Energy Spectrum Analysis Research Articles

A wind tunnel study of adverse pressure gradient impact on wind turbine wake dynamics

Wind tunnel experiments were conducted to investigate the impact of an adverse streamwise pressure gradient on the wake dynamics of a small-scale horizontal-axis wind turbine. The study used high-frequency constant temperature hotwire anemometry to measure wake velocities up to 7 rotor diameters (dT) downstream. Two cases were studied: zero pressure gradient (ZPG) and adverse pressure gradient (APG). Experimental conditions included a Reynolds number based on the rotor diameter of Re≈6.7×104 and an inflow velocity of 7 m/s. The results show significant differences between the ZPG and APG cases as the wake progresses downstream. The APG case exhibits a higher maximum velocity deficit in the far wake and a more distorted, oval-shaped wake than the ZPG case. Turbulence intensity trends also differ, with a decreasing trend in the ZPG case and an increasing trend in the APG case. Energy spectra analysis at specific wake locations offers insights into flow structure development. In both cases, small-scale (high-frequency) energy decreases as the wake advances, while large-scale (low-frequency) energy increases. Specifically, the adverse pressure gradient attenuates certain large-scale flow structures λx/dT∈[0.05,0.2], corresponding to f∈[20,100]Hz near the rotor tip height and narrows downstream. Additionally, in the APG case, energy increases in the lower half of the wake for flow structures ranging from λx/dT∈[0.04,0.5], or f∈[10,100]Hz near the rotor, narrowing further downstream. The results suggest that an adverse pressure gradient enhances turbulence and hinders velocity recovery toward freestream conditions in the wake of a wind turbine.

Analysis of internal material characteristics of cathode crater of micro-cathodic arc thruster

In this study, the material loss relationship between the electrodes of a micro-cathodic arc thruster was investigated by adjusting the input voltage. The crater morphology of the micro-cathodic arc thruster was observed with a scanning electron microscope. The internal crater material was analyzed with an energy spectrum analyzer. On this basis, the arc path is obtained and the material loss of the structure between the electrodes of the micro-cathodic arc thruster was studied through further numerical simulation. The experimental and simulation results show that with a change in the Power processing unit (PPU) input voltage of the micro-cathodic arc thruster, the material distribution in the cathode crater and the discharge channel between the electrodes changed, affecting the bombardment of ions between the electrodes of the thruster on the insulating structure and conductive coating. In engineering applications, regulation of the arc breakdown path can effectively reduce the total energy of ion bombardment on the wall.

Failure Analysis of an Elbow Tube Break in a Pyrolysis Furnace

The pyrolysis furnace, a critical component in a pyrolysis unit, inevitably faces operational challenges during its use. This study investigates a case of pyrolysis furnace failure, particularly focusing on an occurrence at the 90° lug elbow and furnace tube weld. The failure, characterized by a comprehensive fracture of the furnace tube in the circumferential direction along the weld vicinity, transpired within a timeframe significantly shorter than one-third of the design life. To unravel the root cause, a series of experiments was conducted on a sample extracted from the failed tube. These experiments, comprising visual inspection, chemical composition analysis, metallographic examination, microstructure analysis, fracture scanning electron microscopy, and energy spectrum analysis, collectively aimed at a comprehensive understanding of the failure mechanisms. The results disclosed that the fracture between the lug elbow and the inlet pipe stemmed from the presence of porosity and inclusions in the butt weld. The initiation of cracks was traced to the pores and inclusions in the fusion line of the inner wall of the pyrolysis tube, extending to connect with the pores in the heat-affected zone on the side of the pyrolysis tube parent material. Subsequently, under the influence of high temperature and stress, the cracks propagated, crept, and expanded along the circumference of the pyrolysis tube parent material until the final fracture occurred. In light of these findings, practical recommendations are proposed to mitigate the risk of similar failures in the future.

