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Full-Heusler alloys with earth-abundant elements exhibit high mechanical strength and favorable electrical transport behavior, but their high intrinsic lattice thermal conductivity limits potential thermoelectric application. Here, the thermoelectric transport properties of Fe-based Full-Heusler Fe2MAl (M = V, Nb, Ta) alloys are comprehensively investigated utilizing density functional theory. The results suggest that Fe2NbAl exhibits exceptionally low lattice thermal conductivity due to low phonon velocities and weakly bound Nb atoms. In Fe2NbAl, the underbonding of the Nb atoms leads large Grüneisen parameters and high anharmonic scattering rates of low-frequency acoustic phonon. Meanwhile, the high band degeneracy and large electrical conductivity lead to a maximum p-type power factor of 255.6 μW·K−2·cm−1 at 900 K. The combination of low lattice thermal conductivity and favorable electrical transport properties leads a maximum p-type dimensionless figure of merit of 1.7. Our work indicates Fe2NbAl, as a low-cost, environmentally friendly, is a potential high-performance p-type thermoelectric material. [ABSTRACT FROM AUTHOR]

Thermo‐electro‐magnetic materials with simultaneously large magnetocaloric (MC) and thermoelectric (TE) effects are the core part for designing TE/MC all‐solid‐state cooling devices. Compositing MC phase with TE material is an effective approach. However, the elemental diffusion and chemical reaction occurring at the two‐phase interfaces could significantly impair the cooling performance. Herein, Gd/Bi0.5Sb1.5Te3 (Gd/BST) composites were prepared by a low‐temperature high‐pressure spark plasma sintering method with an aim to control the extent of interfacial reaction. The reaction of Gd with the diffusive Te and the formation of GdTe nanocrystals were identified at the Gd/BST interfaces by the atomic‐resolution microscope. The formed BiTe' antisite defects and enhanced {000 l} preferential orientation in BST are responsible for the increased carrier concentration and mobility, which leads to optimized electrical properties. The heterogeneous interface phases, along with antisite defects, favor the phonon scattering enhancement and lattice thermal conductivity suppression. The optimized composite sintered at 693 K exhibited a maximum ZT of 1.27 at 300 K. Furthermore, the well‐controlled interfacial reaction has a slight impact on the magnetic properties of Gd and a high magnetic entropy change is retained in the composites. This work provides a universal approach to fabricating thermo‐electro‐magnetic materials with excellent MC and TE properties. [ABSTRACT FROM AUTHOR]

Using the AC electric field to induce the orientation of nonlinear conductive fillers in composites is an effective solution for alleviating electric field distortion in power modules. However, the mechanism by which the electric field affects the filler dynamic characteristics and the composites' electrical properties remains unclear. In this paper, the correlation between the microscopic dynamic processes of fillers and the macroscopic current amplitude was analyzed. The results show that the current increases rapidly (0 ∼ 173 s) and then slowly (173 ∼ 869 s) at 600 V mm−1, influenced by the rotation and attraction processes of the fillers. This demonstrates that the orientation stops at about 869 s and the filler orientation state is a key factor in determining the dielectric properties. Secondly, the global orientation evaluation index D for the filler network was proposed, which can also derive the minimum time and energy loss required for preparation. Finally, the impact of different filler orientations on the composites' conductivity was investigated. In the low electric field stress region, with the average carrier jump distance decreasing from 150.23 to 109.71 nm as the D increases from −0.93 to −0.05. On this basis, materials with nonlinear conductivity gradient distribution can be easily prepared. Before optimization, the electric field stress of the power module at the triple point was 35.79 kV. This composite can reduce the value to 15.42 kV, a decrease of 56.9%, while maintaining good electric field uniformity. [ABSTRACT FROM AUTHOR]

Nanostructured transition metal dichalcogenide MnSe2 has attracted much attention due to its fascinating magnetic properties. In this article, a series of MnSe2 nanoparticles with different particle sizes are successfully prepared by a facile top‐down method of solid‐state reaction combined with ball milling, and the effects of ball milling on the phase composition, microstructure and magnetic properties of the MnSe2 are systematically studied. The results show that pure MnSe2 microparticles are obtained by the solid‐state reaction, however, partial MnSe2 is decomposed after ball milling for 16 h. The average particle size of the MnSe2 gradually decreases with the increase of milling time. MnSe2 nanoparticles with average particle size approximately 65 nm are obtained after milling for 40 h. After milling, the antiferromagnetic MnSe2 nanoparticles exhibit weak ferromagnetic characteristics due to the surface effect and the microstrain induced by ball milling. The residual magnetization (Mr) and coercivity (Hc) of the sample gradually increase as the particle size decreases. The Mr and Hc of the sample milled for 40 h reach 70.13 × 10−4 emu g−1 and 67.47 Oe, respectively. [ABSTRACT FROM AUTHOR]

