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Abstract Predicting the corrosion rate for soil-buried steel is significant for assessing the service-life performance of structures in soil environments. However, due to the large amount of variables involved, existing corrosion prediction models have limited accuracy for complex soil environment. The present study employs three machine learning (ML) algorithms, i.e., random forest, support vector regression, and multilayer perception, to predict the corrosion current density of soil-buried steel. Steel specimens were embedded in soil samples collected from different regions of the Wisconsin state. Variables including exposure time, moisture content, pH, electrical resistivity, chloride, sulfate content, and mean total organic carbon were measured through laboratory tests and were used as input variables for the model. The current density of steel was measured through polarization technique, and was employed as the output of the model. Of the various ML algorithms, the random forest (RF) model demonstrates the highest predictability (with an RMSE value of 0.01095 A/m2 and an R 2 value of 0.987). In light of the feature selection method, the electrical resistivity is identified as the most significant feature. The combination of three features (resistivity, exposure time, and mean total organic carbon) is the optimal scenario for predicting the corrosion current density of soil-buried steel.

Objective In the 9 m level large-diameter shield tunneling, there are no engineering cases using shield method for constructing connecting passages yet. Due to the influence of clearance and evacuation platform height, a certain eccentricity exists between the connecting passage and the main tunnel, resulting in the impact of shield launching and receiving with eccentricity for main tunnel structure. It is necessary to investigate the influence of different opening positions of shield method connecting passage on the internal forces of main tunnel segments. Method Based on a city railway project, numerical simulation method is used to analyze the mechanical response of main tunnel segments during the launching and receiving stages of above connecting passage construction under different eccentricity conditions. Result & Conclusion During the construction of shield method connecting passages, the most critical stage is when the thrust acting on the shield reaction frame is zero. As the eccentricity increases, the convergence deformation of special segments in main tunnel and the internal forces in steel and concrete segments gradually decrease, while the circumferential and longitudinal shear forces gradually increase. The internal forces in ordinary concrete segments adjacent to the special segments on the opening side also increase significantly, which requires special attention in structure design.

Objective To explore the biological function and downstream mechanism of ETS1 in glioma. Methods Bioinformatics and immunohistochemistry were used to analyze the differential expression characteristics of ETS1 in gliomas; qRT-PCR was employed to detect the expression level of ETS1 mRNA and lncRNA X-inactive specific transcript (XIST). CCK-8 and 5-ethyl-2′-deoxyuridine experiments were conducted to detect cell growth. Western blot was used to detect the expression of apoptosis-related proteins (Bax, Bak, Bcl-2). PROMO database was utilized to predict the binding sites between ETS1 and XIST promoter. Dual-luciferase reporter gene assay and chromatin immunoprecipitation-quantitative polymerase chain reaction assays were performed to verify the binding relationship between ETS1 and the XIST promoter region. cBioPortal database was used to analyze the correlation between the expression of ETS1 mRNA and XIST in glioma tissues. Results The expression levels of ETS1 mRNA and protein were significantly upregulated in glioma (P

Background: Ischemic stroke is a common and serious disease with economic and healthcare burdens. Predicting the unfavorable discharge outcome of patients is essential for formulating appropriate treatment strategies and providing personalized care. Therefore, this study aims to establish and validate a prediction model based on machine learning methods to accurately predict the discharge outcome of ischemic stroke patients, providing valuable information for clinical decision making. Methods: The derivation data consisted of 964 patients from Guangdong Provincial People's Hospital and was used for training and internal validation. A favourable discharge outcome was defined as a National Institutes of Health Stroke Scale score of ≤1 or a decrease of ≥8 points compared to the admission score. A predictive model was created based on 88 medical characteristics gathered during the patient's initial admission, using nine machine learning algorithms. The model's predictive performance was compared using various evaluation metrics. The final model's feature importance was ranked and explained using the Shapley additive explanation method. Findings: The random forest model demonstrated the greatest discriminative ability among the nine machine learning models. We created an interpretable random forest model by ranking and reducing the features based on their importance, which included eight features. In internal validations, the final model accurately predicted the discharge outcomes of ischemic stroke with AUC values of 0.903 and has been translated into a convenient tool to facilitate its utility in clinical settings. Conclusions: Our explainable ML model was not only successfully developed to accurately predict discharge outcomes in patients with ischemic stroke and it mitigated the concern of the “black-box” issue with an undirect interpretation of the ML technique.