Preparation of cerium-containing nanoporous titanium coatings for osseointegration and their promotion of osteogenic differentiation and anti-inflammatory properties

Conventional implants face many problems, such as failure to form good osseointegration and peri-implantitis in the early stage of implantation. It has been shown that hydroxyapatite (HA) has good osteoconductive ability. Also considering the potential of cerium oxide in osteogenesis and anti-inflammation, we prepared cerium-containing nanoporous HA coatings on the surface of pure titanium using the micro-arc oxidation (MAO) technique. The surface morphology of the coating was observed by scanning electron microscopy (SEM). The mechanical strength of the coating was examined by the ultrasonic oscillator. The elemental composition of the coating was examined by energy spectrum analysis (EDS). The ion release capacity of the cerium-containing coatings was examined by inductively coupled plasma emission spectrometry (ICP-OES). The hydrophilic properties of the coatings were examined by the hydrophilic angle test. In vitro, experiments were performed using rat bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophages (Raw264.7). The biosafety of the cerium-containing coating was verified by live-dead staining and CCK-8 proliferation assay. The osteogenic and anti-inflammatory ability of the cerium-containing coating was examined by immunofluorescence staining and quantitative polymerase chain reaction (q-PCR). In addition, ion experiments were used to further demonstrate the osteogenic and anti-inflammatory potential of cerium ions. Subsequent animal experiments further demonstrated the osteoinductive potential of the cerium-containing HA coating. In conclusion, our cerium (HA)-containing coatings prepared by micro-arc oxidation on titanium surfaces show excellent osteogenic and anti-inflammatory properties, which are expected to improve the functionality of clinical implants and also lay the foundation for the clinical application of cerium ions.

Genome-wide identification of the cation/proton antiporter (CPA) gene family and functional characterization of the key member BnaA05.NHX2 in allotetraploid rapeseed

Rapeseed (Brassica napus L.) is susceptible to nutrient stresses during growth and development; however, the CPA (cation proton antiporter) family genes have not been identified in B. napus and their biological functions remain unclear. This study was aimed to identify the molecular characteristics of rapeseed CPAs and their transcriptional responses to multiple nutrient stresses. Through bioinformatics analysis, 117 BnaCPAs, consisting of three subfamilies: Na+/H+ antiporter (NHX), K+ efflux antiporter (KEA), and cation/H+ antiporter (CHX), were identified in the rapeseed genome. Transcriptomic profiling showed that BnaCPAs, particularly BnaNHXs, were transcriptionally responsive to diverse nutrient stresses, including Cd toxicity, K starvation, salt stress, NH4+ toxicity, and low Pi. We found that the salt tolerance of the transgenic rapeseed lines overexpressing BnaA05.NHX2 was significantly higher than that of wild type. Subcellular localization showed that BnaA05.NHX2 was localized on the tonoplast, and TEM combined with X-ray energy spectrum analysis revealed that the vacuolar Na+ concentrations of the BnaA05.NHX2-overexpressing rapeseed plants were significantly higher than those of wild type. The findings of this study will provide insights into the complexity of the BnaCPA family and a valuable resource to explore the in-depth functions of CPAs in B. napus.

An enhanced accuracy method for monitoring formation water salinity utilizing elemental spectroscopy logging

The accurate determination of formation water salinity is crucial for petroleum exploration and development, as it plays a significant role in determining reservoir parameters. The salinity of formation water affects physical parameters such as resistivity and Sigma, which are essential in calculating reservoir oil saturation. Therefore, this paper proposes an effective calculation method of formation water salinity based on elemental spectroscopy logging technology. The method starts by accurately calculating the formation chlorine (Cl) content through a combination of inelastic and capture energy spectrum analyses. Subsequently, a high-precision calculation model of formation water salinity is constructed by utilizing formation density and porosity information. Compared to the traditional oxide closure model, the joint bispectral method improves the calculation accuracy of Cl content by an order of magnitude and keeps the calculation error of formation water salinity within 2 g/L. The field logging example further demonstrates the high agreement between the calculated results of formation water salinity and laboratory analysis results, validating the accuracy of the joint bispectral method. This method is not affected by the mineral composition of the formation, making it suitable for a wide range of applications and highly versatile, which provides valuable technical support for the exploration and development of oil and gas in saltwater-bearing reservoirs.

