NiTi//Al2O3 composites have many advantages such as large elasticity, superior hardness and wear resistance. But there is little information available about the novel adhesion strength, fracture ...mechanism and interfacial bonding of NiTi//Al2O3 composites at the atomic scale. Therefore, the work of adhesion (Wad), interfacial energy (γ) and electronic structure of NiTi(111)//α-Al2O3(0001) interfaces have been calculated using first-principles calculations. For the models with the same stacking site, O-terminated interfaces have larger Wad and smaller γ than Al-terminated interfaces. For the models with same termination, the stability of Ni(Ti)-Al interfaces decreases with the order of HCP > MT > OT, while the stability of Ni(Ti)-O interfaces decreases as MT > HCP > OT. The Ti-O-MT interface belongs to the most stable interfacial configuration with the smallest interface energy among all studied interfaces. Using Griffith's theory, it is predicted that the mechanical failure of NiTi//α-Al2O3 interfaces are inclined to initiate in the interior of NiTi bulk or at the interface rather than Al2O3 side in most cases. Furthermore, density of states and electron density difference analysis indicate that the dominant interfacial adhesion mechanism for the NiAl interfaces is the formation of mainly metallic TiAl and NiAl bonds, while the TiO interface exhibits mixed covalent/ionic character with higher interfacial binding strength.
The interface energies of Ni-Al2-HCP2 and Ti-Al2-HCP2 configurations at 298 K are increased with the increasing of the partial pressure of oxygen, indicating their thermodynamic stabilities are decreased in the oxygen rich condition. Meanwhile, the Ni-O-MT and Ti-O-MT interfaces are stabilized by increasing the partial pressure of oxygen. Display omitted
•NiTi//α-Al2O3 interfaces were studied to reveal their adhesion strength, fracture mechanism and interfacial bonding.•Ti-O-MT interface is the most stable interfacial configuration with the smallest interface energy of 2.07 J/m2.•The mechanical failure are inclined to initiate in the interior of NiTi bulk rather than the interface.
In situ small-sized TiB2/Al-4.5Cu composites with high strength and good ductility were prepared via an ultrasound assisted re-melting and diluting (RD) approach in this research. The experimental ...results showed that small-sized TiB2 particles with an average size of 100 nm were synthesized in the metal-salts reaction. Both the Al-TiB2 mater composite and TiB2/Al-4.5Cu composites with homogeneous microstructures were obtained due to the effects of ultrasound. The α-Al grains in Al-4.5Cu alloy transferred from large-sized dendrite to small-sized spherical in morphology by adding the TiB2 particles. Compared with the original Al-4.5Cu alloy, the 5 wt% TiB2/Al-4.5Cu composites exhibited the best comprehensive mechanical properties, and the yield strength, ultimate tensile strength and elongation were improved by 39.7%, 39.9%, and 7.9%, respectively. Furthermore, the mechanisms of the improved mechanical properties, including the strength and ductility, of the composites were discussed.
•The average of in situ formed TiB2 particles was about 100 nm.•Ultrasound leaded to the uniform distribution of TiB2 particles in the matrix.•Al-Cu alloy matrix was refined by TiB2.•The strength and ductility of composites were improved simultaneously.
The carbon supported iron selenide catalysts (FeSe2/C) were prepared with various selenium to iron ratios (Se/Fe), namely, Se/Fe = 2.0, 2.5, 3.0, 3.5 and 4.0, through facile microwave route by using ...ferrous oxalate (FeC2O4·2H2O) and selenium dioxide (SeO2) as precursors. Accordingly, effects of Se/Fe ratio on the crystal structure, crystallite size, microstructure, surface composition and electrocatalytic activity for oxygen reduction reaction (ORR) of FeSe2/C in an alkaline medium were systematically investigated. The results revealed that all the FeSe2/C catalysts obtained with the Se/Fe ratios of 2.0–4.0 exhibited almost pure orthogonal FeSe2 structure with the estimated mean crystallite sizes of 32.9–36.2 nm. The electrocatalytic activities in potassium hydroxide solutions were higher than those in perchloric acid solutions, and two peak potentials or two plateaus responded to ORR were observed from cyclic voltammograms and polarization curves, respectively. The ORR potentials of 0.781–0.814 V with the electron transfer numbers of 3.3–3.9 at 0.3 V could be achieved as the Se/Fe ratios varied from 2.0 to 4.0. The Fe and Se were presented at the surface of FeSe2/C upon further reduction on FeSe2. The Se/Fe ratios slightly influenced the degree of graphitization in carbon support and the amount of active sites for ORR.