Wire arc additive manufacturing (WAAM) is a metal 3D printing technique that allows large-scale elements to be built in a relatively timely and cost-effective manner, well suited to the cost-sensitive construction sector. Despite the potential of this novel technology, the basic properties of WAAM materials remain elusive. This paper presents a comparative study on the microstructure and corrosion behaviour of WAAM steel plates and the conventionally rolled Q345 steel. The WAAM steel exhibited comparable corrosion performance to the conventionally-produced steel within twelve days exposure in 3.5 wt% NaCl solution, including the corrosion current density, and the characteristics of steel/concrete interface, determined through electrochemical impedance spectroscopy (EIS) analysis. Post-corrosion observations revealed that preferential dissolution occurred at (Si, Mn)-rich oxide inclusions, in addition to the general corrosion of surrounding steel matrix. The much higher content of Si and Mn element in the feedstock material WAAM steel resulted in slightly higher susceptibility to localised corrosion, compared to the Q345 rolled steel.

Vestibular evoked myogenic potentials (VEMPs), a key electrophysiological technique, is extensively utilized for the clinical evaluation of vestibular function. Patients with Parkinson's disease (PD) often have vestibular dysfunction, with VEMPs abnormalities being the most common. Based on the brief introduction of VEMPs technique, this review summarizes the features of VEMPs abnormalities, its association with clinical phenotype and underlying pathophysiological basis in patients with PD, so as to provide guidance for clinical research and practical application.

In recent years, several research units have introduced solid-state nuclear magnetic resonance (NMR) spectrometers. So far, solid-state NMR spectrometers have not been domestically manufactured and the equipment is completely dependent on imports. Therefore, both the instruments and sample preparation systems are expensive. The sample loading rotor is the crucial consumable in the magic angle spinning (MAS) NMR experiment. However, the extremely tough requirement on dimensional precision poses a great challenge in the machining of rotors. By analyzing the characteristics and practical applications of the imported 3.2 mm rotor and its sample preparation tools, we optimized the connection between the rotor parts, improved the sealing of rotor, and developed the MAS rotor and its sample preparation tools independently. The test results show that the self-made MAS rotor can run normally at 12 kHz, which meets the requirements of conventional solid-state NMR experiments. The sample preparation toolbox has advantages of simplicity and safety.

Increasing array gains is one of the keys to improving underwater targets’ detection capabilities. This paper presents a high-gain approach for a vector hydrophone vertical array (VHVA) that combines white noise gain constraint (WNGC) with vector joint processing to preserve strong robustness and provide noticeable gains. Firstly, this approach treats the VHVA as four independent sub-arrays and achieves sub-array supergains by decorrelating noise using WNGC. The beam outputs of the four sub-arrays are then equated to a single-vector hydrophone, the combination gain of which is obtained by leveraging the strong signal correlation and the weak noise correlation between the sound pressure and the particle velocity. Lastly, the sub-array supergain and combination gain are superposed to provide the spatial gain of the VHVA. It is also summarized that low-frequency signals, coherent noise, accurate elevation-angle estimation, and stable phase differences are required for the VHVA to achieve supergain. The simulation and sea trial confirm that this approach can effectively boost the array gain. The maximum spatial gain in the experiment was increased by 9 dB at a range twice the sea’s depth while operating at a low frequency. This method shows enormous potential for improving the performance of deep-sea target detection.

Objective: This study aimed to investigate the antioxidation and synergistic effect of flavonoid extract of Zanthoxylum armatum DC. Methods: DPPH radical and ABTS radical scavenging methods were used to evaluate the antioxidant activity of flavonoids extract from Z. armatum, and the synergies of flavonoids extract with vitamin C and rutin complex were studied by adding method. Results: The semi-inhibitory concentrations of DPPH free radical and ABTS free radical IC50 were 0.03 and 0.062 mg/mL, respectively, showing strong antioxidant activity. The antioxidant activity of the complex composed of flavonoid extract and vitamin C or rutin was high, and the antioxidant activity of the complex composed of vitamin C and flavonoid extract was higher than that of rutin and flavonoid extract when the ratio was 1∶1. Conclusion: The flavonoids of Z. armatum have strong antioxidant activity, and their complex composed of vitamin C and rutin can improve the scavenging capacity of DPPH free radical and ABTS free radicals. The extracted flavonoids have antioxidant synergistic effect, and can be used as a potential source of natural antioxidants.