Preparation of Cold Sprayed Titanium TA2 Coating by Irregular Powder and Evaluation of Its Corrosion Resistance

Titanium coating on a steel substrate by surface technology can improve the corrosion resistance of steel. In this paper, the titanium TA2 coating was deposited on X80 steel by cold spraying equipment with a low-cost irregular powder. The effects of the carrier gas temperature on the microstructure, microhardness, wear resistance, adhesion and corrosion resistance of titanium coatings, especially in a deep sea environment, were studied by methods of porosity analysis, thermal field emission scanning analysis, energy spectrum analysis, Vickers hardness tests, bonding strength tests, friction and wear tests and electrochemical tests. The results showed that as the carrier gas temperature increased from 300 °C to 900 °C, the porosity of the coating decreased to 0.93%, and the hardness and bonding strength of the coating increased to 247 HV0.5 and 46.7 MPa, respectively. With the increase in hydrostatic pressure from 0.1 MPa to 40 MPa, the dimensional blunt current density of the titanium coating with 0.93% porosity was still in the order of 10−7 A·cm−2 with the cast titanium TA2.

Investigation of variety of valence metal ions combinated novel Co‐rich high entropy oxides and its magnetic properties and microstructure

In this work, a series of five spinel-structured oxides were synthesized using a straightforward and effective solid-state methodology. Departing from the conventional design concept, we opted for the substitution of Fe3 + with five metal cations, all possessing trivalent average valence states and equivalent proportions. X-ray diffraction, scanning electron microscope, energy spectrum analyzer, vibrating sample magnetometer were used to detect the phase, micro-structure, element distribution, magnetism of the samples, respectively. The test results show that samples have the spinel structure (Fd3(_)m), and the element composition and distribution are the same as expected. The test results of magnetic properties reveal that these five samples exhibit the properties of soft magnetic materials. The maximum adjustment range of saturation magnetization (Ms) is increased from 23.5 emu/g to 34.8 emu/g by adjusting the elemental composition. Besides, the maximum adjustment range of coercivity (Hc) is increased from 11 Oe to 60 Oe. Furthermore, these materials exhibit a low remanent magnetization ratio, indicating that high-entropy oxides with spinel structures are highly sensitive to changes in an applied magnetic field. The high-entropy oxide is a new material with great prospect. It creates new possibilities for the design of magnetic materials.

Functionalized Cerium Dioxide Nanoparticles with Antioxidative Neuroprotection for Alzheimer's Disease.

Oxidative stress induced reactive oxygen species (ROS) and aggregation of amyloid β (Aβ) in the nervous system are significant contributors to Alzheimer's disease (AD). Cerium dioxide and manganese oxide are known as to be effective and recyclable ROS scavengers with high efficiency in neuroprotection. A hollow-structured manganese-doped cerium dioxide nanoparticle (LMC) was synthesized for loading Resveratrol (LMC-RES). The LMC-RES were characterized by TEM, DLS, Zeta potential, and X-ray energy spectrum analysis. We also tested the biocompatibility of LMC-RES and the ability of LMC-RES to cross the blood-brain barrier (BBB). The antioxidant effects of LMC-RES were detected by SH-SY5Y cells. Small animal live imaging was used to detect the distribution of LMC-RES in the brain tissue of AD mice. The cognitive abilities of mice were tested by water maze and nesting experiments. The effects of LMC-RES in reducing oxidative stress and protecting neurons was also explored by histological analysis. The results showed that LMC-RES had good sustained release effect and biocompatibility. The drug release rate of LMC-RES at 24 hours was 80.9 ± 2.25%. Meanwhile, LMC-RES could cross the BBB and enrich in neurons to exert antioxidant effects. In Aβ-induced SH-SY5Y cells, LMC-RES could inhibits oxidative stress through the Nrf-2/HO-1 signaling pathway. In AD model mice, LMC-RES was able to reduce ROS levels, inhibit Aβ-induced neurotoxicity, and protect neurons and significantly improve cognitive deficits of AD mice after drug administration. LMC-RES can effectively across the BBB, reduce oxidative stress, inhibit Aβ aggregation, and promote the recovery of neurological function.