Currently, the most promising breakthrough to the main bottleneck of in-plane heat dissipation technology based on the Peltier effect is the development of high-performance thermoelectric (TE) films. Herein, a series of p-type Bi0.5Sb1.5Te3 (BST)/xFe-BST epoxy multilayer films (Fe nanoparticles (Fe-NPs)-BST (Fe-BST) layer x = 0, 1, 2, 3 and 4) were designed and prepared by inserting a magnetic layer into two TE layers. The metallic magnetic Fe-NP layers as electron carrier expressways were introduced into BST epoxy multilayer films to produce a high-speed conductive channel and extra interlayer magnetic scattering to improve the electrical transport performance of the BST epoxy multilayer films. The electrical conductivity of the BST/xFe-BST epoxy multilayer films is significantly increased due to a surge in carrier mobility. Magnetoresistance shows that the Fe-NP layer in BST/xFe-BST epoxy multilayer films is able to produce extra interlayer magnetic scattering (spin-dependent scattering and weak-localization pinning), suppressing the decrease of the Seebeck coefficient. As a result, the maximum power factor (2.29 × 10−3 W K−2 m−1) of BST/Fe-BST epoxy multilayer films increased by 139% compared to that of the BST epoxy multilayer film, and the maximum cooling temperature difference was enhanced by 1.2 times. The interlayer coupling between magnetic/TE layers is utilized to introduce a new effect of thermo-electro-magnetic coupling in this study, which endowed the thermoelectromagnetic films with certain magnetic properties and significantly enhanced TE conversion performance, providing a new way for the preparation of high-performance TE films. [ABSTRACT FROM AUTHOR]

Diffusion and occupancy of magnetic atoms in van der Waals (VDW) layered materials have significant impact on applications such as energy storage, thermoelectrics, catalysis, and topological phenomena. However, due to the weak VDW bonding, most research focus on in‐plane diffusion within the VDW gap, while out‐of‐plane diffusion has rarely been reported. Here, to investigate out‐of‐plane diffusion in VDW‐layered Bi2Te3‐based alloys, a Ni/Bi0.5Sb1.5Te3 heterointerface is synthesized by depositing magnetic Ni metal on a mechanically exfoliated Bi0.5Sb1.5Te3 (0001) substrate. Diffusion of Ni atoms across the Bi0.5Sb1.5Te3 quintuple layers is directly observed at elevated temperatures using spherical‐aberration‐corrected scanning transmission electron microscopy (STEM). Density functional theory calculations demonstrate that the diffusion energy barrier of Ni atoms is only 0.31–0.45 eV when they diffuse through Te3(Bi, Sb)3 octahedron chains. Atomic‐resolution in situ STEM reveals that the distortion of the Te3(Bi, Sb)3 octahedron, induced by the Ni occupancy, drives the formation of coherent NiM (M = Bi, Sb, Te) at the heterointerfaces. This work can lead to new strategies to design novel thermoelectric and topological materials by introducing magnetic dopants to VDW‐layered materials. [ABSTRACT FROM AUTHOR]

Fiber brushes with expanded graphite (EG) as a lubricant were successfully prepared. Compression properties of brushes filled with unbent fibers and bent fibers with different packing fractions were compared. Moreover, the friction and wear behaviors of the brushes with the same fiber packing fractions (17.5 vol%) but different EG volume contents were investigated. The effect of EG content on the tribological behavior of the fiber brush was analyzed according to the microstructure, debris, and worn surface of the brush and counterface disc. Results showed that both the elastic constant and compression strength of the brushes filled with bent fibers increased with an increase in packing fraction. Brushes filled with 17.5 vol% bent fibers had similar compression strength (2.69 MPa) but a lower elastic constant (150 N/mm) compared to the brush filled with 17.5 vol% unbent fibers (2.62 MPa and 425 N/mm). The friction coefficients and wear rates of the brushes decreased from 1.02 and 1.6 × 10−5 mm3/Nm to 0.25 and 0.28 × 10−5 mm3/Nm as the EG increased to a critical value (23.7 vol%). The worn surface and wear debris demonstrate that the wear mechanism of tin–bronze fiber brushes with EG sliding against brass discs transforms from adhesive wear to abrasive wear due to the formation of an EG lubricating film. [ABSTRACT FROM AUTHOR]