The oxidation of natural rubber (NR) leads to a decrease in mechanical properties, even resulting in failure of NR products. Many studies focusing on this single factor have failed to fully elucidate the impact of tropical island environment on NR properties. Based on this concern, the synergistic effect of thermal oxygen and ultraviolet (UV) aging on NR was systematically studied. The results revealed that thermal oxygenation can promote UV aging, which leads to the appearance of surface cracks and deepening of color. With the extension of aging time, the mechanical properties of NR correspondingly decreased. Besides, to deeply understand the mechanism of the synergistic effect of thermal oxygen and UV aging on NR, we selected squalene to simulate and analyze the molecular structure changes in NR. Based on these results, a possible synergistic effect of thermal oxygen and UV aging mechanisms on NR could be proposed.

With the rapid development of the copper-based composite in the field of electrical contact material industry, the problem of poor arc erosion resistance of the copper-based material becomes more and more prominent. Improving the arc erosion resistance of the copper-based composite is an urgent problem to be solved. Cu-Al2O3/30Mo/3SiC and 0.5Y2O3/Cu-Al2O3/30Mo/3SiC electrical contact composites were prepared in a fast-hot-pressing sintering furnace. The microstructure and phase structure of the composites were analyzed by using a scanning electron microscope, transmission electron microscope, and X-ray diffraction meter, respectively. The arc erosion properties of the composites at 25 V, DC and 10-30 A were investigated by using a JF04C electric contact tester. The mass loss of the composites was reduced by 77.8%, and the arc erosion rate was reduced by 79.6% after the addition of nano-yttrium oxide under the experimental conditions of 25 V, DC and 30 A. At the same time, the arc energy and welding force of the composite after switching operations decreased, indicating that the addition of nano-yttria improved the arc erosion resistance of the composite. This work provides a new method for improving the arc erosion resistance of the copper-based composite contact material.

Central heating system faults affect building energy consumption and indoor thermal comfort significantly. To aim at the balance between thermal comfortable and energy-saving of the heating system for high-rise residential buildings, this paper proposes a method for the central heating system of high-rise residential buildings based on distributed model predictive control. The method analyzes the coupling factors between adjacent rooms’ temperature. Based on the state space method, a multivariable indoor temperature model is established and verified. The distributed model predictive control method is used to control and optimize the indoor temperature, and the load distribution of the circulating water pump in the heat exchange station is optimized according to the predicted heat demand. The results demonstrate that the indoor temperature after distributed model predictive control can stable near the set value. Compared with the centralized control methods, the proposed methodology can reduce energy consumption by 14.28%. Meanwhile, the efficiency of water pumps is increased by 16.74% after using the distributed control strategy.

Cryptococcus gattii is a kind of basidiomycetous yeast, which grows in human and animal hosts. C. gattii has four distinct genomes, VGI/AFLP4, VGII/AFLP6, VGIII/AFLP5, and VGIV/AFLP7. The virulence of C. gattii is closely associated with genotype and related stress-signaling pathways, but the pathogenic mechanism of C. gattii has not been fully identified. With the development of genomics and transcriptomics, the relationship among genes, regulatory mechanisms, virulence, and treatment is gradually being recognized. In this review, to better understand how C. gattii causes disease and to characterize hypervirulent C. gattii strains, we summarize the current understanding of C. gattii genotypes, phenotypes, virulence, and the regulatory mechanisms.

This paper proposes an underwater broadband target depth estimation method based on the multipath arrival structure in medium and short-range deep-sea environments. The proposed approach involves separating the multipath rays arriving at the vertical line array using the matched filtering technique. The combined beamforming is then applied to the vector hydrophone vertical array (VHVA) to obtain more accurate elevation angle estimates. The components of the interference sound field at different distances are judged, and the signal received by the array is compensated using suitable estimated angles. Finally, the multipath time delay difference is extracted from the pulse peaks of the compensated signal, and the target depth is estimated by establishing the relationship among the multipath time delay difference, the elevation angle and depth. Simulations and experiments demonstrate the effectiveness of this method in reducing the depth estimation bias and avoiding the misjudgment of surface or submerged targets.

Merging the education model of clinical-type medical graduates into a double-track system, medical colleges and teaching hospitals are facing challenges of more requirements on cultivating graduates. In order to help the graduates to join in standardized resident training in an active attitude in order to strengthen their capacity building for learning and scientific research, this article discussed the development of integrated capacity during the training of clinical-type medical graduates from three aspects as clinical capacity, innovation spirit and personal quality.

