1,061 research outputs found

    Analytical analysis for horizontal displacement of pile anchor support structure considering prestress

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    The pile-anchor supporting structure is widely used in foundation pit engineering, it is particularly necessary for calculating lateral displacement of the pile-anchor supporting structure. The soil stress state is transformed by the additional stress caused by the prestress, thus the lateral displacement can be decreased own to pile-anchor supporting structure bearing active earth pressure had changed. Prestress as a concentrated force is decomposed into the horizontal component and vertical component, calculating the additional stress caused by the prestress and getting the formula of active earth pressure of considering the additional stress, setting up calculation model of the pile-anchor supporting structure. For typical examples of foundation pit engineering, the parameters are substituted into a program written based on derived formulas, and the elastic deformation superposition method is used to calculate the horizontal displacement of the pile anchor support structure. The comparison and verification is carried out by Finite element analysis. The influence of cohesion and friction angle on pile displacement, bending moment, and shear force has been studied. This study found that cohesion and friction angle have a significant impact on the displacement of pile anchor support structures

    Investigation on Microstructure and Optical Property of Nanocrystalline Silicon Thin Film

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    Nanocrystalline silicon (nc-Si:H) thin films were deposited by capacitive coupled radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) system with direct current (DC) bias applied. Raman, XRD and ultraviolet-visible transmission spectra were employed to investigate their microstructure and optical properties, respectively. Both the crystalline volume fraction and the average crystalline size increase with the substrate temperature. With the increase of silane concentration, the crystalline volume fraction increases, while the average crystalline size decreases. With the increase of the radio frequency (RF) power or the DC negative bias voltage, the crystalline volume fraction and the average crystalline size increase firstly, then decreases. Finally, the optical band gaps were discussed in detail

    Ultrahigh Sensitivity Temperature Sensor Based on Harmonic Vernier Effect

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    A high-sensitivity and miniature open cavity Fabry–Perot interferometer (OCFPI) encapsulated with the polydimethylsiloxane (PDMS) film based on high-order harmonic Vernier effect is designed and experimentally investigated. To the best of our knowledge, PDMS is applied for the first time to fill the open cavity of Fabry–Perot interferometer to obtain high-temperature sensitivity. The resonant dip (peak) wavelength of the designed temperature sensor monotonically moves toward the shortwave direction as the temperature increases from 40°C to 60°C due to the effects of expansion and thermo–optic property of PDMS. The proposed OCFPI encapsulated with PDMS film provides the following excellent performance advantages. (1) Compared with traditional all-fiber air-cavity OCFPIs with temperature sensitivity of approximately 10 pm/°C, the proposed OCFPI sensor has a much higher temperature sensitivity of -3.4 nm/°C at the temperature range of 40°C–60°C with a magnification factor ( M -factor) of approximately 11 when order of harmonic Vernier effect i = 4. (2) The proposed OCFPI exhibits good reversibility during the heating and cooling processes, and the measured M -factor matches well with the theoretically calculated M -factor. (3) The proposed OCFPI shows excellent stability with maximum wavelength deviation of 0.567 nm (internal envelope based on a fourth-order harmonic Vernier effect) and 0.042 nm (upper envelope) within 450 min. (4) The proposed OCFPI is inexpensive, robust, easy to fabricate, and compact, which can be used in harsh environments. Therefore, it provides excellent potential in dynamic temperature measurement

    Antibiotic Resistomes in Plant Microbiomes

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    Microorganisms associated with plants may alter the traits of the human microbiome important for human health, but this alteration has largely been overlooked. The plant microbiome is an interface between plants and the environment, and provides many ecosystem functions such as improving nutrient uptake and protecting against biotic and abiotic stress. The plant microbiome also represents a major pathway by which humans are exposed to microbes and genes consumed with food, such as pathogenic bacteria, antibiotic-resistant bacteria, and antibiotic-resistance genes. In this review we highlight the main findings on the composition and function of the plant microbiome, and underline the potential of plant microbiomes in the dissemination of antibiotic resistance via food consumption or direct contact

    5-(4-Fluoro­phen­yl)-2-furylmethyl N-(2,6-difluoro­benzo­yl)carbamate

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    The title compound, C19H12F3NO4, was synthesized by the reaction of 5-(4-fluoro­phen­yl)-2-furan­methanol and 2,6-difluoro­benzoyl­isocyanate. The seven atoms of the fluorophenyl group are disordered over two positions with site occupancy factors ca 0.6 and 0.4. The dihedral angle between the furan and fluorophenyl rings is 1.58°. In the crystal structure, the mol­ecules are linked via inter­molecular N—H⋯O hydrogen bonds to form chains

    Uptake and transport of a novel anticancer drug-delivery system: lactosyl-norcantharidin-associated N-trimethyl chitosan nanoparticles across intestinal Caco-2 cell monolayers

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    In this paper, novel liver-targeting nanoparticles (NPs), lactosyl-norcantharidin (Lac-NCTD)-associated N-trimethyl chitosan (TMC) NPs (Lac-NCTD-TMC-NPs), were prepared using ionic cross-linkage. The physical properties, particle size, and encapsulation efficiency of the nanoparticles were then investigated. The continuous line of heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2) cell monolayer model was used to study the transport mechanism of Lac-NCTD, and the effects of factors such as time, temperature, pH level, drug concentration, enhancers, and inhibitors. This model was also used to indicate the differences among Lac-NCTD, Lac-NCTD-associated chitosan NPs (Lac-NCTD-CS-NPs), and Lac-NCTD-TMC- NPs in the absorption and transportation of membranes. Drug concentration levels were measured using high-performance liquid chromatography. Active transport and paracellular transport were suggested to be both the primary and secondary mechanisms for Lac-NCTD absorption, respectively. Lac-NCTD uptake and absorption were not controlled by pH levels, but were positively correlated to uptake time, and negatively correlated to temperature. The basolateral to apical apparent permeability coefficients (Papps) were higher than those of the apical to basolateral values. The inhibitor of P-glycoprotein and the multidrug resistance-associated protein 2 significantly enhanced the uptake amount of Lac-NCTD. Compared with Lac-NCTD, Lac-NCTD-CS-NPs and Lac-NCTD-TMC-NPs significantly enhanced drug absorption. Additionally, the latter exhibited stronger action. Lac-NCTD-NPs could penetrate the plasma membrane of Caco-2 cells and translocate into the cytoplasm and even into the nucleus. Nanoparticles were uptaken into Caco-2 cells through the endocytosis pathway

    Synthesis, Biological Evaluation, and Molecular Docking Studies of Hydrazones as Novel Xanthine Oxidase Inhibitors

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    A series of hydrazones, 2-cyano-N'-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide (1), N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)-3-chlorobenzohydrazide monohydrate (2·H2O), N'-(2-hydroxy-3-methylbenzylidene)-4-nitrobenzohydrazide (3), and N'-(2-hydroxy-3-trifluoromethoxybenzylidene)-4-nitrobenzohydrazide (4), were prepared and structurally characterized by elemental analysis, IR and 1H NMR spectra, and single crystal X-ray determination. Xanthine oxidase inhibitory activities of the compounds were studied. Among the compounds, 2-cyano-N’-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide shows the most effective activity. Docking simulation was performed to insert the compounds into the crystal structure of xanthine oxidase at the active site to investigate the probable binding modes
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