Atmospheric plasma spraying (APS) was taken to fabricate the NiCrAlY coating. The corrosion-wear properties of NiCrAlY coating was measured respectively under deionized water, artificial seawater, ...NaOH solution and HCl solution. Experimental results presented that the as-sprayed NiCrAlY coating consisted of Ni
Al, nickel-based solid solution, NiAl and Y
O
. In deionized water, the coating with the lowest corrosion current density (
) of 7.865 × 10
A/cm
was hard to erode. Meanwhile, it presented a lower friction coefficient and the lowest wear rate. In HCl solution, NiCrAlY coating gave the highest corrosion current density (
) of 3.356 × 10
A/cm
and a higher wear rate of 6.36 × 10
mm
/Nm. Meanwhile, the emergence of Al(OH)
on the coating surface could reduce the direct contact between the counter ball and sample effectively, which was conducive to the lowest friction coefficient of 0.24.
Using zirconia toughened alumina (ZTA) particles and Ni-Ti complex powders as raw materials, high-Cr cast iron reinforced by ZTA particles was prepared by an infiltration casting process. A ...continuous transition layer formed at the interface between ZTA particles and the Cr15 matrix, which proves that there is strong metallurgical interfacial bonding at the interface. The phases in the Ni-Ti layer of the ZTA
/Fe composite were preserved compared with the microstructure of sintered ZTA ceramic preform. The hardness of the Ni
Ti, TiO and AlNi
Ti phases in the interfacial transition layer was measured by the nano-indentation method, which is 12.5 GPa, 16.1 GPa and 9.2 GPa, respectively. The three-body wear resistance of the composite reached 12.6 times that of high-Cr cast iron.
By performing a high-throughput first principles calculations on works of adhesion of total 468 different NiTi2/Al2O3 interfaces, eight interfacial configurations (Ni1–O, Ni2–O, Ti1–O, Ti2–O, ...Ni1–Al2, Ni2–Al1, Ni2–Al2 and Ti2–Al2) belonging to metal–metal and metal–oxygen interfaces are obtained due to their high adhesive strengths. The predicted work of adhesion of metal–oxygen interfaces is higher than 8.80 J/m2, and that value of metal–metal interfaces varies in the range from 2.39 J/m2 to 3.59 J/m2. The interfacial energies of the eight interfaces are obtained at different temperatures (298 K and 1000 K) by varying the chemical potential of oxygen atom. At room temperature, the metal–oxygen interfaces possess the lower interfacial energies and thus the higher thermodynamic stability than those of metal–metal interfaces regardless of the partial pressure of oxygen gas. At high temperature, metal–oxygen interfaces are still favored under O-rich condition, but the metal–metal interfaces are greatly stabilized in case of low oxygen partial pressure. The predicted tensile strengths of metal–oxygen interfaces are all above 10 GPa, and those of for metal–metal interfaces are below this value. For all investigated metal–metal and metal–oxygen NiTi2/Al2O3 interfaces, the mechanical failure is always initiated in the NiTi2 phase proximity to the interface resulted from the breaking of Ni–Ti/Ti–Ti bonds in the first principles tensile test.
The effect of hot rolling with different rolling deformations on the microstructure evolution and improvement of mechanical properties of the novel Al–Zn–Mg–Cu alloy are investigated via optical ...microscope (OM), scanning electron microscope (SEM), electron backscattered diffusion (EBSD) and transmission electron microscope (TEM). The findings showed that the equiaxed grains with low dislocation density gradually elongate to become fibrous with high dislocation density as hot rolling deformation growing, and the dynamic dissolution of precipitations occurs at the grain boundaries of small dynamic recrystallization (DRX) grains. Dislocation entanglement is formed when a high density of dislocation is clearly visible following various rolling deformations. Dislocation cells could evolve into sub-grains, and ultimately become recrystallized grains as a result of continuous energy absorption. The percentage of low angle grain boundaries (LAGBs) with varying rolling deformation increases swiftly then declines slightly which linked to more deformed grains and sub-grains, as well as less recrystallized grains. High angle grain boundaries (HAGBs), however, show the opposite pattern. Ultimate tensile strength (UTS) and yield strength (YS) of the alloys reach peaks at deformation of 90% (UTS: 620.0 MPa, YS: 583.7 MPa). Which is predominantly attributed to the texture enhancement, grain refinement, and pinning effect of Al3(Sc, Zr, Ti) particles of L12 structure on the grain boundaries and dislocations.
Background
To explore the clinical and laboratory features, therapy and prognosis of Kikuchi–Fujimoto disease (KFD) in the cervical region.