Occurrence and transformation behaviour of silicon-bearing minerals during high silicon coal combustion from Yunnan Province, China

To understand the mineralogical characteristics and transformation behaviours of silicon-bearing minerals during coal combustion, seven typical high silicon (high-Si) coals and two high-Si fly ashes generated from high-Si coal-fired power plants were chosen. The coals were first treated by a method of low temperature ashing and the float-sink test for heavy minerals separation. Subsequently, low temperature ashes (LTA), light mineral fractions (LM), heavy mineral fractions (HM), and fly ashes from coal-fired power plants were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) combined with energy spectrum analysis (EDX), X-ray fluorescence spectrometry (XRF), and simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC).The results show that The mineral compositions in the LTA and LM are almost the same and majorly composed of quartz, kaolinite, calcite, dolomite, daphnite, chlorite-serpentine, pyrite, and anatase. The mineral compositions identified in the HM are clearly different from those in the LTA and LM. Pyrite, fluorapatite, anatase, siderite, dolomite and a plenty of silicate minerals including quartz, clinochlore, daphnite, chlorite, and chamosite are found in the HM. Chlorite is a quite common mineral in the HM with different shapes, including schistose, long tetragonal prism, cylindrical, block-shaped, and near-spherical, can be identified. The minerals identified in the fly ashes from the high-Si coal-fired power plants include quartz, mullite, and hematite. The mullite in the fly ashes is derived from the transformations of quartz, kaolinite, and chlorite in the coals. The quartz in the fly ash is mainly derived from the unchanged quartz in coal and a secondary origin from the SiO2-Al2O3 phase transformation. The high-Si fly ash with the size fraction of 38.5–74 μm contains the highest SiO2 content.

A study on microstructure evolution and mechanical properties of PVD TiAlN/TiAlCrSiN deposited on Re doped Ti(C,N)-based cermets

Re doped TiCN-based cermet substrates were prepared and coated with bilayer TiAlN/TiAlCrSiN to investigate the influencing mechanism of Re on structural evolution and mechanical performance of substrates and coatings. The results showed the grain size of hard phase particles decreased with the increase of Re content. The existence form of Re in cermets was characterized by high resolution transmission electron microscope (HRTEM) and energy spectrum analysis (EDS). Conclusions could be drawn that Re existed in solid solution and free state. Meanwhile, fcc-Co expanded to form hcp-Co structure, and twins was detected. According the generalized stacking fault energy (GSFE) curves calculated by first principles, it showed that the dissolution of Re into Co reduced the stable SFE γsf, unstable twinning SFE γut and twinning SFE γtsf of fccCo, promoting the formation of hcp-Co and twins. Cermets containing 0 wt% Re exhibited the strong preferred textures of {001}. However, the preferred orientation was obviously weakened in cermets containing 5 wt% Re, which indicated Re added into ceramic metals could restrain the preferred growth of {001} textures. The nanoindentation curves showed coatings on substrates with 5 wt% Re had the highest nanohardness value of 31.258GPa, which attributed to Re diffusion into TiAlCrSiN/TiAlN and refinement of core-rim grains. However, it was found that coatings on cermets with 5 wt% Re showed the lowest bonding strength due to the huge lattice structural difference between fcc-TiAlCrSiN and hcp-co substrate. In conclusion, bilayer TiAlCrSiN/TiAlN coatings deposited on TiCN-based cermets with 3 wt% Re possessed the best comprehensive performance, combining the various factors such as nanohardness, surface roughness, bonding strength and wear resistance.

