Research on Fault Parameters Modeling Approach of Aircraft IDG

The essence of the faults of the aircraft IDG (Integrated Drive Generator) is the change of its internal structure parameters. In this paper, mathematical models of the exciter and the main generator in aircraft IDG are constructed and the relationship between the parameter change and the faults can be observed directly through the mathematical models. The mathematical models are simulated in MATLAB/Simulink. After modifying certain fault parameters, the relevant fault waveform of aircraft IDG can be acquired

Photocatalytic abstraction of hydrogen atoms from water using hydroxylated graphitic carbon nitride for hydrogenative coupling reactions

Employing pure water, the ultimate green source of hydrogen donor to initiate chemical reactions that involve a hydrogen atom transfer (HAT) step is fascinating but challenging due to its large H−O bond dissociation energy (BDEH-O=5.1 eV). Many approaches have been explored to stimulate water for hydrogenative reactions, but the efficiency and productivity still require significant enhancement. Here, we show that the surface hydroxylated graphitic carbon nitride (gCN−OH) only requires 2.25 eV to activate H−O bonds in water, enabling abstraction of hydrogen atoms via dehydrogenation of pure water into hydrogen peroxide under visible light irradiation. The gCN−OH presents a stable catalytic performance for hydrogenative N−N coupling, pinacol-type coupling and dehalogenative C−C coupling, all with high yield and efficiency, even under solar radiation, featuring extensive impacts in using renewable energy for a cleaner process in dye, electronic, and pharmaceutical industries

An Investigation into the Cytotoxic Effects of 13-Acetoxysarcocrassolide from the Soft Coral Sarcophyton crassocaule on Bladder Cancer Cells

Active compounds from natural products have been widely studied. The anti-tumor effects of 13-acetoxysarcocrassolide isolated from Formosan soft coral Sarcophyton crassocaule on bladder cancer cells were examined in this study. An MTT assay showed that 13-acetoxysarcocrassolide was cytotoxic to bladder female transitional cancer (BFTC) cells. We determined that the BFTC cells underwent cell death through apoptosis by flow cytometry. Due to the highly-migratory nature of the BFTC cells, the ability of 13-acetoxysarcocrassolide to stop their migration was assessed by a wound healing assay. To determine which proteins were affected in the BFTC cells upon treatment, a comparative proteomic analysis was performed. By LC-MS/MS analysis, we identified that 19 proteins were up-regulated and eight were down-regulated. Seven of the proteins were confirmed by western blotting analysis. This study reveals clues to the potential mechanism of the cytotoxic effects of 13-acetoxysarcocrassolide on BFTC cells. Moreover, it suggests that PPT1 and hnRNP F could be new biomarkers for bladder cancer. The results of this study are also helpful for the diagnosis, progression monitoring and therapeutic strategies of transitional cell tumors

Korozijski mehanizmi cementiranih zemljin za tri različne raztopine sulfatov

In order to simulate and study the corrosion effects on the compressive strength of cemented soils that could be exposed in a polluted environment, a series of tests were conducted on cemented soil blocks cured with different concentrations of H2SO4, MgSO4, and Na2SO4 solutions. The test results show that the corrosion degree generally increases with the corrosion time and the solution concentration, while the compressive strength decreases with the increasing corrosion degree. The corrosion degree is highest for the Na2SO4 solution, followed by the MgSO4 and H2SO4 solutions. Namely, when the SO4 2- ion exists in a solution, the corrosion degree for the positive ions follows this descending order: Na+, Mg2+, and H+. X-ray diffraction (XRD) phase analyses were performed for the cemented soil samples after corrosion and ionic concentrations. The results show that the compressive strength decreases with an increase of the Mg2+ concentration in the MgSO4 solution and the Na+ concentration in the Na2SO4 solution. At the same time, the strength increases with an increase of the pH value of the H2SO4 solution. Based on the chemical analysis results, the corrosion of H2SO4 or MgSO4 solutions on cemented soils is deemed as a composite action involving the combined resolving and crystallizing corrosion processes. Furthermore, the corrosion of the Na2SO4 solution of cemented soil is a composite action consisting of dissolving and crystallizing.Izveden je bil niz preizkusov na blokih cementiranih zemljin izpostavljenih različnim koncentracijam raztopin H2SO4, MgSO4 in Na2SO4, z namenom simulacije in preučitve učinkov korozije na tlačno trdnost cementiranih zemljin, ki so lahko izpostavljene onesnaženemu okolju. Rezultati preizkusov kažejo, da se stopnja korozije splošno poveča s časom korozije in koncentracije raztopine, medtem, ko tlačna trdnost pada z naraščajočo stopnjo korozijo. Stopnja korozije je največja za raztopino Na2SO4, kateri sledita raztopini MgSO4 in H2SO4. Namreč, če v raztopini obstajajo SO4 2- ioni, stopnja korozije za pozitivne ione sledi v padajočem redu Na+, Mg2+ in H+. Po koroziji in ionski koncentraciji je bila z rentgenskimi žarki izvedena difrakcijska fazna analiza na vzorcih cementiranih zemljin. Rezultati kažejo, da tlačna trdnost pada z večanjem koncentracije Mg2+ v raztopini MgSO4 in koncentracije Na+ v raztopini Na2SO4. Medtem, ko se trdnost veča z večanjem pH vrednosti raztopine H2SO4. Na osnovi rezultatov kemijskih analiz, se korozija raztopin H2SO4 ali MgSO4 na cementiranih zemljinah razume kot sestavljen učinek, ki vključuje kombinirane korozijske procese razpadanja in kristalizacije medtem, ko korozijo raztopine Na2SO4 sestavlja učinek raztapljanja in kristalizacije