The complete product vibrational energy distribution from F+H2, CH4, C2H6 reactions was determined by the chemical laser grating selection (CLG) technique. Three important factors—vibrational relaxation and secondary reaction, rotational nonequilibrium, and superradiance were carefully investigated by time-resolved laser spectroscopy and analyzed by computer modeling. It was found that by using lower reactant pressure, these disadvantageous effects, which may have influenced the results of previous chemical laser studies, could be minimized or eliminated experimentally. It was also found that for these reactions, the accurate values of N2/N1 and N3/N2 could be obtained from the experiment or modeling calculation; in contrast, the value of N1/N0 was very high and was sensitive to vibrational relaxation and secondary reaction processes. In general, the results of the CLG method, at least for these reactions, are of the same degree of accuracy as those of the infrared chemiluminescence method. The rotational equilibrium assumption is still valid and can be used without apparent effect on the experimental results. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the strategy for management of urosepsis after extracorporeal shock wave lithotripsy (ESWL)., Methods: The clinical data were analyzed in 4 cases of urosepsis caused by ESWL during the period from January, 2008 to October 2011., Results: Two of the patients had kidney stones and two had ureteral stones. Analysis of urine bacterial culture revealed the presence of E. coli in 2 cases, Klebsiella pneumoniae in 1 case and Pseudomonas putida combined E. coli in 1 case. All the 4 patients were monitored for ECG, blood pressure and oxygen saturation, and received fluid replacement and anti-inflammatory therapy. The vital signs of the patients became stable after 5-11 days (mean 6.75 days). Three patients underwent ureteroscopic lithotripsy, and 1 patient had emergency ureteral stent indwelling. All the 4 patients were cured and discharged., Conclusion: ESWL is more likely to cause urosepsis in patients with ureteral stones and urinary infection, for which early nonsurgical interventions should be administered immediately after the diagnosis is established.

Objective: To evaluate the factors affecting the efficacy of extracorporeal shock wave lithotripsy (ESWL) and establish a model for predicting the success rate of a single ESWL session in the treatment of single renal calculus., Methods: Between January 2008 and February 2010, 325 patients underwent ESWL monotherapy and were followed up for at most 3 months. The correlations between the outcome of a single ESWL session and the patients' age, gender, body mass index (BMI), disease duration, pretreatment renal colic, hematuria, urinary irritation symptoms, stone location, stone laterality, stone length and stone width were analyzed. The statistically significant factors identifies were further analyzed by multivariate logistic regression, and the predictive model was established., Results: The stone-free rate of ESWL was 76.9%. Univariate analysis found that the patients' age, stone laterality, stone location, disease duration, pretreatment hematuria, stone length and width all significantly affected the outcome of the treatment. Logistic regression analysis indicated the factors including disease duration, pretreatment hematuria, stone length and stone width determined the success rate of the treatment. Hosmer and Lemeshow Test showed a good fitting of the predictive model (Χ(2)=18.144, df=8, P=0.168) with an overall accuracy of 87.4%., Conclusion: Disease duration, pretreatment hematuria, stone length and width are independent factors affecting the outcome of a single ESWL session for single renal calculus.

Objevtive: To analyze the complications of extracorporeal shock wave lithotripsy (ESWL) for treatment of lower urinary tract stones and identify the factors contributing to the complications., Methods: We retrospectively analyzed the postoperative complications of ESWL in 83 patients with lower urinary tract stones and their association with the patients' age, height, body weight, body mass index (BMI), stone features, shock wave times, and shock wave energy., Results: Of the 83 cases treated with ESWL, 72.3% (60 cases) showed gross hematuria, 27.7% (23 cases) complained of pain, and 25.3% (21 cases) had both pain and gross hematuria. None of the patients reported vomiting, skin rash, flatulence, gastrointestinal bleeding or other complications. Patients with postoperative gross hematuria, pain, and both had significantly greater stone length, stone width and more shock body times than those without these complications (P<0.01 or P<0.05). Patients with gross hematuria had significantly lower height than those without complications (P<0.05)., Conclusion: The common complications of ESWL for lower urinary tract stones include hematuria and pain. The patient's height, stone length, stone width and shock times are important factors contributing to these postoperative complications.