•SLM fabricated nickel based superally K536 is studied, which is scarce in present reports.•Tensile performance at room and elevated temperatures (400–700 °C) of SLM K536 and its wrought counterparts ...are compared and analyzed.•The anisotropy of tensile and fatigue performances at room and elevated temperatures are investigated.•The surface slippage and the internal facet are the main characteristics of crack initiation at elevated temperatures to SLM K536 specimens.
Additive manufacturing techniques show more and more utilization potentialities in today’s aviation industry. In order to ensure safe operation of additive manufactured parts, it is important to have their mechanical properties well-characterized and assessed. In this study, elevated temperature tensile and fatigue performances of one selective laser melting (SLM) fabricated nickel based superalloy named K536 are investigated. A series of tensile tests at room and 400–700 °C temperature range and stress-controlled fatigue tests at 400 °C and 600 °C are employed. Effects of building orientation and temperature on tensile and fatigue properties are analysed. Scanning electron microscopy is used to examine the fracture surfaces of fatigue specimens to qualify the failure mechanism and crack initiation sites. The SLM K536 exhibits higher tensile strength in contrast with the wrought alloy at different tested temperatures. It is found that the anisotropy of monotonic tensile and fatigue properties is not significant. The scatter of fatigue data in the near-fatigue limit region shows more serious at 400 °C than 600 °C, indicating that a more conservative life prediction method will be suitable to ensure safety at lower temperature. The surface slippage and the internal facet are the main characteristics of crack initiation at elevated temperatures to SLM K536 specimens with shorter fatigue life and longer fatigue life, respectively.
In this study, we prepare a kind of solid polymer electrolyte (SPE) based on
N-ethyl-
N′-methyl imidazolium tetrafluoroborate (EMIBF
4), LiBF
4 and poly(vinylidene difluoride-co-hexafluoropropylene) ...P(VdF-HFP) copolymer. The resultant SPE displays high thermal stability above 300
°C and high room temperature ionic conductivity near to 10
−3
S
cm
−1. Its electrochemical properties are improved with incorporation of a zwitterionic salt 1-(1-methyl-3-imidazolium)propane-3-sulfonate (MIm3S). When the SPE contains 1.0
wt% of the MIm3S, it has a high ionic conductivity of 1.57
×
10
−3
S
cm
−1 at room temperature, the maximum lithium ions transference number of 0.36 and the minimum apparent activation energy for ions transportation of 30.9
kJ
mol
−1. The charge–discharge performance of a Li
4Ti
5O
12/SPE/LiCoO
2 cell indicates the potential application of the as-prepared SPE in lithium ion batteries.
End-point free energy calculations as a powerful tool have been widely applied in protein–ligand and protein–protein interactions. It is often recognized that these end-point techniques serve as an ...option of intermediate accuracy and computational cost compared with more rigorous statistical mechanic models (e.g., alchemical transformation) and coarser molecular docking. However, it is observed that this intermediate level of accuracy does not hold in relatively simple and prototypical host–guest systems. Specifically, in our previous work investigating a set of carboxylated-pillar6arene host–guest complexes, end-point methods provide free energy estimates deviating significantly from the experimental reference, and the rank of binding affinities is also incorrectly computed. These observations suggest the unsuitability and inapplicability of standard end-point free energy techniques in host–guest systems, and alteration and development are required to make them practically usable. In this work, we consider two ways to improve the performance of end-point techniques. The first one is the PBSA_E regression that varies the weights of different free energy terms in the end-point calculation procedure, while the second one is considering the interior dielectric constant as an additional variable in the end-point equation. By detailed investigation of the calculation procedure and the simulation outcome, we prove that these two treatments (i.e., regression and dielectric constant) are manipulating the end-point equation in a somehow similar way, i.e., weakening the electrostatic contribution and strengthening the non-polar terms, although there are still many detailed differences between these two methods. With the trained end-point scheme, the RMSE of the computed affinities is improved from the standard ~ 12 kcal/mol to ~ 2.4 kcal/mol, which is comparable to another altered end-point method (ELIE) trained with system-specific data. By tuning PBSA_E weighting factors with the host-specific data, it is possible to further decrease the prediction error to ~ 2.1 kcal/mol. These observations along with the extremely efficient optimized-structure computation procedure suggest the regression (i.e., PBSA_E as well as its GBSA_E extension) as a practically applicable solution that brings end-point methods back into the library of usable tools for host–guest binding. However, the dielectric-constant-variable scheme cannot effectively minimize the experiment-calculation discrepancy for absolute binding affinities, but is able to improve the calculation of affinity ranks. This phenomenon is somehow different from the protein–ligand case and suggests the difference between host–guest and biomacromolecular (protein–ligand and protein–protein) systems. Therefore, the spectrum of tools usable for protein–ligand complexes could be unsuitable for host–guest binding, and numerical validations are necessary to screen out really workable solutions in these ‘prototypical’ situations.
