffered gastric cancer and obesity. Addition of 1 μM insulin remarkably promoted the proliferation of SGC7901, MKN45 and MKN28 cells and decreased the cytotoxicity of 5-fluorouracil. In addition, the expression of P-glycoprotein was upregulated in SGC7901, MKN45 and MKN28 cells. Conclusion: Insulin improved the proliferation of gastric cancer cell lines and contributed to chemoresistance of gastric cancer cells to 5-fluorouracil which is likely to involve upregulation of P-glycoprotein. [ABSTRACT FROM AUTHOR]