The Hankel Determinants from a Singularly Perturbed Jacobi Weight

We study the Hankel determinant generated by a singularly perturbed Jacobi weight w(x,s):=(1−x)α(1+x)βe−s1−x,x∈[−1,1],α>0,β>0s≥0. If s=0, it is reduced to the classical Jacobi weight. For s>0, the factor e−s1−x induces an infinitely strong zero at x=1. For the finite n case, we obtain four auxiliary quantities Rn(s), rn(s), R˜n(s), and r˜n(s) by using the ladder operator approach. We show that the recurrence coefficients are expressed in terms of the four auxiliary quantities with the aid of the compatibility conditions. Furthermore, we derive a shifted Jimbo–Miwa–Okamoto σ-function of a particular Painlevé V for the logarithmic derivative of the Hankel determinant Dn(s). By variable substitution and some complicated calculations, we show that the quantity Rn(s) satisfies the four Painlevé equations. For the large n case, we show that, under a double scaling, where n tends to ∞ and s tends to 0+, such that τ:=n2s is finite, the scaled Hankel determinant can be expressed by a particular PIII′

A Note on the Abelian Complexity of the Rudin-Shapiro Sequence

Let {r(n)}n≥0 be the Rudin-Shapiro sequence, and let ρ(n):=max{∑j=ii+n−1r(j)∣i≥0}+1 be the abelian complexity function of the Rudin-Shapiro sequence. In this note, we show that the function ρ(n) has many similarities with the classical summatory function Sr(n):=∑i=0nr(i). In particular, we prove that for every positive integer n, 3≤ρ(n)n≤3. Moreover, the point set {ρ(n)n:n≥1} is dense in [3,3]

Carbide Nanoparticles Encapsulated in the Caves of Carbon Nanotubes by an In Situ Reduction-Carbonization Route

Carbides (TiC, WC, and NbC) nanoparticles fully encapsulated in the caves of carbon nanotubes (CNTs) were synthesized via an in situ reduction-carbonization route at 600∘C in an autoclave. The structural features and morphologies of as-obtained products were investigated using by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy (HRTEM). HRTEM studies showed that the average diameter of CNTs encapsulated with carbide nanoparticles are in the range of 15–40 nm. The reaction temperature, the reaction time, and the metal catalyst are found to play crucial roles to the product morphology. The growth mechanism of carbide nanoparticles encapsulated in CNTs was discussed in detail

Quercetin attenuates inflammation in LPS‐induced lung epithelial cells via the Nrf2 signaling pathway

Abstract Background Pneumonia is the leading cause of death among children under five, and kill almost two million children each year. Quercetin, a flavonoid polyphenolic compound, exerts many beneficial biological activities, including anti‐inflammatory functions. Our study aimed to investigate the possibility of quercetin as a therapeutic agent for pneumonia and its role in the inflammatory response induced by lipopolysaccharide (LPS). Methods LPS induced human alveolar epithelial cell A549 as a lung inflammation model in vitro. The effects of quercetin on the production of cytokines and the expression of related‐proteins were detected by Enzyme‐Linked ImmunoSorbent Assay and Western Blot, respectively. Cell Counting Kit‐8 assay was used to detect cell viability. flow cytometry was used to measure cell apoptosis. NO levels were also analyzed through NO kit. Results Our results found that quercetin attenuated the release of IL‐1β, IL‐6, PGE2, and nitrite in LPS‐induced A549 cells. In addition, quercetin inhibits cell apoptosis and relieves ROS generation in LPS‐induced A549 cells. Quercetin also inhibits LPS‐induced NF‐κB activation. They have upregulated the expression of nuclear factor erythroid 2 (Nrf2) and HO‐1. Conclusion In conclusion, these results suggested that quercetin attenuates LPS‐induced inflammation in A549 by activating the Nrf2 signaling pathway

Age Hardening Studies of a Cu-4Ti-Cr-Fe Alloy

The microstructure, mechanical properties, and electrical conductivity (EC) of Cu-4Ti-Cr-Fe alloy aged at 773 K in vacuum are studied in this work. The results show that the multiple trace alloying elements have little effect on the microstructure evolution during the aging treatment at 773 K. However, with prolonged aging, the hardness, yield strength, and tensile strength first increase, then decrease. The Cu-4Ti-Cr-Fe alloys show superior hardness and strength performance than other alloys. In both the solid-solution treated and aged cases, the EC decreases if multiple trace alloying elements are added to the Cu-4wt-%Ti alloys, which indicates the CuTi intermetallic compound may have a large negative influence on the EC of copper alloy

Surface Mechanical Attrition Treatment-Induced Dissolution of Cu4Ti Precipitates in Cu—4wt-%Ti Alloy

The microstructural evolution of an overaged Cu-4wt-%Ti alloy associated with surface mechanical attrition treatment (SMAT) has been studied by X-ray diffraction, scanning electron microscope and transmission electron microscopy. The results show that β-Cu4Ti precipitates in the topmost surface layer were dissolved after SMAT, and Cu solid solution phase with a fine grain size of approximately 25 nm was observed. Dislocation activities were the main deformation mechanism of lamellar structure in the overaged Cu-4wt-%Ti alloy. The twinning in lamellar Cu phase was inhibited by the β-Cu4Ti precipitates