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对涡轴发动机压气机叶片附着物进行分析, 根据附着物特征研究了针对性的清洗介质并进行了实验验证, 为压气机性能恢复奠定了基础。采用扫描电子显微镜、热重分析、红外光谱等方法对压气机叶片附着物进行分析, 结果表明压气机导流叶片和静子叶片附着物的颗粒状态、元素含量、有机物类型等特征存在明显区别。利用分析得到的附着物特征提出了新型的水基微乳型清洗介质, 实验表明新型清洗剂对压气机附着物的清洗效果良好。对清洗剂的金属材料腐蚀性能进行验证, 实验表明新型清洗剂具有良好的缓蚀性能。

A mussel-inspired multiwalled carbon nanotube (MWCNT) nanocomposite (MWCNTs@CCh-PEI) was prepared by the co-deposition of catechol (CCh)/polyethyleneimine (PEI) and modification of MWCNTs for the efficient removal of methyl orange (MO). The effects of MO solution pH, contact time, initial MO concentration, and temperature on the adsorption capacity of MWCNTs@CCh-PEI were investigated. The results indicate that the adsorption capacity of MWCNTs@CCh-PEI was two times higher than that of pristine MWCNTs under the same conditions. The adsorption kinetics followed the pseudo-second-order model, suggesting that the adsorption process was chemisorption. The adsorption isotherm shows that the experimental data were fitted well with the Langmuir isotherm model, with a correlation coefficient of 0.9873, indicating that the adsorption process was monolayer adsorption. The theoretical maximum adsorption capacity was determined to be 400.00 mg·g−1. The adsorption thermodynamic data show that the adsorption process was exothermic and spontaneous. More importantly, the adsorption capacity of MWCNTs@CCh-PEI showed no significant decrease after eight reuse cycles. These results demonstrate that MWCNTs@CCh-PEI is expected to be an economical and efficient adsorbent for MO removal. [ABSTRACT FROM AUTHOR]

Among renewable energy sources, wind energy is regarded as one of the fastest-growing segments, which plays a key role in enhancing environmental quality. Wind turbines are generally located in remote and harsh environments. Bearings are a crucial component in wind turbines, and their failure is one of the most frequent reasons for system breakdown. Wind turbine bearing faults are usually very localized during their early stages which is precisely when they need to be detected. Hence, the early diagnosis of bearing faults holds paramount practical significance. In order to solve the problem of weak pulses being masked by noise in early failure signals of rolling element bearings, a novel fault diagnosis method is proposed based on the combination of complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and an improved TFR demodulation method. Initially, the decomposition of vibration signals using CEEMDAN is carried out to obtain several intrinsic mode functions (IMFs). Subsequently, a novel KC indicator that combines kurtosis and the correlation function is designed to select the effective components for signal reconstruction. Finally, an innovative approach based on the continuous wavelet transform (CWT) for multi-scale demodulation analysis in the domain of time–frequency representation (TFR) is also introduced to extract the envelope spectrum. Further fault diagnosis can be achieved by the identification of the fault characteristic frequency (FCF). This study focuses on the theoretical exploration of bearing faults diagnosis algorithms, employing modeling and simulation techniques. The effectiveness and feasibility of the proposed method are validated through the analysis of simulated signals and experimental signals provided by the Center for Intelligent Maintenance Systems (IMS) of the University of Cincinnati and the Case Western Reserve University (CWRU) Bearing Data Center. The method demonstrates the capability to identify various types of bearing faults, including outer race and inner race faults, with a high degree of computational efficiency. Comparative analysis indicates a significant enhancement in fault diagnostic performance when compared to existing methods. This research contributes to the advancement of effective bearing fault diagnosis methodologies for wind turbines, thereby ensuring their reliable operation. [ABSTRACT FROM AUTHOR]

Diverse diseases and increasing prevalence pose a serious threat to public health. Point‐of‐care testing (POCT) techniques have imposed superior requirements over sensitivity, selectivity, robustness, affordability, and high‐throughput. However, transient signal, complex sample pretreatment, and low signal‐to‐noise ratio make POCT severely limited in detection accuracy, efficiency, and sensitivity. Here, an enzyme‐assisted magnetic large‐mesoporous nanoreactor (FS) is constructed for achieving persistent‐chemiluminescence signal output and eliminating matrix interference in disease diagnosis. The core‐shell structured FS synthesized via an interface coassembly method exhibits uniform size, large and open mesopores (≈22 nm), and intrinsic magnetic separability. Such unique FS acts as efficient nanoreactor for confined cascade reactions enable efficient persistent‐chemiluminescence (pCL) signal transduction and high‐SNR chromogenic analysis of diverse biomarkers. The developed pCL assays facilitate high‐sensitive determination of chronic disease biomarkers glucose and uric acid with detection limits (DL) of 5.4 mg L−1 and 151.2 ng L−1, respectively. The proposed chromogenic immunoassay enables an ultrasensitive and visual determination of alpha‐fetoprotein with a DL of 1.2 ng L−1, which is superior to previously published immunoassays. The feasibility of the developed methods for real‐world applications are demonstrated in 159 clinical serum samples, and the determination results agree well with the clinical data. The proposed technique is expected to promote highly sensitive disease diagnosis in primary medical institutions and resource‐limited areas since not relying on expensive automatic sampling and testing instruments. The good flexibility of the customizable nanoreactor makes it a powerful tool for developing various POCT techniques for rapid, sensitive, and accurate diseases diagnosis. [ABSTRACT FROM AUTHOR]

The characteristics of the thermal evolution of aromatic maturity parameters, such as methyl phenanthrene, alkylated dibenzothiophene, dehydroxy-tocopherol and triaromatic-sterane series compounds are discussed on the basis of molecular organic geochemistry and GC-MS analysis of the source rocks in the Dongling area of the Songliao Basin. The distribution characteristics of aromatic hydrocarbon chromatography, the methyl phenanthrene index (MPI), the ratio of β/γ dehydroxy-tocopherol, 4-/1-MDBT, 4,6-/1,4-DMDBT, TASC27 (20R)/C28 (20R), the content of the triaromatic-sterane series and vitrinite reflectance measurements all suggest that the Lower Cretaceous Quantou Formation source rock is in the middle stage of maturity, whereas the Lower Cretaceous Yingcheng Formation and the Upper Jurassic Huoshiling Formation source rocks have reached a high maturity stage.

Ag nanowires coated with TiO2 nanosheets (AgNWS@TiO2NS, AWT) have been successfully synthesized via a one-pot hydrothermal synthesis. Importantly, the prepared AWT shows enhanced photocatalytic activity compared with Degussa P25, which is attributed to its continuous hierarchical structures, special conductive channel and localized surface plasmon resonance (SPR). Additionally, these prepared AWT were exploited as an electron conductor and scattering material in the TiO2 composite photoanodes of dye-sensitized solar cells (DSSCs). The highest energy conversion efficiency of 6.98% was achieved when the AWT doping rate in the photoanode slurry was 5 wt%. Both enhanced Isc and Voc are attributed to the increased photo-absorption efficiency from the localized SPR. The potential enhanced light-scattering effect and faster photoelectric transmission efficiency of the AWT in the photoanode. [ABSTRACT FROM AUTHOR]