Nano-Al2O3 dispersion-strengthened Cu20W composite was fabricated by vacuum hot-pressing sintering process. The electrical conductivity, relative density, and Brinell hardness were tested, respectively. The gleeble-1500D thermomechanical simulator was used to conduct isothermal compression with strain rates ranging from 0.001 to 10 s−1 and the temperatures ranging from 650 to 950°C. The microstructure of the Cu–Al2O3/20W composite was observed using an optical microscope and a transmission electron microscope, and the true stress–strain curves were analyzed. In addition, the influence of the nano-Al2O3 and tungsten on the thermal deformation process of the composite was analyzed. The relationship and interaction among work hardening, dynamic recovery, and dynamic recrystallization were illustrated. The results show that nano-Al2O3 particles pin dislocations and inhibit dynamic recovery and dynamic recrystallization. Consequently, the Cu–Al2O3/20W composite has typical dynamic recovery characteristics. Hence, the Cu–Al2O3/20W composite possesses outstanding high-temperature performance. The optimal processing domain of the Cu–Al2O3/20W composite ranged from 760 to 950°C with strain rates ranging from 0.01 to 0.1 s−1. Furthermore, the constitutive equation of the Cu–Al2O3/20W composite is established, and the activation energy is 155.069 kJ mol−1.

A review of the relevant research reveals that the concept of “professional growth” is understood to refer to an all-encompassing developmental process that occurs throughout a person’s career as well as their entire life, and it is acknowledged as a phrase that is connected to other ideas. In addition, we can say that human attributes and circumstances are not the only factors that play a role in the process of professional development, but social and institutional experience also play a role in it. After that, this research is shown, which has personal dimensions for beliefs (B), co-workers (CW), culture inheritance (CI), customs (C), information and communications technology (ICT), and learning practice (LP). The research is formed to illustrate that promotion of professional growth in workplaces is connected to the mentioned variables. This study was based on the working experience of different backgrounds people. We tried to check how their attributes could influence their working practices and learning practices. A semi-structured questionnaire was adopted from existing literature and modified as per the study area. B > LP (β = 0.022; p 0.010), CI- > LP (β = 0.368; p 0.000), C- > LP (β = 0.210; p 0.000), and ICT- > LP (β = 0.410; p 0.000) were found to be significant using PLS-SEM direct path analysis.These results offer support to hypotheses H1, H3-H6 accepted and H2 rejected. As control variables, we looked at the respondents’ age, education, and gender. Gender (β = 0.006; p 0.846) showed insignificant relationships with LP, whereas age (β = −0.103; p 0.001) and education (β = −0.072; p 0.034) showed significant relationships with the dependent variable. gender does not have any relationship with learning practices (LP), but age and education can be favorable control variables, and an aged and experienced person can have more impacts on LP and impacts on independent variables.

Abstract Fiber-optic hydrophone (FOH) is a significant type of acoustic sensor, which can be used in both military and civilian fields such as underwater target detection, oil and natural gas prospecting, and earthquake inspection. The recent progress of FOH is introduced from five aspects, including large-scale FOH array, very-low-frequency detection, fiber-optic vector hydrophone (FOVH), towed linear array, and deep-sea and long-haul transmission. The above five aspects indicate the future development trends in the FOH research field, and they also provide a guideline for the practical applications of FOH as well as its array.

Ocean fronts are mostly determined according to the horizontal temperature gradient, and various selection criteria may lead to different frontal zones. This study proposes a frontal zone delineation method based on sound speed profile. In this paper, the sound speed profile of the Kuroshio intrusion front in the Luzon Strait is classified via fuzzy cluster analysis based on transitive closure and fuzzy C-means algorithm. At the same time, considering that ocean fronts affect sound propagation, we verify the effectiveness of the two algorithms in terms of sound transmission loss. The results show that in different depth ranges, the effectiveness of the two algorithms differs in identifying the frontal zone. At depth below 300 m, the sound speed profile changes drastically, and fuzzy cluster analysis based on the transitive closure is more effective. At 300–700 m depth where the sound speed profile tends to be stable, the fuzzy C-means algorithm is more effective. At 700–1000 m depth near the SOFAR axis (the depth of the minimum sound speed), fuzzy cluster analysis based on the transitive closure is more effective. Finally, based on the sound speed profile, we combine both algorithms for the first time to obtain a three-layer geometric optimized structure of the Kuroshio intrusion front in the Luzon Strait. The classification of sound speed profiles via the two fuzzy cluster algorithms provides a new way to judge the frontal zone in different depth ranges and reconstruct geometric models of ocean fronts.