Observed oceanic response to Tropical Cyclone Amphan (2020) from a subsurface mooring in the Bay of Bengal

Upper ocean responses to the super Tropical Cyclone (TC) Amphan and modulation of energy dissipation by internal tides were investigated using in situ observations from a subsurface mooring in Bay of Bengal (BoB). The observations showed that the entire observed water column (150–800 m) cooled significantly, up to a maximum of 2 ℃, and salinity increased significantly at 150–200 m within one week after the TC, mainly due to the TC-induced upwelling. Dynamic response was characterized by strong near-inertial oscillation above 120 m. The near inertial waves (NIWs) had a maximum velocity and kinetic energy at 112.6 m, about 0.34 m/s and 59.5 J/m3, respectively. The energy spectrum and bicoherence analysis indicated that, the nonlinear wave-wave interaction between NIWs (f) and semi-diurnal tide (D2), as well as the self-interaction of NIWs were enhanced after the passage of TC. The nonlinear wave-wave interaction processes were able to transfer energy to higher mode internal waves, thus accelerating energy attenuation. Hence, the observed e-folding time for near-inertial kinetic energy (6.2 days) was only 41 % of the theoretical e-folding time. This study provided a new evidence for the mechanism of energy dissipation of NIWs and semi-diurnal tide during a TC condition in the southern BoB.

Wettability between Titanium‐Containing Steels and TiC Ceramic Substrate

TiC particles, known for their extremely high hardness, are commonly used in metal‐matrix composite to enhance wear resistant. Precipitating TiC particles during the solidification stage of steel proves to be an effective method for improving product properties. Herein, TiC particles are determined to precipitate during the solidification process of titanium‐containing steels (Ti>0.3 wt%) through in situ observation experiment and energy spectrum analysis. To investigate the crucial factor of wettability, which significantly affects mechanical properties, the wetting experiments between TiC substrates (15 × 15 × 2 mm) and the steel specimens (Φ3 × 3 mm) with different titanium contents (0.01, 0.31, and 0.68 wt%) are simultaneously conducted employing a modified sessile drop method, combining with an electron probe microanalyzer. The results reveal that the molten steel infiltrates into the TiC substrate along its interconnected internal pores, driven by capillary force, with elements diffusion occurring and no reaction products are found in this process. Thermodynamic calculations confirm that TiC has a higher solubility in liquid steel compared to TiN, thus validating the superior wettability of TiC–steel system over the TiN–steel system. These findings provide valuable insights for studying wettability between TiC particles and high‐titanium steel, as well as for designing high‐titanium wear‐resistant steel compositions.

In situ formation mechanism of the honeycomb structure of a vitrified-bond diamond composite

Vitrified-bond diamond composites are materials commonly used for grinding wheels in the grinding process of silicon wafer production. In this study, the mechanism of the in situ honeycomb structure formation in the sintering process of composite materials was explored by changing the binder content without adding a pore-forming agent.The results show when the content of vitrified bond is 55 wt%, the in situ honeycomb structure forms, resulting in a porosity of 60.68 % and bending strength of 23.03 MPa.The X-ray diffraction (XRD), Raman spectroscopy (RS), and thermogravimetry-differential thermal analysis (TG-DTA) results show that no graphitization of diamond grain occurs during sintering. The bonding ability between the vitrified bond and diamond grain, along with the microstructure of vitrified-bond diamond composites, was studied using scanning electron microscopy (SEM). Moreover, the results of energy spectrum analysis (EDS) show that the diffusion and segregation of Na at the interface between the diamond particles and the vitrified bond improve the bonding strength, and the vitrified bond can effectively bond with the diamond particles. Finally, the formation mechanism of the honeycomb structure was elucidated using the surface and interface sintering theory.