Methods
We retrospectively reviewed the medical records of ...134 patients who were diagnosed and treated with KFD from January 2000 to May 2022 in Fujian Medical University Union Hospital (Fujian, China). Their clinical characteristics, affected lymph node size, imaging examinations, and laboratory study results were analyzed.
Results
The mean patient age was 24.9 years, and the male–female ratio was 1:1.73. Fever (55.2%, n = 74) was the most common clinical manifestation. Leukopenia (49.3%) was the commonest reported laboratory abnormality. A majority (65.7%) of the 134 patients presented with bilateral nodal involvement.
Conclusion
KFD should be considered as a possible diagnosis in a female patient under the age of 30 presenting with cervical lymphadenopathy, fever, leukopenia, and elevated LDH.
Level of Evidence
4.
Kikuchi–Fujimoto disease is a rare but increasingly recognized cause of cervical lymphadenopathy. Otorhinolaryngologists must be aware of the manifestations of this disease, clinical course, and the potential for confusion with other diseases.
In psychopharmacology, treatment with psychotropic drugs is often suboptimal, mainly because of the high interindividual variability in pharmacokinetic properties. Therapeutic drug monitoring (TDM) ...can be a valuable tool for monitoring the individual effects of a prescribed dosage in a patient, and it facilitates antipsychotic treatment by increasing the effectiveness and safety of drugs and by reducing treatment costs. The aim of this study was to develop and validate an ultrafast liquid chromatography (UFLC) method with tandem mass spectrometric detection for the measurement of 16 antipsychotics and antidepressants in human plasma samples for TDM or other applications.
The method was developed to replace traditional methods using the solid-phase extraction of proteins precipitated with methanol/acetonitrile containing 0.1% formic acid. Quantitative analysis was performed by UFLC combined with a tandem mass spectrometer using a Synergy 3u-Hydro-RP (2.0 × 50 mm, 3 μm) column with a mobile phase consisting of 0.1% formic acid and acetonitrile.
A simple, fast, and sensitive UFLC-tandem mass spectrometry method for the simultaneous measurement of commonly used antipsychotics (aripiprazole, chlorpromazine, paliperidone, quetiapine, risperidone, ziprasidone, clozapine, and olanzapine), antidepressants (citalopram, escitalopram, mirtazapine, fluoxetine, paroxetine, sertraline, venlafaxine plus O-desmethylvenlafaxine, and fluvoxamine) and an antidementia drug (donepezil) has been developed. The total run time of the chromatographic separation was 6.0 minutes. The precision and accuracy varied from 0.90% to 14% and from 88.5% to 118%, respectively. A 6-point standard curve covering the clinically relevant ranges with a power function fit was applied for calibration. Ion suppression due to matrix effects and the internal standards were investigated. Their recoveries varied from 89% to 110%.
This new validated method fulfills all criteria for TDM and was successfully applied in the routine TDM of antipsychotics and antidepressants at the First Affiliated Hospital of Kunming Medical University.
We presented a theoretical study for the structural, mechanical, and thermophysical properties of the precipitates in 2xxx series aluminum alloy by applying the widely used density functional theory ...of Perdew-Burke-Ernzerhof (PBE). The results indicated that the most thermodynamically stable structure refers to the Al3Zr phase in regardless of its different polymorphs, while the formation enthalpy of Al5Cu2Mg8Si6 is only -0.02 eV (close to zero) indicating its metastable nature. The universal anisotropy index of AU follows the trend of: Al2Cu > Al2CuMg ≈ Al3Zr_D022 ≈ Al20Cu2Mn3 > Al3Fe ≈ Al6Mn > Al3Zr_D023 ≈ Al3Zr_L12 > Al7Cu2Fe > Al3Fe2Si. The thermal expansion coefficients (TECs) were calculated based on Quasi harmonic approximation (QHA); Al2CuMg shows the highest linear thermal expansion coefficient (LTEC), followed by Al3Fe, Al2Cu, Al3Zr_L12 and others, while Al3Zr_D022 is the lowest one. The calculated data of three Al3Zr polymorphs follow the order of L12 > D023 > D022, all of them show much lower LTEC than Al substance. For multi-phase aluminum alloys, when the expansion coefficient of the precipitates is quite different from the matrix, it may cause a relatively large internal stress, or even produce cracks under actual service conditions. Therefore, it is necessary to discuss the heat misfit degree during the material design. The discrepancy between a-Al and Al2CuMg is the smallest, which may decrease the heat misfit degree between them and improve the thermal shock resistant behaviors.
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