C5H5N5O3, orthorhombic, Pnma (no. 62), a = 13.4643(13) Å, b = 6.2866(10) Å, c = 9.1138(9) Å, V = 771.43(16) Å3, Z = 4, Rgt(F) = 0.0517, wRref(F2) = 0.1317, T = 293 K.

Abstract Introduction Neck pain is a common condition that leads to serious pain, disability, and increased healthcare costs worldwide. Pharmacotherapy is one of the most common strategies to reduce neck pain in patients. The aim of this study was to analyze the real-world pattern of drugs prescribed for patients with neck pain in the USA. Methods Data on individuals who reported current neck pain in the 2009−2010 US National Health and Nutrition Examination Survey (NHANES) and with a history of persistent pain for at least 6 weeks or 3 months were extracted from the NHANES database. Those included in the study were divided into three groups based on the duration of pain: the without neck pain group (Group A); subacute group (Group B) with a history of 6 weeks of neck pain; and the chronic neck pain group (Group C) with a history of 3 months of neck pain. The use and duration of medication prescribed for Group A, B, and C patients were compared. Results The analysis revealed that opioid use was significantly more prevalent in the subacute and chronic neck pain group than in the without neck pain group (Group A) (adjusted odds ratio [aOR] 4.20, 95% confidence interval [CI] 2.07–8.52 and aOR 7.00, 95% CI 4.32–11.33, respectively). The factors strongly associated with higher opioid use included older age, low education level, and low family income. In the chronic neck group, opioids, followed in decreasing order of frequency by acetaminophen and nonsteroidal anti-infammatory drugs, were the most common analgesics used in combination with other analgesics. Conclusion Our analysis of the data shows that the long-term excessive use of opioids and the underutilization of other analgesics are two major issues in the treatment of neck pain in the USA. Possible improvements include improved education of patients by healthcare professionals on the use of opioids and more consideration given to non-pharmacotherapy options. Our results reveal the potential problem in pharmacotherapy choices for neck pain treatment and may help improve the current clinical practice in the USA and other countries.

When the art images are restored by the virtual restoration method, there are problems such as insufficient clarity and more noise in the reference image. An improved cartoon-texture decomposition method for art image fusion is proposed. The nonlinear local total variation component is used as the indicator function of image decomposition to obtain the image cartoon structure component and texture oscillation component. According to the oscillation component’s strong repetitiveness and structural directionality, the image texture part is filtered by combining the improved directional diffusion algorithm. Using the sparse coefficients of the fused cartoon component and the sparse coefficients of the texture component, the cartoon and texture of the image is inverse transformed and weighted and summed to obtain the recovered image after fusion. The experimental results show that this paper has a good effect after image fusion, and the recovered clarity is higher, which can better express the basic information of the source image; compared with several decomposition fusion methods commonly used at present, this paper has better recovery performance and detail processing ability and preserves the edge information of essential details in the image while filtering and denoising and is more excellent in objective performance evaluation indexes such as PSNR and SSIM. It can be used as a reference basis in the restoration process of art images.

As one of the widespread physical phenomena in the global ocean system, the ocean front has a very important influence on underwater sound propagation. Firstly, this paper systematically reviews several methods for the detection of ocean fronts in the past decades, including traditional oceanographic methods, artificial intelligence methods, and acoustic methods, highlighting the advantages and disadvantages of each method. Next, some modeling studies of ocean fronts are reported in this paper. Based on the above research, we pay more attention to research progress on the acoustic effects of ocean fronts, including simulation analysis and experimental research, which has also been the focus of underwater acousticians for a long time. In addition, this paper looks forward to the future development direction of this field, which can provide good guidance for the study of ocean fronts and their acoustic effects in the future.