•Laser power bed fusion of Al-12Si alloy was conducted under static magnetic field.•A cellular structure within the molten pool was homogenized and refined.•The columnar-to-equiaxed transition was ...promoted under magnetic field.•Mechanical properties of high strength and large ductility were achieved.•The ductility-strength combination is attributed to the microstructure evolution.
Rapid cooling and solidification during laser additive manufacturing (LAM) can produce ultra-fine microstructure with higher strength. However, the non-uniform cell/grain structure can easily result in early stress concentration and fracture during deformation, which remains a major challenge for the LAM field. Using Al-12Si as the model alloy, we employed the external static magnetic field (SMF) to modulate the laser powder bed fusion process (L-PBF), demonstrating a uniform microstructure with a refined cell structure. The mechanical properties show that the SMF can produce a combination of high tensile strength of 451.4 ± 0.5 MPa and large uniform elongation of 10.4% ± 0.79%, which are superior to those of previously-reported Al-Si alloys with post-treatment or element alloying. The mechanism analysis based on multi-scale simulation reveals the determining role of SMF in rapid solidification, and this method is applicable to the microstructure control of other metallic materials during LAM.
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The objective of the present study was to investigate the effects of dietary supplemental Zinc (Zn) source and level on antioxidant ability and fat metabolism-related enzymes of broilers. Dietary ...treatments included the Zn-unsupplemented corn-soybean meal basal diet (control) and basal diets supplemented with 60, 120, or 180 mg Zn/kg as Zn sulfate, Zn amino acid chelate with a weak chelation strength of 6.5 quotient of formation (Qf) (11.93% Zn) (Zn-AA W), Zn proteinate with a moderate chelation strength of 30.7 Qf (13.27% Zn) (Zn-Pro M), or Zn proteinate with an extremely strong chelation strength of 944.0 Qf (18.61% Zn) (Zn-Pro S). The results showed that dietary supplemental Zn increased (P < 0.01) Zn contents in the liver, breast, and thigh muscles of broilers, and up-regulated mRNA expressions of copper and Zn containing superoxide dismutase (CuZnSOD) and metallothioneins (MT) in the liver (P < 0.01) and thigh muscle (P < 0.05), and also enhanced (P < 0.05) CuZnSOD activities in the breast and thigh muscles, which exerted antioxidant ability and a decreased malondialdehyde (MDA) level in the liver (P < 0.01) and breast and thigh muscles (P < 0.05) of broilers. Furthermore, supplemental Zn increased activities of malate dehydrogenase (MDH) and lipoprotein lipase (LPL) in the abdominal fat (P < 0.05), and fatty acid synthetase (FAS) and LPL in the liver (P < 0.01), which were accompanied with up-regulation (P < 0.01) of the mRNA expressions levels of these enzymes in the abdominal fat and liver of broilers. Dietary Zn source, and an interaction between Zn source and level, had no effects on any measurements. It is concluded that dietary Zn supplementation improved Zn status and resulted in promoting antioxidant ability and activities and gene expressions of fat metabolism-related enzymes of broilers regardless of Zn source and level, and the addition of 60 mg Zn/kg to the corn-soybean meal basal diet (a total dietary Zn of approximately 90 mg/kg) was appropriate for improving the above aspects of broilers.