Effect on mechanical properties and microstructure of high-strength eco-friendly concrete with waste glass powder-eggshell particles

Waste glass and discarded eggshells are common solid waste materials. In order to explore a new type of high-strength eco-friendly concrete, waste eggshell particles (ESP) combined with waste glass powder (GP) to replace the same mass of cement was used to prepare waste eggshell particles-waste glass powder concrete (ESGPC) in this study. The compressive strength and splitting strength of the specimens were tested using a universal testing machine. Meanwhile, the NMR technique was applied to test the pore structure of the specimens, the scanning electron microscope was used to investigate the microscopic morphology of the hydration products, and the distribution of GP and ESP in the specimens was investigated by the energy spectrum analyzer. The modification mechanisms of GP and ESP on the workability and mechanical properties of ordinary high-strength concrete were summarized. The results showed that as the content of ESP-GP increased, the slump of fresh concrete gradually increased, the compressive strength and splitting tensile strength first increased and then decreased, and the best replacement rate of ESGPC was 20%; the porosity of concrete initially decreased and then increased, and the number of gel pores (<10 nm) and transition pores (10 nm∼100 nm) increased with the increase of ESP-GP content. When the substitution rate of ESGPC reaches 40%, there is a significant decrease in the number of macropores (>1000 nm) and capillary pores (100 nm∼1000 nm). After analysis by the grey entropy correlation comprehensive analysis method, it was discovered that the volume of transition pores had the strongest correlation with the compressive strength of ESGPC; ESP-GP formed an amorphous film to compensate for the characteristics of weak bond in the transition zone of concrete.

The Downward Transport of Strong Wind by Convective Rolls in a Mediterranean Windstorm

Abstract The devastating winds in extratropical cyclones can be assigned to different mesoscale flows. How these strong winds are transported to the surface is discussed for the Mediterranean windstorm Adrian (Vaia), which caused extensive damage in Corsica in October 2018. A mesoscale analysis based on a kilometer-scale simulation with the Meso-NH model shows that the strongest winds come from a cold conveyor belt (CCB). The focus then shifts to a large-eddy simulation (LES) for which the strongest winds over the sea are located in a convective boundary layer. Convection is organized into coherent turbulent structures in the form of convective rolls. It is their downward branches that contribute most to the nonlocal transport of strong winds from the CCB to the surface layer. On landing, the convective rolls break up because of the complex topography of Corsica. Sensitivity experiments to horizontal grid spacing show similar organization of boundary layer rolls across the resolution. A comparative analysis of the kinetic energy spectra suggests that a grid spacing of 200 m is sufficient to represent the vertical transport of strong winds through convective rolls. Contrary to LES, convective rolls are not resolved in the kilometer-scale simulation and surface winds are overestimated due to excessive momentum transport. These results highlight the importance of convective rolls for the generation of surface wind gusts and the need to better represent them in boundary layer parameterizations.

Updated results on the cosmic ray energy spectrum and composition from the GRAPES-3 experiment

Here, we present the updated results on the cosmic ray energy spectrum and composition analysis from the GRAPES-3 experiment over the energy range of 50 TeV to 1000 TeV since ICRC 2021. The simulation of cosmic ray showers was performed using the post-LHC high energy hadronic interaction model QGSJetII-04 and low energy hadronic model FLUKA. A detailed GEANT4 simulation of the GRAPES-3 muon telescope was performed. The composition was obtained by fitting simulated muon multiplicity distributions for proton, helium, nitrogen, aluminium, and iron primaries to the observed data. The energy spectrum connects to the direct measurements with a fairly good agreement in flux.