The two-stage suspension system (TSSS) is designed for the fiber optic vector hydrophone (FOVH) to isolate the vibration from the mooring rope. The acceleration transmissibility of the TSSS is studied theoretically and experimentally. The results show that the TSSS has a major advantage over the traditional one-stage suspension system (OSSS). Typically, the vibration isolation of the TSSS is demonstrated to be over 25 dB higher than that of the OSSS at 100 Hz. Meanwhile, it is demonstrated that the TSSS has little negative influence on the in-band acceleration response of the FOVH. The TSSS has the prospect of reducing the mechanical noise of the FOVH, which is conducive to suppressing the self-noise and enhancing the ability of weak signal detection.

A theoretical and experimental study on the stimulated Brillouin scattering (SBS) threshold for optical pulse in the presence of modulation instability (MI) in long optical fiber is presented. The effects of MI on the SBS gain and threshold are analyzed based on the coupled-wave equation. An analytic expression is obtained to calculate the SBS threshold in the presence of MI. Numerical simulation is conducted to study the effects of the repetition rate and amplified spontaneous emission (ASE) noise on the SBS threshold for optical pulses. An experiment is conducted, and the results agree well with the theoretical analysis. The results clearly reveal how MI affects the Brillouin gain and SBS threshold of optical pulses in long optical fiber. The SBS threshold is affected by the ASE noise level and the repetition rate of the optical pulse. The study is helpful for the power evaluation of interferometric fiber sensing systems and optical power transmission systems.

Modulation instability (MI) is the main limitation factor of the maximum optical power in long-haul phase-sensitive optical time domain reflectometry (Φ-OTDR), and induces signal fading and serious phase noise. In this paper, a method of coherent seed injection is proposed to suppress the MI-induced phase noise in long-haul Φ-OTDR. The spontaneous MI is suppressed by stimulating induced MI in an optical fiber. The visibility of the signal in Φ-OTDR is enhanced and the phase noise is suppressed significantly. This paper offers an effective method to increase the maximum input power with the MI-induced phase noise suppressed in the long-haul Φ-OTDR system. As a result, the maximum input power and sensing distance can be potentially increased, which is greatly beneficial to the enhancement of the performance of long-haul Φ-OTDR.

A distributed fiber optic hydrophone (DFOH) is a new type of fiber optic hydrophone (FOH) with adjustable structure. The dependence of the directivity of a DFOH on array structure is theoretically and experimentally studied. The directivity function of a sensing channel and that of a DFOH are derived. Based on the directivity function, the simulations are performed. Finally, the theoretical analysis is demonstrated by the experiments performed on Qingyang lake, and the results reveal that the longer sensing channel length guarantees the lower first-order side lobe and the narrower main lobe. As the channel length increased from 1 to 3, the main lobe width and first-order side lobe height decreased by 4.9° and 6 dB, respectively. In addition, channel spacing is irrelevant to directivity as the spacing is shorter than the wavelength. As the channel spacing increased from 0 to 1, the variations of the main lobe width and first-order side lobe height are lower than 0.5° and 0.94 dB, respectively. This study would provide guidance for the structure design of a distributed fiber optic hydrophone in signal processing.

Mediterranean eddies (meddies) play an essential role in transferring heat, salinity and momentum into the Atlantic Ocean. The rate of heat (and salt) flux from the meddy and its ultimate lifetime are key proxies to understanding how meddies impact the redistribution of heat and salt in the ocean system. A Mediterranean eddy was observed in the Gulf of Caidz in 2007 using seismic and hydrographic data. The spatial distribution of turbulent dissipation rates around the meddy is estimated from the seismically derived internal wave spectra subrange using fine-scale parameterization. Turbulent dissipated rates are lowest (10−11 W/kg) within the core of the meddy but rise by nearly two orders of magnitude at the upper and lower boundaries, where signs of double diffusive convection are observed. Along the left flank of the meddy, thermohaline intrusions and interleaving of water masses are found in inverted temperature and salinity profiles, transporting heat laterally from the warm core to the Atlantic water with a flux of around 470 Wm−2. The meddy presented in this study is shown to decay in 2 years, primarily due to the heat loss associated with thermohaline intrusions. For the first time, heat fluxes around the meddy and its lifetime are quantified using seismic oceanography data, and the methods proposed here can be applied to more seismic datasets in the global oceans.