This paper presents the magnetospheric multiscale (MMS) observations of three flux ropes (FRs) sequentially in a reconnection exhaust at Earth's magnetopause. Three active X‐lines, which are ...responsible for the formation of these FRs, were also detected by MMS, providing strong evidence that the FRs were generated by multiple X‐line reconnection. We find that the core field inside the FRs considerably affects the Hall current in the adjacent X‐lines. The intense core field of the FRs deflected the electron outflow jet, forming the electron‐scale Hall magnetic field on the magnetosheath side. Additionally, an active secondary reconnection was observed at the center of one FR. This secondary reconnection split the FR into two smaller FRs and produced sharp density gradients and intense fluctuations of electric field and current within the FR. These observations advance the understanding of the formation and evolution of FRs during multiple X‐line reconnection at magnetopause.
Plain Language Summary
Flux transfer event (FTE) is generally explained as the flux rope (FR) generated by multiple X‐line reconnection at the dayside magnetopause. Although the theory and simulations have shown that the multiple active X‐lines and FRs can be produced simultaneously by the tearing instability in the magnetopause current sheet, there is no in‐situ evidence to directly support this scenario yet. Using high‐resolution measurements from the magnetospheric multiscale mission, we present a case study that all active X‐lines expected at the edges of three successive FRs were observed. These observations confirm that reconnection could simultaneously occur at multiple sites to produce the FRs at Earth's magnetopause. Interestingly, the electron‐scale Hall magnetic field was observed at the magnetosheath side in this multiple X‐line reconnection. This is due to the electron outflow jet deflected into the magnetosheath side by the strong core field of FR. Additionally, an ongoing secondary reconnection was observed at the center of one FR. Intense waves and current perturbations were observed in a smaller FR which was produced by this secondary reconnection.
Key Points
Ongoing multiple X‐line reconnection generates a series of flux ropes at the magnetopause
Electron‐scale Hall magnetic fields are formed due to the high deflection of electron jets caused by the core field of the flux rope
Secondary reconnection within the flux rope split the flux rope into smaller flux ropes and produces intense electromagnetic fluctuations
We report two lower thermospheric‐enhanced sodium layer (TeSL) cases observed at a low‐latitude station, Lijiang, China (26.7°N, 100.0°E), on 10 March and 10 April 2012, respectively. The TeSLs in ...the two cases were located at altitudes near 122 and 112 km, respectively. In addition, strong sporadic sodium layers (SSLs) near 100 km accompanied the TeSL observed on 10 March 2012. Both the TeSLs and SSLs exhibited tidal‐induced downward motion. The adjacent ground‐based and space‐borne ionospheric radio observations showed strong Es layers before the appearance of the TeSLs, suggesting an “ Es– TeSLs (SSLs)” chain formed through the tidal wind shear mechanism. Assuming that the vertical tidal wavelengths remain unchanged, it is found that in different regions caused by the tidal wind shear, different TeSLs evolution processes are expected: (1) in a tidal‐convergence region, a TeSL/SSL with a downward propagation phase is enhanced due to a rapid decrease in the Na+lifetime at the lower altitude; (2) in an ion convergence‐divergence interface region, a TeSL/SSL will still follow the tidal downward phase progression, but sodium density does not exhibit evident enhancement; and (3) when a TeSL/SSL enters into a tidal wind‐divergence zone, the layer density tends to decrease.