Study on corrosion perforation behavior of copper nickel alloy pipe during service in marine environment

A CuNi90/10 copper nickel alloy seawater pipeline experienced premature perforation and leakage during service in the marine environment. The reasons of perforation and leakage of CuNi90/10 copper nickel alloy pipe in seawater pipelines were studied through macroscopic morphology, chemical composition, metallographic structure, microscopic morphology, and energy spectrum analysis, the influencing factors and key points for anti-corrosion and leakage prevention were analyzed. The results show that the chemical composition, hardness, and grain size of the CuNi90/10 copper nickel alloy pipe with perforation leakage meet the standard requirements, and the composition, microstructure distribution in the perforation leakage and nearby areas are uniform. CuNi90/10 copper nickel alloy pipe undergoes erosion-corrosion and perforation near the straight pipe section (approximately 10 mm from the weld toe) on the inner arch side of the elbow. The high flow rate of the seawater on the inner arch side of the elbow generates significant shear stress on the alloy pipe wall; solid particles such as sediment in the seawater impact the alloy pipe wall, causing damage to the passivation film and local plastic deformation; and due to the protrusion of the weld joint near the elbow, the local micro-turbulence of the seawater is generated; Under the combined action of erosion and corrosion, premature perforation and leakage of the copper nickel alloy pipe are caused. In order to avoid premature perforation leakage of the copper nickel alloy during service in the marine environment, safety technical operating procedures should be strictly followed during use, such as controlling fluid flow rate, maintaining seawater flow in the early stages of the service to form a protective film, and reducing the content of solid particles (such as sediment) in the fluid, etc.

Effect of LaB6 addition on the in-situ synthesis of TiBx/TixNiy/TiC reinforced Ni-based composite coatings

The TiBx/TixNiy/TiC reinforced Ni60 composite coatings were successfully prepared on the surface of 35CrMoV substrate using the laser cladding technology by adding different content of LaB6 (0, 0.5, 1.5, 2.5 wt%) powders into the mixture of TC4 (Ti6Al4V) and Ni60 (94 wt% Ni60, 6 wt% TC4). The phase composition, microstructure, element distribution and chemical composition of the cladding layer were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) with energy spectrum analysis (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. The reinforced phases in the cladding layer were mainly composed of TiB2, TiC, TiB, Ti2Ni, NiTi and Ni3Ti. The addition of LaB6 did not affect the phase composition, but the grains are obviously refined and the distribution of Ni, Cr and Ti elements is uniform at the addition of 1.5 wt% LaB6 addition. The cladding layer obtained excellent tribological and mechanical performance with the addition of 1.5 wt% LaB6, and the hardness, average friction coefficient and wear volume of the cladding layer reach 808 HV1, 0.183, and 8943 μm3, respectively. The reasonable addition of LaB6 significantly improves the friction and mechanical properties of the cladding layer.

A simple synthesis of a core-shell structure PPy-Au nanocomposite for immunosensing of C-reactive protein

High-sensitivity C-reactive protein (hs-CRP) is an inflammatory biomarker and can accurately predict the development of cardiovascular disease (CVD). We synthesized a core-shell structure PPy-Au nanocomposite in situ by chemically oxidizing pyrrole (Py) with HAuCl4 and the produced Au nanoparticles realized the doping in the polymerization. Analysis of morphology and energy spectrum as well as electrochemical characterization confirmed the successful one-pot synthesis. The conductive polymers with porous structure provide abundant sites for anti-CRP binding and effectively enhanced the sensitivity of the label-free BSA/anti-CRP/PPy-Au/GCE immunosensor. Its analytical performance was observed using differential pulse voltammetry (DPV), with a linear range from 0.0005 to 60 μg mL−1 and a detection limit of 0.17 ng mL−1. The platform demonstrated satisfactory selectivity, stability, and reproducibility. To validate its clinical application, we detected CRP in human serum samples with a recovery rate of 101.00–105.95% and investigated the consistency of the developed method and immunoturbidimetry with a deviation between −1.2% and +3.2%, suggesting great potential for use in point-of-care testing (POCT).