The fretting wear behavior of micro-arc oxidation (MAO) treated ZK60 magnesium alloy under simulated bone plate-screw service condition was investigated. The MAO treatments on the surface of ZK60 magnesium alloy were conducted with different duty cycles of 20%, 30%, and 40%, respectively. Results show that the surface hardness and corrosion resistance of MAO-treated magnesium alloy specimens with different duty cycles are similar and are improved significantly in comparison with the bare magnesium alloy. Under the simulated bone plate-screw fretting condition, the worn surface of the bare magnesium alloy is characterized by ploughs and corrosion pits, accompanied with a high wear volume of 13.1×106μm3, while the wear is obviously decreased and mainly dominated by ploughs on the surface of the MAO-treated magnesium alloy. With the increase of duty cycle, the wear volume is 6.6×106,6.1×106μm3 and 6.5×106μm3, respectively. There is no obvious difference in the fretting wear behavior and the worn surface morphology among the MAO-treated ZK60 magnesium alloy specimens with different duty cycles. In sum, the anti-fretting wear performance of ZK60 magnesium alloy can be improved obviously after micro-arc oxidation treatment, and the duty cycle has little influence on the microstructure and fretting wear properties of the MAO layer on ZK60 magnesium alloy under the given experimental conditions.

Flow-injection mass spectrometry (FIMS) coupled with a chemometric method is proposed in this study to profile and distinguish between rhizomes of Smilax glabra (S. glabra) and Smilax china (S. china). The proposed method employed an electrospray-time-of-flight MS. The MS fingerprints were analyzed using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) with the aid of SIMCA software. Findings showed that the two kinds of samples perfectly fell into their own classes. Further predictive study showed desirable predictability and the tested samples were successfully and reliably identified. The study demonstrated that the proposed method could serve as a powerful tool for distinguishing between S. glabra and S. china.

This paper proposes an H_/H∞ fault detection observer method by using generalized output for a class of polytopic linear parameter-varying (LPV) systems. As the main contribution, with the aid of the relative degree of output, a new output vector is generated by gathering the original output and its time derivative, and it is feasible to consider H_ actuator fault sensitivity in the entire frequency for the new system. In order to improve actuator and sensor fault sensitivity as well as guarantee robustness against disturbances, simultaneously, an H_/H∞ fault detection observer is designed for the new LPV polytopic system. Besides, the design conditions of the proposed observer are transformed into an optimization problem by solving a set of linear matrix inequalities (LMIs). Numerical simulations are provided to illustrate the effectiveness of the proposed method.

As one of the most common mesoscale phenomena in the ocean, the ocean front is defined as a narrow transition zone between two water masses with obviously different properties. In this study, we proposed an ocean front reconstruction method based on the K-means algorithm iterative hierarchical clustering sound speed profile (SSP). This method constructed the frontal zone from the perspective of SSP. Meanwhile, considering that acoustic ray tracing is a very sensitive tool for detecting the location of ocean fronts because of the strong dependence of the transmission loss (TL) on SSP structure, this paper verified the feasibility of the method from the perspective of the TL calculation. Compared with other existing methods, this method has the key step of iterative hierarchical clustering according to the accuracy of clustering results. The results of iterative hierarchical clustering of the SSP can reconstruct the ocean front. Using this method, we reconstructed the ocean front in the Gulf Stream-related sea area and obtained the three-dimensional structure of the Gulf Stream front (GSF). The three-dimensional structure was divided into seven layers in the depth range of 0–1000 m. Iterative hierarchical clustering SSP by K-means algorithm provides a new method for judging the frontal zone and reconstructing the geometric model of the ocean front in different depth ranges.

As a mesoscale phenomenon of the ocean, the ocean front can directly affect the structural characteristics of sound speed profiles and further affect the acoustic propagation characteristics of the sea area. In this paper, we use the fuzzy C-means (FCM) algorithm to cluster the surface sound speed in the sea area of the Kuroshio Extension (KE) and detect the frontal zone of Kuroshio Extension (KEF). At the same time, the sound speed profile (SSP) is used instead of the temperature profile to establish the model of the sound speed field in the front area of the Kuroshio Extension and to improve the theoretical model of the ocean front. Compared with the actual ocean front calculated by reanalysis data, the root means square error (RSME) of the transmission loss (TL) calculated by the model is controlled below 6 dB, which proves the validity of the model. Finally, we propose the melt function in the model to forecast the depth change of the acoustic convergence area. Compared with the actual calculation result based on reanalysis data, the root means square error (RSME) of the depth forecasting after the frontal zone is 43.3 m. This reconstruction method does not rely on the high spatial resolution data of the whole sea depth and can be of referential significance to acoustic detection in the ocean front environment.