Key PointsTwo TeSLs events were observed at a low latitude regionRadio observations suggest TeSLs/SSLs might be formed through the same mechanismDifferent ion vertical motion region indicates different TeSL evolution process
Three-dimensionally macroporous (3DM) polymer membranes based on poly(vinylidene fluoride-co-hexafluropropylene) (P(VdF-HFP)) are simply prepared through etching calcium carbonate (CaCO3) hard ...template, which was filled in the polymer matrix previously. It is observed, from the SEM images, that some macropores within the obtained 3DM polymer membrane interconnect through many little holes, which would leave the continuous channels for ion transportation in the resultant polymer electrolyte. The 3DM polymer membrane made from the casting solution, in which the mass ratio of CaCO3 to P(VdF-HFP) is 2:1, has a porosity of 73.6%. The resultant 3DM polymer electrolyte (3DMPE) possesses high ionic conductivity of 1.38×10−3 S cm−1 at room temperature and low activation energy for ion transportation of 6.85kJmol−1. The assembled Li/LiMn2O4 cells exhibit good rate and cycling capabilities when using this 3DMPE membrane as a separator. The results suggest the 3DMPE could be promisingly applied in lithium-ion batteries.
Aim
This study assessed the effect of intra‐operative electrical nerve stimulation (INS) on pelvic autonomic nerve preservation (PANP) during laparoscopic resection for rectal cancer.
Method
A total ...of 189 consecutive cases of radical laparoscopic proctectomy were included. PANP was assessed visually or with INS. Urinary function was evaluated by residual urine volume (RUV), International Prostatic Symptom Score (IPSS) and recatheterization rate. Erectile function was evaluated using the International Index of Erectile Function (IIEF‐5) scale.
Results
INS successfully confirmed PANP in 65 (91.5%) patients, while direct vision confirmed PANP in only 72 (61.0%) patients. Compared with the successfully confirmed patients, failed patients in the INS group exhibited higher postoperative RUV (100.0 ± 34.6 vs 25.2 ± 13.6 ml, P = 0.003), higher IPSS (7 days, 20.0 ± 8.6 vs 6.5 ± 2.4, P = 0.012; 1 month, 13.5 ± 6.0 vs 5.3 ± 1.9, P = 0.020; 6 months, 11.7 ± 5.1 vs 4.5 ± 1.7, P = 0.018), a greater number of incidences of a micturition disorder (66.7% vs 1.5%, P = 0.000), higher recatheterization rates (33.3% vs 1.5%, P = 0.017) and a lower IIEF score at 3 months (8.25 ± 0.96 vs 10.93 ± 1.99, P = 0.012) and 6 months (12.50 ± 1.29 vs 15.63 ± 1.65, P = 0.001) postoperatively. Compared with the vision group, the INS group had less deterioration in postoperative RUV (31.5 ± 26.4 vs 54.0 ± 46.7 ml, P = 0.000), lower IPSS (7 days, 7.7 ± 5.0 vs 11.0 ± 6.6, P = 0.000; 1 month, 6.0 ± 3.3 vs 7.6 ± 5.4, P = 0.012) and higher IIEF score (3 months, 10.69 ± 2.07 vs 9.42 ± 2.05, P = 0.001; 6 months, 15.36 ± 1.85 vs 13.64 ± 2.00, P = 0.000) as well as a lower incidence of urination disorders (7.0% vs 17.8%, P = 0.038).
Conclusion
INS is effective for the accurate evaluation of PANP during radical laparoscopic proctectomy. Combined with INS, laparoscopic proctectomy is more effective in urogenital function protection.
In this study, experiments and simulations of Ne-like Ge soft X-ray lasers driven by nanosecond fundamental-frequency (1ω) and double-frequency (2ω) lasers are performed. The results show that 2ω ...lasers are also able to drive and produce Ne-like Ge soft X-ray lasers, even though the requirements for the driving conditions greatly increase compared to 1ω lasers. It is expected that the laser outputs at 23.2 and 23.6 nm will be stronger at higher power densities. The results provide a good foundation for executing experiments using Ne-like Ge soft X-ray lasers at existing large laser facilities, which cannot currently sustain 1ω drive lasers.
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